Power generator and electric washing machine therewith

The present invention relates to a power generator such as a motor or a linear motor used for home or industrial use, and an electric washing machine using the power generator.

Hereinafter, a conventional power generator will be described with reference to the drawings. FIG. 11 is a circuit diagram showing the configuration of a conventional power generator. In FIG. 11, a stator constituting the first object 1 and a rotor constituting the second object 2 rotatably provided inside the first object 1 are provided.

[0003] The first object 1 is a three-phase winding 3 composed of a winding 3a, a winding 3b, and a winding 3c wound in three phases on an iron core in which a silicon steel plate or the like is laminated, and a hole IC4a, a hole IC4b, and a hole. It is equipped with a position detecting means 4 configured by IC4c. Further, the second object 2 is provided with a two-pole permanent magnet 5. Reference numeral 6 denotes an inverter circuit that switches or cuts off the input / output of the current flowing through the 3-phase winding 3, and corresponds to the inverter circuit 6a corresponding to the winding 3a, the inverter circuit 6b corresponding to the winding 3b, and the winding 3c. It is equipped with an inverter circuit 6c. The inverter circuit 6a includes a series circuit of the first switching element 7a and the second switching element 8a, and also includes a driver 9a for opening and closing the first switching element 7a and the second switching element 8a. .. Further, the common connection point between the first switching element 7a and the second switching element 8a is connected to the winding 3a. The driver 9a includes a first drive circuit 10a that opens and closes and drives the first switching element 7a, and a second drive circuit 11a that opens and closes and drives the second switching element 8a. Further, 12a is a second DC power supply that supplies power to the second drive circuit 11a, and 13a is a third DC power supply that supplies power to the first drive circuit 10a.

Although not shown, the configurations of the inverter circuit 6b and the inverter circuit 6c are the same as those of the inverter circuit 6a, and the inverter circuit 6b includes the first switching element 7b and the second switching element 8b. It is equipped with a series circuit and a driver 9b consisting of a first drive circuit 10b and a second drive circuit 11b, and a second DC power supply 12b and a third DC power supply 13b are connected to the inverter circuit 6c. Is equipped with a series circuit of a first switching element 7c and a second switching element 8c, a driver 9c including a first drive circuit 10c and a second drive circuit 11c, and a second DC power supply 12c and a second. The DC power supply 13c of 3 is connected.

[0005] Further, reference numeral 14 denotes a first DC power source for supplying a current to the three-phase winding 3 via the inverter 6.

Reference numeral 15 denotes a three-phase distribution circuit that generates a timing for energizing the windings 3a to 3c, inputs a signal from the position detecting means 4, and outputs signals a to f by a logical formula. Here, the signal a is a signal for opening and closing the first switching element 7a of the inverter circuit 6a, and the signal b is a signal for opening and closing the second switching element 8a. The same applies to the signals c and d for the inverter circuit 6b and the signals e and f for the inverter circuit 6c. In addition, 16a, 16b, and 16c are AND circuits, respectively. The AND circuit 16a inputs the signal a, the signal b, and the PWM signal from the PWM circuit 17, outputs the logical product of the signal a and the PWM signal to the first drive circuit 10a, and outputs the signal b as it is to the second drive circuit 10a. Output to drive circuit 11a. The same applies to the AND circuit 16b and the AND circuit 16c. The PWM circuit 17 includes an oscillation circuit 18 that outputs a triangular wave voltage signal and a comparator 19.

[0007] The operation in the above configuration will be described. The position detecting means 4 detects the relative rotation angle of the second object 2 with respect to the first object 1, and the three-phase distribution circuit 15 corresponds to the rotation angle of the three first switching elements. Of the 7a to 7c and the three second switching elements 8a to 8c, the target to be turned on is determined, and the corresponding signals a to f are output to the AND circuits 16a to 16c as HIGH. If the signal a is HIGH, the AND circuit 16a outputs the logical product with the PWM signal to the first drive circuit 10a, and if the signal b is HIGH, outputs the logical product to the second drive circuit 11a as it is. The same applies to the AND circuit 16b and the AND circuit 16c. The first drive circuit 10a to which the logical product of the PWM signal is input and the second drive circuit 11a to which the HIGH signal b is input respectively output about 15 V to HIGH for the first switching element 7a and the first switching element 7a. Apply to the switching element 8a of 2 to turn it on. The same applies to the first drive circuits 10b to 10c and the second drive circuits 11b to 11c.

[0008] At this time, the third DC power supply 13a and the second DC power supply 12a supply electric power to the first drive circuit 10a and the second drive circuit 11a to operate them, respectively. The same applies to the third DC power supplies 13b to 13c and the second DC power supplies 12b to 12c.

[0009] By the above operation, the current corresponding to the rotation angle of the second object 2 detected by the position detecting means 4 is supplied to the windings 3a to 3c from the first DC power supply 14, and as a result, the second Torque is generated in the object 2 and it rotates, and power can be taken out.

[0010] Here, the PWM circuit 17 acts to equivalently adjust the voltage of the first DC power supply 14 to an arbitrary value of 100% or less, and operates the variable resistor 20 to output the bias power supply 21. By adjusting the voltage, the voltage at point g in the figure changes, and the PWM signal that switches between HIGH and LOW is output from the comparator 19 at the intersection of the voltage of the triangular wave output from the oscillation circuit 18 and the voltage at point g. Will be done. When the voltage at point g is increased, the ratio of the PWM signal output from the comparator 19 during the HIGH period increases, and conversely, when it is decreased, it decreases. Since the AND circuit 16a outputs the logical product of the PWM signal of the PWM circuit 17 and the signal a, the period during which the signal a turns on the first switching element 7a is adjusted by PWM control within a range of 100% or less. Control the value of the current flowing through line 3a. The same applies to the AND circuit 16b and the AND circuit 16c.

[0011] FIG. 12 is a circuit diagram showing in detail the configurations of the first drive circuit 10a and the second drive circuit 11a and their surroundings in the power generator shown in FIG. The same applies to the other first drive circuits 10b to 10c and the second drive circuits 11b to 11c.

[0012] In FIG. 12, the first DC power supply 14 is composed of a 100V 60Hz commercial power supply 22, a rectifying bridge 23, a choke coil 24, and a smoothing capacitor 25. Further, the first drive circuit 10a is composed of a photocoupler 26 composed of a light emitting diode and a phototransistor, an NPN transistor 27 and an NPN transistor 28, a PNP transistor 29, a resistor 30, and a resistor 31, via a resistor 32. It is connected to the output of AND circuit 16a. The second drive circuit 11a is composed of an NPN transistor 33, a PNP transistor 34, a resistor 35, and a resistor 36, and is directly connected to the output of the AND circuit 16a.

[0013] The switching power supply 37 is a power supply that realizes the second DC power supplies 12a to 12c and the third DC power supplies 13a to 13c, and includes an NPN diode 38, a drive circuit 39, a transformer 40, and a snubber 41. It is composed of a diode 42, a diode 43, a diode 44, a diode 45, a diode 46, an electrolytic capacitor 47, an electrolytic capacitor 48, an electrolytic capacitor 49, and an electrolytic capacitor 50, and a snubber 41 is composed of a resistor 51 and a capacitor 52. The output from the electrolytic capacitor 47 acts as a third DC power source 13a, and the output from the electrolytic capacitor 50 acts as a second DC power source 12a. Although the connections for the terminals j, k, l, and m are not shown, j and k are used as the third DC power supply 13b of the inverter circuit 6b, and l and m are the third DC power supply 13b of the inverter circuit 6c. Used as a DC power supply 13c. The output from the electrolytic capacitor 50 is also shared as the second DC power supplies 12b to 12c.

As described above, the DC power supplies for the second drive circuits 11a to 11c, that is, the second DC power supplies 12a to 12c can be shared, but the first drive circuits 10a to 10c For the third DC power supply 13a to 13c, a common DC power supply is used because the first switching element 7a to 7c, which is commonly used, is an N-channel IGBT (MOSFET) or NPN power transistor. This cannot be done, and as a result, three third DC power supplies 13a to 13c are required, and a commonly used 3-phase 6-stone inverter configuration requires at least 4 DC outputs.

[0015] [Problem to be Solved by the Invention] In such a conventional power generator, a first switching element 7a to 7c connected to the positive side of the first DC power supply 14 is opened and closed. The third DC power supplies 13a to 13c for the drive circuits 10a to 10c of the above are electrically isolated from the second drive circuits 11a to 11c and other circuit parts, respectively, and are generally of this type. The inverter uses a 3-phase 6-stone configuration, and a power supply that can output at least 4 direct currents independently by a switching power supply 37 etc. is used, so the power supply is large, heavy, and costly. It was.

[0016] The present invention solves the above-mentioned problems, simplifies the configuration of a DC power source for operating the first drive circuit and the second drive circuit in each inverter circuit, and is lightweight, inexpensive, and stably operating power. It is an object of the present invention to provide a generator and an electric washing machine using the generator.

[Means for Solving Problems]<u style="single">In order to achieve the above object, the power generator of the present invention</u>The duty is provided with a PWM circuit that PWM-controls the conduction period of the first switching element in each inverter circuit and a duty limiting circuit that limits the duty in the PWM control.<u style="single">The limiting circuit changes the upper limit that limits the duty according to the operating frequency of the inverter.</u>The terminal voltage of the bootstrap capacitor is maintained so that the first drive circuit can operate.<u style="single">It is a thing.</u>[0018] According to the present invention, the DC power supply for operating the first drive circuit can be stably operated while being composed only of the bootstrap capacitor, and a lightweight and low-cost power generator can be realized.<u style="single">Further, it is possible to realize a power generator that can obtain sufficient torque and output at high speed and can obtain sufficient torque and output within the range where the terminal voltage required for the bootstrap capacitor can be obtained even at low speed.</u>[Embodiment of the Invention] Claim 1<u style="single">In the invention described in the above, a first object having at least one winding, a second object provided so as to be relatively movable with respect to the first object, a first DC power supply, and both ends thereof. A series circuit connected to a first DC power supply and connecting a first switching element and a second switching element in series, a first drive circuit for opening and closing the first switching element, and the second switching element. A charging current is supplied from the second DC power supply when the second drive circuit for opening and closing, the second DC power supply for operating the second drive circuit, and the second switching element are conducting, and the second DC power supply is supplied. An inverter equipped with a bootstrap capacitor that serves as a DC power source for operating the drive circuit 1 for each winding, and a PWM circuit that PWM-controls the conduction period of the first switching element in each inverter circuit. And a duty limiting circuit that limits the duty in the PWM control, the duty limiting circuit changes the upper limit value that limits the duty according to the operating frequency of the inverter, and changes the terminal voltage of the bootstrap capacitor to the first. The drive circuit of 1 is maintained so that it can operate.</u>【0020】<u style="single">Bu</u>The art strap capacitor is a capacitor that acts as a DC power supply for the first drive circuit that opens and closes the first switching element, and can be realized by, for example, an electrolytic capacitor having a large electric capacity. Further, the second DC power supply that operates the second drive circuit that opens and closes the second switching element can be realized by, for example, a simple configuration for rectifying and smoothing a commercial power supply. Further, by connecting the bootstrap capacitor to the second DC power supply via a diode and a resistor, a charging current is supplied during a period in which the second switching element is conducting. The diode is provided to prevent backflow, and the resistor is provided to suppress an excessive charging current. Further, the duty limiting circuit is a means for limiting the duty in PWM control, and in the normal means, the voltage for increasing the duty corresponding to the operating frequency of the inverter is limited by a Zener diode or the like. The operating frequency of the inverter is detected by using the signal of the position detecting means by the Hall IC or the like, but it corresponds to the rotational speed in the rotational motion.

【0021】<u style="single"> As a result, the DC power supply that operates the first drive circuit can be stably operated while being composed of only the bootstrap capacitor, and a lightweight and low-cost power generator can be realized. Further, it is possible to realize a power generator that can obtain sufficient torque and output at high speed and can obtain sufficient torque and output within the range where the terminal voltage required for the bootstrap capacitor can be obtained even at low speed.</u>2. Claim 2<u style="single">In the invention according to claim 1, the second object includes a permanent magnet, and the first drive circuit and the second drive circuit are derived from the position detecting means for detecting the position of the permanent magnet. The first switching element and the second switching element are opened and closed, respectively, based on the signals of. The permanent magnet is fixed to the second object and is provided as described above.</u><u style="single">A mechanical force is generated by the field provided by the Kyu magnet and the current of the winding in the first object, and a highly efficient power generator can be realized.</u>3.<u style="single">The invention according to claim 1 or 2 is an electric washing machine provided with the power generator according to claim 1, and can realize a lightweight, low-cost, highly efficient, and highly reliable electric washing machine.</u>[Example] (Example 1) Hereinafter, Example 1 of the power generator of the present invention will be described with reference to the drawings.<u style="single">To do.</u>FIG. 1 is a circuit diagram showing the configuration of this embodiment, and FIG. 2 is a circuit diagram showing the configuration of the first drive circuit, the second drive circuit, and the periphery thereof in this embodiment. The same components as those in the conventional example shown in FIGS. 11 and 12 are assigned the same numbers, and detailed description thereof will be omitted.

[0025] The main difference between this embodiment and the conventional example is that the bootstrap capacitor for supplying power to the first drive circuits 10a to 10c instead of the third DC power supplies 13a to 13c in the conventional example. The power supply configuration is simplified by providing 53a to 53c, and the duty limiting circuit 54 is provided. By limiting the duty, the terminal voltage of the bootstrap capacitors 53a to 53c can be used to drive the first drive circuits 10a to 10c. I tried to keep it at a sufficient value.

[0026] In FIG. 1, the second DC power supply 12a supplies power to the second drive circuit 11a, the first drive circuit 10a is provided with a bootstrap capacitor 53a, and a resistor 55 and a diode 56 are provided. Is connected to the second DC power supply 12a in series. In FIG. 1, only the configuration of the inverter circuit 6a of one of the three phases is shown for the sake of simplicity, but the other two phases are also configured in exactly the same manner, and each of them has a second DC power supply. Suppose 12a is connected in common. The second DC power supply 12a may not be shared and may be provided individually for each inverter circuit, but in this embodiment, one second DC power supply 12a is sufficient. The bootstrap capacitor 53a is charged from the second DC power supply 12a via the resistor 55 and the diode 56 while the second switching element 8a is in a conductive state, and functions as a DC power supply for the first drive circuit 10a.

The output of the PWM circuit 17 is input to the AND circuit 16a, the AND circuit 16b, and the AND circuit 16c, and sends a PWM signal to the first drive circuits 10a to 10c, respectively, which is approximately equal to the oscillation frequency of the oscillation circuit 18. Although it outputs at 15 KHz, the duty limiting circuit 54 is composed of a resistor 57 and a Zener diode 58, and by limiting the voltage value input to the PWM circuit 17 to a predetermined value or less, the signal a, the signal c, and the signal The ratio of the period during which the first switching element 7a, the first switching element 7b, and the first switching element 7c are turned on, that is, the duty is limited to about 30% or less by e.

[0028] The speed detection circuit 59 detects the rotation speed of the second object 2 based on the signal from the position detecting means 4, and outputs an analog voltage corresponding to the detected rotation speed. Further, the difference between the DC voltage value input from the error amplifier 60 and the reference voltage source 61 and the output voltage of the speed detection circuit 59 is amplified and output to the PWM circuit 17 via the duty limiting circuit 54. As a result, in the power generator of this embodiment, the feedback operation is performed so that the input voltage difference of the error amplifier 60 is eliminated, and the rotation speed is controlled to be substantially constant.

[0029] FIG. 2 is a circuit diagram showing a configuration of a first drive circuit 10a, a second drive circuit 11a, and the periphery thereof in the present embodiment. The same components as in the conventional example are assigned the same numbers, and detailed description thereof will be omitted.

[0030] In FIG. 2, the configurations of the first DC power supply 14 and the second drive circuit 11a are the same as those of the conventional example. The configuration of the first drive circuit 10a is almost the same as that of the conventional example, but the signal from the AND circuit 16a is withstand voltage by the NPN transistor 62, the resistor 63, and the resistor 64 instead of the photocoupler 26 in the conventional example. Input is via a circuit. Further, the second DC power supply 12a is simply composed of a transformer 65, a rectifying bridge 66, a constant voltage IC 67, an electrolytic capacitor 68, and an electrolytic capacitor 69, and as described above, the output from the electrolytic capacitor 69 is the second. It is also shared by the drive circuit 11b and the second drive circuit 11c. In this embodiment, the first switching element 7a and the second switching element 8a are composed of a diode provided for reverse conduction and an IGBT. The same applies to the inverter circuit 6b and the inverter circuit 6c.

[0031] The operation in the above configuration will be described. The second drive circuits 11a to 11c operate by being supplied with a common power supply from the second DC power supply 12a. Further, the bootstrap capacitor 53a is charged from the second DC power supply 12a via the diode 56 and the resistor 55 while the second switching element 8a is on, and operates as the DC power supply of the first drive circuit 10a. .. In this case, the terminal voltage of the bootstrap capacitor 53a is discharged and lowered by operating the first switching element 7a, and the voltage drops especially when a power transistor having a large drive current is used as the first switching element 7a. Becomes larger. Therefore, in order to suppress the voltage drop, the ratio of the period during which the first switching element 7a is turned on, that is, the duty may be limited. In this embodiment, the duty limiting circuit 54 limits the ratio of the period during which the first switching element 7a is turned on to suppress the voltage drop of the bootstrap capacitor 53a, and boots even at startup or when the rotation speed is low. The terminal voltage of the strap capacitor 53a is secured above the voltage at which the first drive circuit 10a operates normally. The same applies to the bootstrap capacitors 53b to 53c.

[0032] As described above, the first switching elements 7a to 7c, which are commonly used, are configured to use N-channel IGBTs (MOSFETs), NPN power transistors that consume a large amount of current in the first drive circuits 10a to 10c, and the like. Even so, the power supply of the first drive circuit 10a to 10c can be composed entirely of the second DC power supply 12a and the bootstrap capacitors 53a to 53c, which simplifies the configuration of the device and reduces the cost. It can be realized.

[0033] As described above, according to the present embodiment, the first drive circuits 10a to 10c are provided with boot strap capacitors 53a to 53c as DC power supplies, and charging current is supplied from the second DC power supply 12a, respectively. In addition, by limiting the duty related to the conduction period of the first switching elements 7a to 7c to a predetermined value or less to secure the terminal voltage of the bootstrap capacitors 53a to 53c, the first drive circuits 10a to 10c The power supply for driving the power supply can be simplified and can be operated reliably.

[0034] In the present embodiment, the second object 2 is provided with the permanent magnet 5, but there is no particular limitation on the configuration thereof, for example, a configuration having a short-circuit winding or an exciting winding. It may be configured by connecting a first DC power supply, a configuration made of a ferromagnetic material having magnetic irregularities, or a configuration made of a magnetic material having a large magnetic hysteresis. In addition, the configuration of the winding and inverter circuit is not limited to three phases, and may be a single-phase four-stone system or a number of phases such as 2, 4, 5, 6, 7, .... Needless to say.

(Example 2) Hereinafter, Example 2 of the power generator of the present invention will be described with reference to the drawings.<u style="single">To do.</u>FIG. 3 is a circuit diagram showing the configuration of this embodiment. The same components as those in the first embodiment are assigned the same numbers, and detailed description thereof will be omitted. The difference between this embodiment and the first embodiment is that the duty limiting circuit 54 limits the duty only when the operating frequency of the inverter 6 is equal to or less than a predetermined value. This is intended to prevent torque and output from dropping due to duty restrictions at high speeds.

[0036] In FIG. 3, the duty limiting circuit 54 includes a voltage selector 70, a reference voltage source 71, a reference voltage source 72, and a frequency determination circuit 73. In this embodiment, the reference voltage source 71 uses a voltage source that outputs a voltage of 7 V, the reference voltage source 72 uses a voltage source that outputs a voltage of 14 V, and the frequency determination circuit 73 uses the Hall ICs 4a to 4c in the position detecting means 4. The frequency of the signal input from one of the above is detected, and if it is lower than 24Hz, it is connected to the α terminal side of the voltage selector 70, and if it is 24Hz or more, it is connected to the β terminal side of the voltage selector 70. I am trying to connect to. The oscillation circuit 18 outputs a triangular wave voltage of about 15 KHz, but since the peak value is 9.5 V in this embodiment, the PWM is under the condition that the input voltage of the PWM circuit 17 exceeds 9.5 V. The output of circuit 17 has a duty of 100%, that is, is uniformly HIGH.

[0037] The operation in the above configuration will be described. FIG. 4 is a characteristic diagram showing the operation of the duty limiting circuit 54 shown in FIG. In FIG. 4, the horizontal axis shows the frequency f of the signal from the Hall IC 4b, and the vertical axis shows the duty of the output signal of the PWM circuit 17, that is, the ratio of the period of HIGH. As shown in Fig. 4, under the condition of f &lt;24Hz, the duty is 80% by outputting the voltage of 7V from the duty limiting circuit 54, and under the condition of f 24Hz, the voltage of the duty limiting circuit 54 to 14V is output. The duty is 100%, that is, it is uniformly HIGH.

[0038] By the above operation, the duty is forcibly limited to 80% at low speed rotation, so that a sufficient charging current is sufficiently supplied to the bootstrap capacitors 53a to 53c, and the first switching element is used. 7a ~ 7c can be surely turned on. In this embodiment, since the second object 2 has two poles for the windings 3a to 3c, the bootstrap capacitor is limited to 80% by PWM at a rotation speed lower than 1440 rpm. 53a ~ 53c are charged. Further, the bootstrap capacitors 53a to 53c are charged at the fundamental frequency of the motor, that is, the signal frequency of the Hall IC 4b, without limiting the duty under the condition of 1440 rpm or more, and therefore ensuring sufficient torque and acceleration. As a result, a sufficient DC voltage is supplied to the first drive circuits 10a to 10c under any rotation speed condition. Moreover, since the duty is not limited in the high speed range, sufficient torque and output can be obtained.

[0039] As described above, according to the present embodiment, the terminal voltage of the bootstrap capacitors 53a to 53c is secured by limiting the duty only in the low speed range where the operating frequency of the inverter 6 is equal to or less than a predetermined value. However, in the high speed range, sufficient torque and output can be obtained without limiting the duty.

(Example 3) Hereinafter, Example 3 of the power generator of the present invention will be described with reference to the drawings.<u style="single">To do.</u>FIG. 5 is a circuit diagram showing the configuration of this embodiment. The same components as those in the first to first embodiments are assigned the same numbers, and detailed description thereof will be omitted. The difference between this embodiment and the second embodiment is that the duty limit in the low speed range is changed according to the operating frequency of the inverter. This is intended to obtain sufficient torque and output while limiting the duty even in the low speed range.

FIG. 6 is a characteristic diagram showing the operation of the duty limiting circuit 54 of FIG. In FIG. 6, the horizontal axis shows the frequency of the signal from the Hall IC 4b, and the vertical axis shows the duty of the output signal from the PWM circuit 17, that is, the ratio of the period of HIGH.

[0042] In this embodiment, the duty = 67% under the condition of f = 0, the duty = 100% under the condition of f = 40Hz, and the duty = 100% under the condition of f&gt; 40Hz. I try to make it 100%.

[0043] With the above configuration, in this embodiment, the terminal voltage of the bootstrap capacitors 53a to 53c is secured to a predetermined value or more under any frequency f condition, that is, a rotation speed condition, and the first drive circuit is used. By preventing the duty from being excessively limited while ensuring sufficient operation of 10a to 10c, the output and torque as a power generator can be fully exerted, and while ensuring reliability, it is high. A performance power generator can be realized.

[0044] In this embodiment, the duty relationship with respect to the frequency f is a straight line under the condition of 0 &lt;f &lt;40 Hz, but the present invention is not particularly limited to a straight line, and a curved line may be used. By optimizing the curve, it is possible to minimize the duty limit while ensuring the terminal voltage of the bootstrap capacitors 53a to 53c at any rotation speed, as a power generator. You can fully demonstrate your abilities.

[0045] As described above, according to the present embodiment, the duty limit in the low speed range is suppressed as much as possible corresponding to the operating frequency of the inverter 6, and the terminal voltage of the bootstrap capacitors 53a to 53c is secured while also in the low speed range. Sufficient torque and output can be obtained.

(Example 4) Hereinafter, Example 4 of the power generator of the present invention will be described with reference to the drawings.<u style="single">To do.</u>The difference between this embodiment and the third embodiment is that the duty limiting circuit 54 is provided with a boot voltage detection circuit 74, and feedback control is performed so that the terminal voltage of the boot strap capacitor 53a does not fall below a predetermined value. The other configurations are the same as in FIG.

FIG. 7 is a circuit diagram showing the configuration of the boot voltage detection circuit 74 in this embodiment. In FIG. 7, the boot voltage detection circuit 74 connects a series circuit of the Zener diode 75 and the light emitting diode side of the photocoupler 76 between both ends of the bootstrap capacitor 53a, and connects the output of the photocoupler 76 to the output of the photocoupler 76 via a resistor 77. Along with applying the voltage of the DC power supply 78, it is connected to the operational amplifier 80 via the resistor 79 to compare and amplify the voltage of the reference voltage source 81. Although the voltage of the DC power supply 78 is 15V in this embodiment, it can also be supplied from the output of the second DC power supply 12a shown in FIG.

[0048] Further, the output of the operational amplifier 80 is input to the PWM circuit 17, and the terminal voltage of the bootstrap capacitor 53a is the forward voltage drop of the Zener voltage of the Zener diode 75 and the light emitting diode constituting the photocoupler 76. When the added voltage of about 1.7V) is exceeded, the output voltage drops, and when it becomes lower than the voltage of the reference voltage source 81, the output voltage of the operational amplifier 80 rises, and the duty of the PWM signal of the PWM circuit 17 As a result, the feedback operation is performed so that the terminal voltage of the bootstrap capacitor 53a becomes almost constant.

When the rotation speed is high, the bootstrap capacitor 53a is frequently charged at the fundamental frequency, so that the output voltage of the operational amplifier 80 rises to about 15V and the duty becomes 100%. Here, in this embodiment, the boot voltage detection circuit 74 is provided only for the boot strap capacitor 53a of one of the three phases, but the other two phases are charged and discharged under the same conditions. A sufficient effect can be obtained without detecting it. However, it goes without saying that the operation can be compensated for the variation in the capacitance of the bootstrap capacitors 53a to 53c by providing them in other phases if necessary.

[0050] As described above, according to the present embodiment, the first drive circuits 10a to 10c are reliably operated by limiting the duty so that the terminal voltage of the bootstrap capacitors 53a to 53c does not fall below a predetermined value. Can be made to.

(Example 5) Hereinafter, Example 5 of the power generator of the present invention will be described with reference to the drawings.<u style="single">To do.</u>The difference between this embodiment and the fourth embodiment is that the duty limiting circuit 54 is provided with a boot voltage calculation circuit (not shown), and the terminal voltage of the boot strap capacitors 53a to 53c is operated by the first drive circuits 10a to 10c. The purpose is to limit the duty so that it is maintained at a predetermined value that is sufficient and minimum. Other configurations are the same as in Fig. 5.

[0052] The operation in the above configuration will be described. FIG. 8 is a characteristic diagram showing the rotation speed and the terminal voltage Vs (however, the bottom value of the ripple) of the bootstrap capacitor 53a under each duty condition in this embodiment. As shown in the figure, the value of the terminal voltage Vs with respect to the rotation speed of the power generator is greatly affected by the duty especially in the low speed region.

Based on the characteristics of FIG. 8, the boot voltage calculation circuit calculates the duty required to maintain the terminal voltage Vs of the boot strap capacitor 53a at a predetermined value with respect to the current rotation speed, and the PWM circuit 17 Output to and give feedback. As a result, the terminal voltage Vs of the bootstrap capacitor 53a can be controlled to be maintained at a predetermined value.

[0054] In this embodiment, the estimated value of the terminal voltage Vs is 8V under the condition that the duty is 90% and 500 rpm, and the estimated value of the terminal voltage Vs is 8V even under the condition that the duty is 100% and 800 rpm. It becomes. Further, in this embodiment, since the voltage at which the first drive circuits 10a to 10c operate reliably is 8V, the terminal voltage Vs is maintained at 8V and operated by performing the above feedback operation.

The boot voltage calculation circuit may have the characteristics shown in FIG. 8 by a mathematical formula, or may be stored in a memory as a data table.

[0056] As described above, according to the present embodiment, the duty is optimally limited by limiting the duty so as to maintain the terminal voltage of the bootstrap capacitors 53a to 53c at the minimum necessary predetermined value. Therefore, the maximum torque and output can be obtained.

(Example 6) Hereinafter, Example 6 of the power generator of the present invention will be described with reference to the drawings.<u style="single">To do.</u>FIG. 9 is a circuit diagram showing the configuration of this embodiment. The same components as those in Examples 1 to 5 are assigned the same numbers, and detailed description thereof will be omitted.

[0058] The configuration of this embodiment is provided by connecting a charging resistor 82 of 75 kΩ to both ends of the second switching element 8a, and the other configurations are the same as those of any of the first to fifth embodiments. ..

[0059] The difference between this embodiment and the first to fifth embodiments is that the charging resistor 82 is provided, and the bootstrap capacitors 53a to 53c are charged even before the second switching elements 8a to 8c are opened and closed. I have done so. This is related to guaranteeing the operation of the inverter 6 at the time of starting.

[0060] In FIG. 9, when the operation is stopped,<u style="single">That is,</u>When all the signals a to f are LOW, all of the second switching elements 8a to 8c (three exist because they are three phases in this embodiment) are in the off state. .. At this time, in order to charge the bootstrap capacitor 53a from the second DC power supply 12a, it is necessary to draw the charging current of the bootstrap capacitor 53a from the emitter terminal of the first switching element 7a. By providing the charging resistor 82, the path of the charging current is secured and the bootstrap capacitor 53a is charged, so that the first drive circuit 10a operates reliably when the device is started, and the first drive circuit 10a is operated. The turn-on of the switching element 7a of 1 is surely executed.

[0061] Since the configuration of this embodiment is three-phase, the other two phases are also provided with boot strap capacitors 53b to 53c. Regarding these, the winding 3a, the winding 3b, and the winding By being supplied through 3c, only one charging resistor 82 can charge all three-phase bootstrap capacitors 53a-53c. Two or more charging resistors may be connected, in which case the charging current will be large, sufficient charging will be performed even if the charging time is short, and the charging currents of multiple bootstrap capacitors will be equalized. You can expect the effect such as being able to plan.

[0062] Further, in this embodiment, the voltage of the first DC power supply 14 is 140 V, the capacitance of the bootstrap capacitors 53a to 53c is 47 μf, and the resistance value of the charging resistor 82 is 75 kΩ. Is about 0.2mA, and the time to charge the three-phase bootstrap capacitors 53a to 53c (three in total) to about 8V is about 7 seconds, so the power generator of this example is used for the electric washing machine. If this is the case, the waiting time from power-on to startup can be short enough.

[0063] Further, when the power generator is driven from the load side while stopped, the permanent magnet 5 provided in the second object 2 generates an induced power proportional to the speed in the windings 3a to 3c. In this embodiment, since the resistance value of the charging resistor 82 is as large as 75 kΩ, the current due to the induced power is as small as 1.8 mA or less, and therefore the windings 3a to 3c are not burnt. The configuration of the second object 2 is not limited to the one using the permanent magnet 5, and other configurations may be used. In this case as well, the boot strap is provided with a simple configuration of providing a charging resistor 82. Capacitors 53a to 53c can be charged, and a low-cost power generator can be realized.

[0064] As described above, according to the present embodiment, the bootstrap capacitors 53a to 53c are charged even before the second switching elements 8a to 8c start the opening / closing operation, so that the power is surely powered. The generator can be activated.

(Example 7) Hereinafter, an embodiment of an electric washing machine using the power generator of the present invention will be described with reference to the drawings.<u style="single">To do.</u>[0066] FIG. 9 is a cross-sectional view showing the configuration of this embodiment. In FIG. 9, the washing machine outer frame 83 suspends the water receiving tank 85 by four hanging rods 84, and the washing / dehydrating tank 86 is rotatably arranged in the water receiving tank 85 for washing / removing. A stirring blade 87 is rotatably arranged at the bottom of the water tank 86. The power generator 88 including the first object 1 and the second object 2 and the inverter 6 described in the first to sixth embodiments includes the stirring blade 87 and the washing via the V-belt 89 and the reduction mechanism 90. It also drives the dehydration tank 86. 91 is a drain valve and 92 is a water supply valve. The control device 93 controls each process of washing, rinsing, and dehydration by, for example, information input from the input means, and controls the power generator 88.

[0067] The operation in the above configuration will be described. When the power generator 88 is driven by a command from the control device 93 with clothes in the washing / dehydrating tank 86, the power generator 88 rotates the stirring blade 87 via the V-belt 89 and the reduction mechanism 90. Perform washing by letting. In addition, the washing / dehydrating tub 86 rotates during dehydration. Switching between washing and dehydration is performed in conjunction with the drain valve 91 by a command from the control device 93, and also in conjunction with the deceleration on / off of the planetary gear provided inside the reduction mechanism 90.

[0068] [Effect of the invention]<u style="single">As described above, the invention according to claim 1 of the present invention</u>A first object having at least one winding, a second object provided so as to be relatively movable relative to the first object, a first DC power supply, and both ends of the first DC power supply. A series circuit that is connected and connects the first switching element and the second switching element in series, a first drive circuit that opens and closes the first switching element, and a second drive that opens and closes the second switching element. When the drive circuit, the second DC power supply that operates the second drive circuit, and the second switching element are conducting, a charging current is supplied from the second DC power supply to operate the first drive circuit. In the PWM control, an inverter having an inverter circuit provided with a bootstrap capacitor as a DC power supply for each winding, a PWM circuit for PWM control of the conduction period of the first switching element in each of the inverter circuits, and a PWM control. A duty limiting circuit for limiting the duty is provided, and the duty is said to be limited.<u style="single">The limiting circuit changes the upper limit that limits the duty according to the operating frequency of the inverter.</u>The terminal voltage of the bootstrap capacitor is maintained so that the first drive circuit can operate.<u style="single">From</u>The DC power supply that operates the first drive circuit can be operated stably while being composed only of the bootstrap capacitor, and a lightweight and low-cost power generator can be realized.<u style="single">Further, it is possible to realize a power generator that can obtain sufficient torque and output at high speed and can obtain sufficient torque and output within the range where the terminal voltage required for the bootstrap capacitor can be obtained even at low speed.</u>[0069] In claim 2.<u style="single">In the described invention, the second object includes a permanent magnet, and the first drive circuit and the second drive circuit each have a first drive circuit based on a signal from a position detecting means for detecting the position of the permanent magnet. Since the switching element and the second switching element are driven to open and close, a highly efficient power generator can be realized.</u>[0070] Claim 3<u style="single">Since the described invention includes the power generator according to claim 1 or 2, it is possible to realize a lightweight, low-cost, highly efficient, and highly reliable electric washing machine.</u>BRIEF DESCRIPTION OF THE DRAWINGS [Fig. 1] A circuit diagram showing a configuration of a first embodiment of the power generator of the present invention [FIG. 2] A first drive circuit, a second drive circuit, and their surroundings in the same embodiment. Circuit diagram showing the configuration [Fig. 3] Circuit diagram showing the configuration of the second embodiment of the power generator of the present invention [Fig. 4] Characteristic diagram showing the operation of the same embodiment [Fig. 5] Implementation of the power generator of the present invention Circuit diagram showing the configuration of Example 3 [Fig. 6] Characteristic diagram showing the operation of the same embodiment [Fig. 7] Circuit diagram showing the configuration of the boot voltage detection circuit in Example 4 of the power generator of the present invention [Fig. 8] A characteristic diagram showing the relationship between the duty used by the boot voltage calculation circuit in Example 5 of the power generator of the present invention and the terminal voltage of the bootstrap capacitor and the rotation speed [FIG. 9] Example of the power generator of the present invention. Circuit diagram showing the configuration of 6 [Fig. 10] Cross-sectional view showing the configuration of an embodiment of the electric washing machine of the present invention [Fig. 11] Circuit diagram showing the configuration of a conventional power generator [Fig. 12] In the conventional example Circuit diagram showing the configuration of the first drive circuit, the second drive circuit, and its surroundings [Explanation of symbols] 1 First object 2 Second object 3 Three-phase winding 3a, 3b, 3c winding 4 Position detection means 4a, 4b, 4c Hall IC 5 Permanent magnet 6 Inverter 6a, 6b, 6c Inverter circuit 7a, 7b, 7c First switching element 8a, 8b, 8c Second switching element 9a, 9b, 9c Driver 10a, 10b, 10c 1st drive circuit 11a, 11b, 11c 2nd drive circuit 12a, 12b, 12c 2nd DC power supply 13a, 13b, 13c 3rd DC power supply 14 1st DC power supply 15 3-phase distribution circuit 16a, 16b, 16c AND circuit 17 PWM circuit 18 Oscillation circuit 19 Comparator 20 Variable resistance 21 Bias power supply 22 Commercial power supply 23 Rectification bridge 24 Chalk coil 25 Smoothing capacitor 26 Photocoupler 27, 28, 33, 38 NPN transistor 29, 34 PNP transistor 30, 31, 32, 35, 36, 51 Resistance 37 Switching power supply 39 Drive circuit 40 Transformer 41 Snubber 42, 43, 44, 45, 46 Diode 47, 48, 49, 50 Electrolytic Capacitor 52 Capacitor 53a, 53b, 53c Bootstrap Capacitor 54 Duty Limit Circuit 55, 57 Resistance 56 Diode 58 Zener Diode 59 Speed Detection Circuit 60 Error Amplifier 61 Reference Voltage Source 62 NPN Transistor 63, 64 Resistance 65 Transformer 66 Rectifier bridge 67 Constant voltage IC 68, 69 Electrolytic capacitor 70 Voltage selector 71, 72 Reference voltage source 73 Frequency determination circuit 74 Boot voltage detection circuit 75 Zener diode 76 Photocoupler 77, 79 Resistance 78 DC power supply 80 Computational amplifier 81 Reference Voltage source 82 Charging resistance 83 Washing machine outer frame 84 Hanging rod 85 Water receiving tank 86 Washing and dehydrating tank 87 Stirring blade 88 Power generator 89 V belt 90 Deceleration mechanism 91 Drain valve 92 Water supply valve 93 Control device