Controller of electric vehicle

The present invention relates to a control device for an electric vehicle equipped with a system in which a DC power supply voltage is converted by a voltage conversion means to generate a system voltage, and the system voltage is used to drive an AC motor via an inverter.

In an electric vehicle equipped with an AC motor as a vehicle power source, as described in Patent Document 1 (Japanese Patent Laid-Open No. 2003-244801) and Patent Document 2 (Japanese Patent Laid-Open No. 2004-274945), the vehicle It is equipped with an AC motor for driving the drive wheels and an AC motor for generating power by being driven by an internal combustion engine, and generates a DC voltage that is boosted by a boost converter from the DC power supply (secondary battery) in the power supply line. , Each AC motor is connected to this power supply line via an inverter, and the DC voltage boosted by the boost converter is converted to AC voltage by the inverter to drive the AC motor, or the AC voltage generated by the AC motor is converted to the inverter. There is a case in which the DC voltage is converted into a DC voltage, and the DC voltage is stepped down by a boost converter so that the battery can recover the DC voltage.

In such a system, as described in Patent Document 3 (Japanese Unexamined Patent Publication No. 2005-51898), in order to stabilize the system voltage generated in the power supply line, the system voltage is detected by a voltage sensor. Some boost converters are feedback-controlled so that the deviation between the target value of the system voltage and the detected value becomes small.<patcit num="1"><text>Japanese Unexamined Patent Publication No. 2003-244801</text></patcit><patcit num="2"><text>Japanese Unexamined Patent Publication No. 2004-274945</text></patcit><patcit num="3"><text>Japanese Unexamined Patent Publication No. 2005-51898</text></patcit>

<p> By the way, when the driving power or the generated power of the AC motor suddenly changes due to a change in the operating state of the vehicle or the like, the system voltage may suddenly fluctuate accordingly. However, in a system such as the technique of Patent Document 3 in which the boost converter is feedback-controlled so as to reduce the deviation between the target value and the detected value of the system voltage, the change in the system voltage is actually detected and then the system voltage is changed. Since the boost converter is controlled so as to suppress the change in the system voltage, the control that suppresses the change in the system voltage is delayed in response to the actual change in the system voltage, and the system voltage is effectively used. It may not be possible to stabilize it. Therefore, the system voltage may become excessive temporarily, the control of the AC motor may become unstable, or the overvoltage may be applied to the electronic device connected to the power supply line.</p><p> As a countermeasure, there is a method of increasing the system voltage stabilization effect by increasing the capacity of the smoothing capacitor that smoothes the system voltage, but this method leads to an increase in the size and cost of the smoothing capacitor, which has become important in recent years. There is a problem that the demand for miniaturization and cost reduction of the system, which is a technical problem, cannot be satisfied.</p><p> The present invention has been made in consideration of these circumstances, and therefore, an object of the present invention is to enhance the effect of stabilizing the system voltage and to satisfy the demands for miniaturization and cost reduction of the system. The purpose is to provide a control device for an electric vehicle.</p>

<p> In order to achieve the above object, the invention according to claim 1 is driven by a voltage conversion means for converting a voltage of a DC power supply to generate a system voltage in a power supply line, an inverter connected to the power supply line, and the inverter. In a control device of an electric vehicle including at least one motor drive unit composed of an AC motor, a system voltage change prediction means for predicting a change in system voltage based on a power change of the motor drive unit and a system voltage change prediction means. Configuration with system voltage control means that executes predicted voltage stabilization control that controls the voltage conversion means based on the change in system voltage predicted in (hereinafter referred to as "predicted system voltage change") to stabilize the system voltage. It is the one.</p><p> When the electric power of the motor drive unit changes due to a change in the operating state of the vehicle or the like, the system voltage changes accordingly. Therefore, if the electric power change of the motor drive unit is used, the change in the system voltage can be predicted with high accuracy. Then, by executing the predicted voltage stabilization control that stabilizes the system voltage by controlling the voltage conversion means based on the predicted system voltage change (the predicted system voltage change), the system voltage actually changes. It is possible to effectively suppress the change in the system voltage by executing the predicted voltage stabilization control before or with almost no delay with respect to the change in the actual system voltage, and the effect of stabilizing the system voltage can be achieved. Can be enhanced. Moreover, it is not necessary to increase the capacity of the smoothing capacitor, which can meet the demands of system miniaturization and cost reduction, which are important technical issues in recent years, and improve the system voltage stabilization effect and miniaturize the system. It is possible to achieve both cost reduction and cost reduction.</p><p> In this case, as a specific method for predicting the change in the system voltage, for example, as in claim 2, the power change of the motor drive unit is calculated based on the command value of the control amount of the motor drive unit, and the motor The predicted system voltage change may be calculated based on the power change of the drive unit. Since the power of the motor drive unit changes according to the command value of the control amount of the motor drive unit (for example, the torque command value of the AC motor), if the command value of the control amount of the motor drive unit is used, the power of the motor drive unit The change can be calculated accurately.</p><p> Alternatively, as in claim 3, the power change of the motor drive unit is calculated based on the detected value of the control state of the motor drive unit, and the predicted system voltage change is calculated based on the power change of the motor drive unit. You can do it. The detected value of the control state of the motor drive unit (for example, the current detection value of the AC motor) is data that accurately reflects the actual power of the motor drive unit. , The power change of the motor drive unit can be calculated accurately.</p><p> Further, as a specific method of predictive voltage stabilization control, for example, as in claim 4, the voltage is based on the output characteristics of the voltage conversion means (for example, the relationship between the input voltage, the output voltage, and the energization duty ratio). In the case of a system that calculates the feedforward control amount of the voltage conversion means so that the output voltage of the conversion means becomes the target value of the system voltage, the feedforward control amount is predicted by correcting it using the prediction system voltage change. The voltage stabilization control may be executed. In this way, it is possible to accurately execute the predicted voltage stabilization control by reflecting the change in the voltage of the prediction system in the feedforward control amount of the voltage conversion means.</p><p> Further, in the case of a system for calculating the feedback control amount of the voltage conversion means so as to reduce the deviation between the target value and the detected value of the system voltage as in claim 5, the feedback control amount is predicted as the system voltage change. The predicted voltage stabilization control may be executed by correcting with. In this way, it is possible to accurately execute the predicted voltage stabilization control by reflecting the change in the voltage of the prediction system in the feedback control amount of the voltage conversion means.</p><p> Further, as in claim 6, the predicted voltage stabilization control may be prohibited when the power change of the motor drive unit or the predicted system voltage change is equal to or less than a predetermined value. In this way, when the power change of the motor drive unit or the predicted system voltage change is equal to or less than a predetermined value, the system voltage is predicted to be in a substantially steady state (or the change in the system voltage is within the allowable range). In such a case, if the predicted voltage stabilization control is executed, it is judged that the system voltage may be disturbed, and the predicted voltage stabilization control can be prohibited. Disturbance can be prevented in advance.</p><p> Further, as in claim 7, the predicted voltage stabilization control may be executed only when the power change of the motor drive unit or the predicted system voltage change occurs in the upward direction of the system voltage. In this way, if the power change of the motor drive unit or the predicted system voltage change occurs in the upward direction of the system voltage, the system voltage may become excessive and the overvoltage may be applied to the electronic device. Judging and executing the predicted voltage stabilization control, but if the power change of the motor drive unit or the predicted system voltage change occurs in the downward direction of the system voltage, it is judged that the system voltage is not likely to become excessive. Therefore, the predicted voltage stabilization control can be prevented from being executed. As a result, it is possible to prevent the system voltage from becoming excessive and applying the overvoltage to the electronic device, and to avoid executing the predicted voltage stabilization control more than necessary.</p>

Hereinafter, some examples embodying the best mode for carrying out the present invention will be described.

Example 1 of the present invention will be described with reference to FIGS. 1 to 5. First, a schematic configuration of a hybrid vehicle motor control system will be described with reference to FIG. The engine 10 which is an internal combustion engine and the first and second AC motors 11 and 12 are mounted, and the first AC motor 11 is mainly used as a generator to generate power driven by the engine 10, and the second AC. The motor 12 is mainly used as a power source for driving the drive wheels of the vehicle.

A boost converter 14 (voltage conversion means) is connected to the DC power supply 13 composed of a secondary battery or the like, and the boost converter 14 boosts the DC voltage of the DC power supply 13 between the power supply line 15 and the ground line 16. It has the function of generating a DC system voltage or lowering the system voltage and returning the power to the DC power supply 13. A smoothing capacitor 17 for smoothing the system voltage and a voltage sensor 20 for detecting the system voltage are connected between the power supply line 15 and the ground line 16.

Further, voltage-controlled three-phase first and second inverters 18 and 19 are connected between the power supply line 15 and the ground line 16, and the first AC motor 11 is driven by the first inverter 18. At the same time, the second AC motor 12 is driven by the second inverter 19. The first inverter 18 and the first AC motor 11 constitute the first motor drive unit 21, and the second inverter 19 and the second AC motor 12 constitute the second motor drive unit 22. The first and second AC motors 11 and 12 are three-phase permanent magnet type synchronous motors, respectively, which are equipped with permanent magnets and are equipped with rotor rotation position sensors 23 and 24 that detect the rotation position of the rotor, respectively. Has been done. The rotation speeds of the AC motors 11 and 12 are calculated based on the output signals of the rotor rotation position sensors 23 and 24.

The boost converter 14 is provided with a reactor 25 and two switching elements 26, and a freewheeling diode 27 is connected in parallel to each switching element 26. In addition, the voltage-controlled three-phase first and second inverters 18 and 19 have six switching elements 28 and 29 (switching elements for each phase of the upper arm and switching elements for each phase of the lower arm), respectively. The freewheeling diodes 30 and 31 are connected in parallel to the switching elements 28 and 29, respectively.

The first inverter 18 converts the DC voltage of the power supply line 15 (the system voltage boosted by the boost converter 14) into a three-phase AC voltage based on the three-phase voltage command signal output from the motor control circuit 32. Then, the first AC motor 11 is driven. The U-phase current and W-phase current of the first AC motor 11 are detected by the current sensors 33 and 34, respectively. On the other hand, the second inverter 19 converts the DC voltage of the power supply line 15 into a three-phase AC voltage based on the three-phase voltage command signal output from the motor control circuit 32 to convert the second AC motor 12 into a three-phase AC voltage. Drive. The U-phase current and W-phase current of the second AC motor 12 are detected by the current sensors 35 and 36, respectively.

Further, in the first embodiment, the system voltage is controlled as follows by executing each routine for system voltage control of FIGS. 2 and 3 described later by the motor control circuit 32. The feed forward control amount of the boost converter 14 so that the output voltage of the boost converter 14 becomes the target value of the system voltage based on the output characteristics of the boost converter 14 (for example, the relationship between the input voltage, the output voltage, and the energization duty ratio). ff (hereinafter referred to as "F / F control amount Duty.ff") is calculated, and the feedback control amount Duty.fb (hereinafter referred to as "F / F control amount Duty.ff") of the boost converter 14 is used so as to reduce the deviation between the detected value of the system voltage and the target value. (Indicated as "F / B control amount Duty.fb") is calculated, and the energization duty ratio Duty of the boost converter 14 is calculated using these F / F control amount Duty.ff and the F / B control amount Duty.fb. calculate. The switching element 26 of the boost converter 14 is controlled by this energization duty ratio Duty, and the system voltage is controlled to the target value.

When controlling the system voltage in this way, in the first embodiment, the power change amount ΔPmg1 of the first motor drive unit 21 per predetermined time and the power change amount of the second motor drive unit 21 per predetermined time. The total value of ΔPmg2 is obtained as the motor power change amount ΔP, and the system voltage change amount ΔV per predetermined time is predicted based on the motor power change amount ΔP. Here, each power change amount ΔPmg1, ΔPmg2, ΔP has a positive value in the direction of supplying power to the smoothing capacitor 17, for example.

When the power change amount ΔPmg1 of the first motor drive unit 21 or the power change amount ΔPmg2 of the second motor drive unit 21 changes due to a change in the operating state of the vehicle or the like, and the motor power change amount ΔP changes, the system responds accordingly. Since the voltage changes, the amount of change ΔV of the system voltage can be predicted with high accuracy by using the amount of change ΔP of the motor power.

Then, by executing the predicted voltage stabilization control that stabilizes the system voltage by controlling the boost converter 14 based on the predicted system voltage change amount ΔV (hereinafter referred to as predicted system voltage change amount ΔV), it is actually performed. It is possible to effectively suppress the change in the system voltage by executing the predicted voltage stabilization control before the change in the system voltage occurs or with almost no delay with respect to the actual change in the system voltage. Become.

Specifically, when calculating the F / F control amount Duty.ff of the boost converter 14, the F / F control amount Duty.ff of the boost converter 14 is corrected by using the prediction system voltage change amount ΔV. Prediction system The voltage change amount ΔV is reflected in the F / F control amount Duty.ff of the boost converter 14 to execute the prediction voltage stabilization control. Hereinafter, the processing contents of each routine for system voltage control of FIGS. 2 and 3 executed by the motor control circuit 32 will be described.

[System voltage control routine] The system voltage control routine shown in FIG. 2 is repeatedly executed at a predetermined cycle while the power of the motor control circuit 32 is turned on, and serves as a system voltage control means within the scope of claims. When this routine is activated, first, in step 101, the system voltage change prediction routine of FIG. 3 described later is executed to calculate the prediction system voltage change amount ΔV based on the motor power change amount ΔP.

After that, the process proceeds to step 102, and it is determined whether or not the absolute value of the predicted system voltage change amount ΔV is equal to or less than a predetermined value. As a result, when it is determined that the absolute value of the predicted system voltage change amount ΔV is equal to or less than a predetermined value, the system voltage is predicted to be in a substantially steady state (or the change in the system voltage is within the allowable range). In such a case, if the predicted voltage stabilization control is executed, it is judged that the system voltage may be disturbed, and the process proceeds to step 103, and the predicted system voltage change amount ΔV is forcibly set to 0. By prohibiting the predicted voltage stabilization control, the minute correction of the system voltage by the predicted voltage stabilization control is prevented.

On the other hand, if it is determined in step 102 that the absolute value of the predicted system voltage change amount ΔV is larger than the predetermined value, the process of step 103 is skipped and the process proceeds to step 104, and the output characteristics of the boost converter 14 ( For example, the input voltage Vb of the boost converter 14 and the target value Vsys of the system voltage so that the output voltage of the boost converter 14 becomes the target value Vsys.tar of the system voltage based on the relationship between the input voltage, the output voltage, and the energization duty ratio. Calculate the F / F control amount Duty.ff (= Vb /Vsys.tar) of the boost converter 14 using .tar. At this time, the F / F control amount Duty.ff of the boost converter 14 is corrected by correcting the target value Vsys.tar of the system voltage using the predicted system voltage change amount ΔV by the following equation. Duty.ff = Vb / (Vsys.tar -ΔV)

As a result, the predicted system voltage change amount ΔV is reflected in the F / F control amount Duty.ff of the boost converter 14 to execute the predicted voltage stabilization control. However, when the predicted system voltage change amount ΔV = 0, the predicted voltage stabilization control is not executed.

After this, proceed to step 105 to find the deviation (Vsys.cur -Vsys.tar) between the system voltage detection value Vsys.cur and the target value Vsys.tar. boost converter 14 is by PI control or PID control so as reduce . Calculate the F / B control amount Duty.fb by a map or a mathematical formula. Duty.fb = f (Vsys.cur -Vsys.tar)

After that, the process proceeds to step 106, and the energization duty ratio Duty, which is the final control amount of the boost converter 14, is calculated by the following equation using the F / F control amount Duty.ff and the F / B control amount Duty.fb. .. Duty = Duty.ff + Duty.fb The switching element 26 of the boost converter 14 is controlled by this energization duty ratio Duty, and the system voltage is controlled to the target value.

[System voltage change prediction] The system voltage change prediction routine shown in FIG. 3 is a subroutine executed in step 101 of the system voltage control routine of FIG. 2, and serves as a system voltage change prediction means within the scope of claims.

When this routine is started, first, in step 201, the electric power Pmg1 of the first motor drive unit 21 is calculated based on the torque command value Tmg1 of the first AC motor 11 and the rotation speed Nmg1, and this time it is calculated. By calculating the difference ΔPmg1 between the electric power Pmg1 (i) and the previously calculated electric power Pmg1 (i-1), the amount of change in the electric power of the first motor drive unit 21 per predetermined time Δt (per calculation cycle Δt of this routine). Find ΔPmg1. ΔPmg1 = Pmg1 (i) -Pmg1 (i-1)

The power change amount ΔPmg1 of the first motor drive unit 21 has, for example, a positive value in the direction of supplying power to the smoothing capacitor 17. Since the power Pmg1 of the first motor drive unit 21 changes according to the torque command value Tmg1 and the rotation speed Nmg1 of the first AC motor 11, if the torque command value Tmg1 and the rotation speed Nmg1 are used, the first The power change amount ΔPmg1 of the motor drive unit 21 can be calculated accurately.

After that, the process proceeds to step 202, and the electric power Pmg2 of the second motor drive unit 22 is calculated based on the torque command value Tmg2 of the second AC motor 12 and the rotation speed Nmg2. By calculating the difference ΔPmg2 from the previously calculated power Pmg2 (i-1), the power change amount ΔPmg2 of the second motor drive unit 22 per predetermined time Δt (per the calculation cycle Δt of this routine) is obtained. ΔPmg2 = Pmg2 (i) -Pmg2 (i-1) The power change amount ΔPmg2 of the second motor drive unit 22 has, for example, a positive value in the direction of supplying power to the smoothing capacitor 17.

Since the power Pmg2 of the second motor drive unit 22 changes according to the torque command value Tmg2 and the rotation speed Nmg2 of the second AC motor 12, if the torque command value Tmg2 and the rotation speed Nmg2 are used, the second The power change amount ΔPmg2 of the motor drive unit 22 can be calculated accurately.

After that, the process proceeds to step 203, and the total value of the power change amount ΔPmg1 of the first motor drive unit 21 and the power change amount ΔPmg2 of the second motor drive unit 21 is obtained as the motor power change amount ΔP. ΔP = ΔPmg1 + ΔPmg2

After that, the process proceeds to step 204, and the predicted system voltage change amount ΔV is calculated from the following equation (1) based on the motor power change amount ΔP.

<maths num="1"><img file="JP4968630B2_D0001.tif" /></maths>

When the calculation cycle Δt and the capacitance C of the smoothing capacitor 17 are constant as in the first embodiment, as shown in FIG. 4, the system voltage corresponds to the motor power change amount ΔP and the system voltage. Since the amount of change changes, as shown in Fig. 5, the amount of change in motor power is referred to the map of the predicted system voltage change amount ΔV with the motor power change amount ΔP and the system voltage detection value Vsys.cur as parameters. The predicted system voltage change amount ΔV may be calculated according to ΔP and the detected value Vsys.cur of the system voltage.

Also, when calculating the predicted system voltage change amount ΔV using the above equation (1) or the map shown in Fig. 5, the target value Vsys.tar of the system voltage should be used instead of the detected value Vsys.cur of the system voltage. You may.

In the first embodiment described above, the system voltage change amount ΔV is predicted based on the motor power change amount ΔP, and the F / F control amount Duty.ff of the boost converter 14 is calculated using the predicted system voltage change amount ΔV. By correcting, the predicted voltage stabilization control that stabilizes the system voltage is executed, so there is almost no delay before the actual change in the system voltage occurs or with respect to the actual change in the system voltage. In addition, the predicted voltage stabilization control can be executed to effectively suppress the change in the system voltage, and the system voltage stabilization effect can be enhanced. Moreover, it is not necessary to increase the capacity of the smoothing capacitor 17, and it is possible to meet the demands of system miniaturization and cost reduction, which are important technical issues in recent years, and improve the system voltage stabilization effect and the system. It is possible to achieve both miniaturization and cost reduction.

Further, in the first embodiment, when the absolute value of the predicted system voltage change amount ΔV is equal to or less than a predetermined value, the system voltage is predicted to be in a substantially steady state (or the change in the system voltage is within the allowable range). In such a case, if the predicted voltage stabilization control is executed, it is judged that the system voltage may be disturbed, and the predicted voltage stabilization control is prohibited. Therefore, the system voltage is almost in a steady state ( Alternatively, when the change in the system voltage is predicted to be within the permissible range), it is possible to prevent the system voltage from being disturbed by the predicted voltage stabilization control.

When the absolute value of the motor power change amount ΔP is equal to or less than a predetermined value, the predicted voltage stabilization control may be prohibited.

Next, Example 2 of the present invention will be described with reference to FIG. However, the description of substantially the same part as that of the first embodiment will be omitted or simplified, and the part different from the first embodiment will be mainly described.

In the second embodiment, by executing the system voltage control routine of FIG. 6 described later by the motor control circuit 32, the predicted voltage stabilization control is executed only when the predicted system voltage change occurs in the rising direction of the system voltage. I am trying to do it. The system voltage control routine of FIG. 6 is obtained by changing the processing of step 102 of the system voltage control routine of FIG. 2 described in the first embodiment to the processing of step 102a, and the processing of each step other than this is Same as Figure 2.

In the system voltage control routine shown in FIG. 6, first, in step 101, the predicted system voltage change amount ΔV is calculated based on the motor power change amount ΔP, and then the process proceeds to step 102a to proceed to the predicted system voltage change amount ΔV (or motor power). Whether or not the predicted system voltage change is in the decreasing direction of the system voltage is determined based on whether or not the amount of change ΔP) is smaller than a predetermined value (for example, 0).

If it is determined in step 102a that the predicted system voltage change is in the downward direction of the system voltage, it is determined that there is no possibility that the system voltage will become excessive, and the process proceeds to step 103 to proceed to the predicted system voltage change. Forcibly set the quantity ΔV to 0 so that the predicted voltage stabilization control is not executed.

On the other hand, if it is determined in step 102a above that the predicted system voltage change is in the upward direction of the system voltage, it is determined that the system voltage may become excessive and an overvoltage may be applied to the electronic device. Then, skip the process of step 103, proceed to step 104, and use the predicted system voltage change amount ΔV when calculating the F / F control amount Duty.ff (= Vb /Vsys.tar) of the boost converter 14. Correct the target value Vsys.tar of the system voltage and correct the F / F control amount Duty.ff of the boost converter 14.

As a result, the predicted system voltage change amount ΔV is reflected in the F / F control amount Duty.ff of the boost converter 14 to execute the predicted voltage stabilization control. However, when the predicted system voltage change amount ΔV = 0, the predicted voltage stabilization control is not executed.

After that, after calculating the feedback control amount Duty.fb of the boost converter 14, it is the final control amount of the boost converter 14 using the F / F control amount Duty.ff and the F / B control amount Duty.fb. Calculate the energization duty ratio Duty (steps 105, 106).

In the second embodiment described above, the predicted voltage stabilization control is executed only when the predicted system voltage change occurs in the upward direction of the system voltage. Therefore, the system voltage becomes excessive and the electronic device becomes overvoltage. It is possible to avoid executing the predicted voltage stabilization control more than necessary while surely preventing the application.

In the above Examples 1 and 2, when the F / F control amount Duty.ff of the boost converter 14 is corrected by using the prediction system voltage change amount ΔV, it is used to calculate the F / F control amount Duty.ff. The target value Vsys.tar of the system voltage is corrected by the predicted system voltage change amount ΔV, but the input voltage Vb used to calculate the F / F control amount Duty.ff can be corrected by the predicted system voltage change amount ΔV. The correction method of the F / F control amount Duty.ff may be changed as appropriate.

Next, Example 3 of the present invention will be described with reference to FIG. 7. However, the description of substantially the same part as that of the first embodiment will be omitted or simplified, and the part different from the first embodiment will be mainly described.

In each of the above Examples 1 and 2, the predicted voltage stabilization control is executed by correcting the F / F control amount Duty.ff of the boost converter 14 using the predicted system voltage change amount ΔV. In Example 3, the motor control circuit 32 executes the system voltage control routine of FIG. 7, which will be described later, and corrects the F / B control amount Duty.fb of the boost converter 14 using the predicted system voltage change amount ΔV. Prediction system The voltage change amount ΔV is reflected in the F / B control amount Duty.fb of the boost converter 14 to execute the predicted voltage stabilization control.

The system voltage control routine of FIG. 7 is obtained by changing the processing of steps 104 and 105 of the system voltage control routine of FIG. 2 described in the first embodiment to the processing of steps 104a and 105a, and each of the other routines. The step processing is the same as in Figure 2.

In the system voltage control routine shown in FIG. 7, first, the predicted system voltage change amount ΔV is calculated based on the motor power change amount ΔP, and then whether or not the absolute value of the predicted system voltage change amount ΔV is equal to or less than a predetermined value is determined. If it is determined that the absolute value of the predicted system voltage change amount ΔV is equal to or less than a predetermined value, the predicted system voltage change amount ΔV is forcibly set to 0 to prohibit the predicted voltage stabilization control (step 101). ~ 103).

After that, the process proceeds to step 104a so that the output voltage of the boost converter 14 becomes the target value Vsys.tar of the system voltage based on the output characteristics of the boost converter 14 (for example, the relationship between the input voltage, the output voltage, and the energization duty ratio). The F / F control amount Duty.ff of the boost converter 14 is calculated using the input voltage Vb of the boost converter 14 and the target value Vsys.tar of the system voltage. Duty.ff = Vb /Vsys.tar

After that, the process proceeds to step 105a, and the F / B control amount Duty.fb of the boost converter 14 is calculated by PI control or PID control so as to reduce the deviation between the system voltage detection value Vsys.cur and the target value Vsys.tar. To do. At this time, the F / B control amount Duty.fb of the boost converter 14 is corrected by correcting the detected value Vsys.cur of the system voltage using the predicted system voltage change amount ΔV by the following equation. Duty.fb = f {(Vsys.cur + ΔV) -Vsys.tar}

As a result, the predicted system voltage change amount ΔV is reflected in the F / B control amount Duty.fb of the boost converter 14 to execute the predicted voltage stabilization control. However, when the predicted system voltage change amount ΔV = 0, the predicted voltage stabilization control is not executed. After that, the process proceeds to step 106, and the energization duty ratio Duty, which is the final control amount of the boost converter 14, is calculated using the F / F control amount Duty.ff and the F / B control amount Duty.fb.

In the third embodiment described above, the predicted voltage stabilization control that stabilizes the system voltage is executed by correcting the F / B control amount Duty.fb of the boost converter 14 using the predicted system voltage change amount ΔV. Therefore, almost the same effect as that of the first embodiment can be obtained. Also in the third embodiment, the predicted voltage stabilization control may be executed only when the predicted system voltage change occurs in the upward direction of the system voltage.

Further, in each of the above-mentioned Examples 3, the system voltage used for calculating the F / B control amount Duty.fb when the F / B control amount Duty.fb of the boost converter 14 is corrected by using the prediction system voltage change amount ΔV. The detected value Vsys.cur of is corrected by the predicted system voltage change amount ΔV, but the target value Vsys.tar of the system voltage used to calculate the F / B control amount Duty.fb is corrected by the predicted system voltage change amount ΔV. The correction method of the F / B control amount Duty.fb may be changed as appropriate.

Further, in each of the above Examples 1 to 3, only one of the F / F control amount Duty.ff and the F / B control amount Duty.fb of the boost converter 14 is corrected by using the prediction system voltage change amount ΔV. Prediction voltage stabilization control is executed, but the prediction system voltage change amount ΔV is used to correct both the F / F control amount Duty.ff and the F / B control amount Duty.fb of the boost converter 14 for prediction. The voltage stabilization control may be executed.

Further, in the above Examples 1 to 3, when the power change amount ΔPmg1 of the first motor drive unit 21 and the power change amount ΔPmg2 of the second motor drive unit 22 are obtained, they are based on the torque command value of the AC motor. The amount of change in the power of the motor drive unit is calculated, but it is not limited to this, and it is based on the command value of the control amount other than the torque command value of the AC motor (for example, the voltage command value or the current command value of the AC motor). The amount of change in the power of the motor drive unit may be obtained.

Alternatively, the amount of change in the power of the motor drive unit may be obtained based on the current detection value of the AC motor. Specifically, the torque is calculated based on the current detection value of the AC motor, the power of the motor drive unit is calculated based on this torque and the rotation speed, and the difference between the power calculated this time and the power calculated last time is calculated. By calculating, the amount of change in the power of the motor drive unit per predetermined time is obtained. Since the current detection value of the AC motor is data that accurately reflects the actual power of the motor drive unit, the amount of change in the power of the motor drive unit can be calculated accurately by using the current detection value of the AC motor. .. Not limited to this, the power change amount of the motor drive unit may be calculated based on the detected value of the control state other than the current detected value of the AC motor.

In addition, the present invention is not limited to a hybrid vehicle powered by an AC motor and an engine, and the present invention may be applied to a vehicle powered only by an AC motor. Further, the present invention may be applied to a vehicle equipped with only one motor drive unit including an inverter and an AC motor or a vehicle equipped with three or more motor drive units.

<figref num="1">It is a schematic block diagram of the whole motor control system in Example 1 of this invention.</figref><figref num="2">It is a flowchart explaining the process flow of the system voltage control routine of Example 1.</figref><figref num="3">It is a flowchart explaining the process flow of the system voltage change prediction routine of Example 1.</figref><figref num="4">It is a figure explaining the relationship between the motor power change amount and the system voltage change amount.</figref><figref num="5">It is a figure which conceptually shows an example of the map of the prediction system voltage change amount.</figref><figref num="6">It is a flowchart explaining the process flow of the system voltage control routine of Example 2.</figref><figref num="7">It is a flowchart explaining the process flow of the system voltage control routine of Example 3.</figref>

Code description

11,12 ... AC motor, 13 ... DC power supply, 14 ... Boost converter (voltage conversion means), 15 ... Power supply line, 17 ... Smoothing capacitor, 18,19 ... Inverter, 20 ... Voltage sensor, 21,22 ... Motor drive unit, 23,24 ... Rotor rotation position sensor, 32 ... Motor control circuit (system voltage change prediction means, system voltage control means), 33 ~ 36 ... Current sensor