Pwm-controlled power supply including choke coil with 3 windings

In a PWM control type power supply apparatus (100), a modulation (high frequency) signal component is eliminated not only from AC input, but also AC output. The PWM control type power supply apparatus (100) includes: AC-to-DC converting means (2:3) capable of supplying a first AC voltage having a source frequency from a pair of output terminals, for converting the first AC voltage to obtain a positive DC (direct current) voltage from a positive half cycle and a negative DC voltage from a negative half cycle of the first AC voltage appearing at one output terminal with a common voltage appearing at another output terminal; DC-to-AC inverter means (6:9) including a pair of first and second switching elements (63:64), and a PWM (pulse width modulation) controller (9) for controlling switching operations of the first and second switching elements (63:64) in a PWM control mode so as to invert the positive and negative DC voltage into a second AC voltage having a modulation frequency higher than the source frequency said second AC voltage being applied to a load (8); and, chalk coil means (10) having a single core and first, second and third coil windings (101:102:103) wound on said single core for magnetically coupling said coil windings with each other, said first and second coil windings (101 and 102) being interposed between said AC power source (1) and said AC-to-DC converting means (2:3), and also said third coil winding (103) being interposed between said DC-to-Ac inverter means (6:9) and said load.