AC voltage regulator circuit arrangement for AC motor control

摘要

The circuit arrangement includes a controllable electronic switch arrangement which switches a supplied input AC voltage respectively to an output, in time intervals which are shorter than a half period of the input voltage. The arrangement comprises a rectifier arrangement (6), whose input (4, 5) is supplied with the input voltage, and at whose DC voltage output a pulsing, preferably unsmoothened DC voltage is produced. The rectifier arrangement is connected to a static converter which comprises electronic switches, preferably IGBTs, that can be switched into a conducting or blocking state, independently of the momentary value of current and voltage. An arrangement (38) is provided for producing a PWM signal with a pulse frequency which is higher than double the frequency of the AC input voltage. The switched rectifier arrangement is formed in such way that the pulsing DC voltage is switched according to the PWM signal in form of pulses with modulated width, whose height corresponds to the current height of the DC voltage. The DC voltage is switched to the output with alternating polarity during two consecutive half periods.