Control circuit for AC=DC pulse width modulation converters - uses real and imaginary components of incoming 3-phase supply to generate control signals for PWM unit

摘要

The voltage control circuit (7) produces a real reference current Ip1 based on the difference between the reference voltage V1 and the voltage across the smoothing capacitor (4) as derived by the voltage detection circuit (6). The current detector circuit uses the sinusoidal reference values (IR, IT) derived from the current detectors (12R, 12T) together with the phase reference (psiPS) obtained from the phase detector (8) to calculate real and imaginary current components (IP, IQ). These two signals are subtracted from the real reference current and used by the effective current control circuit (14) and the reactive current control circuit (15) to produce real and imaginary voltage reference signals ep1 and eo1 which are passed to the PWM control circuit (16). The latter combines these reference signals with the psiPS signal from the phase detection circuit to produce switching signals (SW) for the PWM converter. ADVANTAGE - DC to AC feedback control enables accurate governing of pulse width modulator.