Adaptive tolerance-band current control of standby power supply provides load-current harmonic neutralization

The authors present a standby power supply system which provides the combined functions of power backup and load current harmonic neutralization. The system is based on a four-switch insulated gate bipolar transistor (IGBT) inverter which is operated in either a voltage or a current mode. The voltage mode uses traditional fixed-frequency pulse width modulation control. The current mode uses an adaptive tolerance band scheme to achieve fixed-frequency. The authors discuss the design tradeoffs for the current-mode control, and present performance data for a 120 V, 25 A (peak) single-phase system.<
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