可変インピーダンスとしてのリニア発電機用PWMコンバータの制御

抄録

We are developing a linear generator system as an onboard power source for Maglev vehicles. This linear generator system mainly consists of power collecting coils and has a Pulse Width Modulated convertor that functions as an impedance to compensate for reactive power in the generator circuit. The PWM convertor detects only instantaneous currents and realizes unity power factor control with excellent performance. Nevertheless, the measured impedance of the circuit differs from that estimated from the parameters of PWM convertor. The system becomes unstable when we set certain impedance values for the PWM convertor.
We analyzed the control system as a closed loop digital control system and we derived impedance realized in the circuit We also obtained stable areas of impedance and currents from the conditions of stability of digital control system. The analyzed results of stability were in agreement with simulation results.