| Abstract |
This paper presents a modified control system for voltage type PWM AC to DC converters based on Input-Output linearization. This system is based on the direct control of two quantities: the DC capacitor voltage, via the direct current and reactive power. Two hysteresis current controllers in rotating frame co-ordinates are used as the inner loop. The method can be used also with other current controllers. An outer non-linear controller based on the input-output linearization sets the direct reference current. The synthesis of the DC voltage controller is done using some approximations. The control system presents high performances and is useful for inverter or rectifier operations. The major drawback, compared with other methods, is the need of a load current sensor. To solve this drawback a modified control system is presented in this paper. The load current is obtained using the DC current of the converter that can be easily obtained with the AC currents, the switching states of the semiconductor devices and the reference current of the capacitors. |
