Research On The AC Current Sensorless Control Scheme Of Three-Phase PWM Rectifier

In this paper, mathematic models of the three-phase PWM rectifier are separately set up in three-phase stationary coordinate, two-phase stationary coordinate and two-phase synchronously rotating coordinate, and some kinds of control scheme for three-phase PWM rectifier are studied and compared, then the design of control system is discussed.For normal control, ac voltages sensor, ac currents sensor and dc voltages sensor are needed to control ac currents and dc voltage. By using all of these sensors, we can get the current and voltage parameters very quickly, however, it also makes the system bulky and expensive. In addition, the sensing signals incidental missing may deteriorate the reliability. Hence improvements are needed. In this paper, three kinds of ac current sensorless control scheme are given, which are based on dc-link current detecting control scheme, based on dc-voltage detecting control scheme and based on state space averaging technique control scheme. Besides, the first two controll scheme is simulated by the Simulink of Matlab.On the basis of the theory analysis of three-phase PWM converter, a resolving strategy based on TMS320F2812 without ac current sensor for converter control system is proposed, including software design and hardware design. Meanwhile, an experiment prototype has been made and experiment has been performed. Finally, some testing results are shown.