Regenerative AC Drive System Based on the Three Phase Permanent Magnet Synchronous Machine

The permanent magnet synchronous machine becomes an attractive solution in the transport area providing higher power density than the induction machine. Surface permanent synchronous machine is controlled by using the field oriented control. Therefore, the maximum torque is easily obtained by setting at zero value the longitudinal stator current component, i _sd ^* . The frequently dynamic regimes of the permanent magnet synchronous machine (PMSM) decrease significantly the overall efficiency of the drive system. Taking into account that during braking or reversing period the actual drive system dissipates the energy by using a brake resistor in DC link side, the authors of this paper have proposed a regenerative drive system. In this way the energy during the dynamic regimes is recovered and delivered into the utility network. Moreover, the power quality is taken into consideration by including an adequate control in order to obtain unity power factor. The topology of the proposed power converter consists of a series AC-DC active power converter, DC link capacitor and the DC-AC power inverter. By introducing a feedforward reference of the transversal stator current (i _sq ^* ) the power balance control is achieved. As a result, the speed response of the control loops is increased, lowering the DC link capacitor value. The maximum 5 % total harmonic distortion (THD) value of the input current is attained by an appropriate design of the boost inductor. By using the DC link voltage control accompanied by an appropriate design of the DC link capacitor, the DC voltage ripple is decreased under the maximum limits. The regenerative PMSM drive is developed in the Matlab/Simulink environment software and the performances in motoring and regenerating operation modes are shown.