Model predictive control (MPC) has been proposed as an effective method for power control of PWM rectifier. It achieves good steady state performance and quick dynamic response under the condition of balanced and sinusoidal three-phase grid voltages. However, for unbalanced and distorted network, conventional MPC presents highly distorted grid currents if no special measure is taken. Furthermore, the use of grid voltage sensors increases the system cost and reduces the system reliability. This paper proposes a grid-voltage sensorless MPC method for the control of PWM rectifier. It uses the extended reactive power instead of conventional reactive power to cope with the unbalanced grid voltage conditions. Furthermore, the concept of virtual flux is introduced to achieve grid-voltage sensorless operation and can work effectively even under distorted network. Different from prior methods, the estimation of the virtual flux is obtained from a second-order generalized integrator quadrature signal generator (SOGI-QSG) in combination with a cascaded delayed signal cancellation (CDSC) block. As a result, constant active power and extended reactive power as well as sinusoidal grid currents are obtained under unbalanced and distorted network conditions with the absence of grid voltage sensors. The effectiveness of the proposed method is confirmed by the presented experimental results.
展开▼
