Voltage sensorless predictive direct power control of three‐phase PWM converters

Abstract

This study develops a voltage sensorless predictive direct power control (PDPC) strategy for three-phase pulsewidth modulation (PWM) converters using accurate virtual flux (VF) estimation. This proposed PDPC can realise simultaneous control of the instantaneous active and reactive power, and achieve a constant switching frequency operation by adopting an on-line corrective space vector modulation modulator. AC voltage sensors are removed by using the following two techniques. One is that an accurate VF observer is employed to compensate the magnitude and phase errors introduced by the first-order low pass filter. The other is that grid voltages are estimated using the VF based estimation of instantaneous active and reactive power as intermediate variables. In addition, the time delay existing in a real system is taken into account in the proposed control model. Comparative results demonstrate the excellent performance of the proposed approach compared with the conventional look-up-table DPC and the conventional PDPC.

Sliding mode observer‐based AC voltage sensorless model predictive control for grid‐connected inverters

“…In [14][15][16][17][18], virtual-flux based AC voltage sensorless control methods are studied. Conventionally, pure integration operation is required to estimate the virtual-flux.…”

“…Thus, many improved virtual-flux observation methods were further proposed. In [14,15], virtual-flux is estimated using a first-order low-pass filter instead of the pure integrator. However, magnitude and phase errors will be generated because of the differences between the pure integrator and the low-pass filter.…”

Grid Voltages Estimation for Three-Phase PWM Rectifiers Control Without AC Voltage Sensors

“…Despite its simplicity, the AC-line currents derivative is required. Since this solution presents high noise sensitivity, other methods have been developed using virtual flux (VF) concept [9], [10], [16]- [21], Kalman filters [22], [23], disturbance observers [14], [24], hybrid parallel observers [25] and Luenberger observers [26]. Adaptive fullorder observers [12], [27] have been also proposed for grid voltage sensorless control.…”

Remote Power Control Injection of Grid-Connected Power Converters Based on Virtual Flux

“…In [8,9], a comparison of the voltage-based control and the VF-based control both working in DPC and VOC were presented. A few examples of the virtual flux working only in DPC mode have been presented in the literature [10][11][12][13] while the work presented in [14] is an example of the work related to virtual flux implementation in the VOC strategy.…”