Wu Guoliang

A simple diagnosis of winding short-circuited fault of PMSM for electric vehicle

The negative-sequence current analysis is a classical method of single phase winding short in the PMSM. In this paper, a simple method is presented for on-line winding short circuit fault detection. It consists of a new calculation of negative sequence current based on negative-rotating synchronous reference frame. The amplitude of negative-sequence current is used as the indicator reflecting the severity of inter-short fault. The fault-detecting method is implemented very easily for electric driving system based on vector space control. A simulation is presented to verify the application proposed method.

Power quality control technology based on customer power

In order to reduce the effect of power quality problems on precise and complicated electrical equipments, on the basis of summing up the shortcomings of SVC, APF and other devices, this paper analyzes the advantages of universal power quality compensator in improving power quality. The basic structure and operation principle of universal power quality compensator is introduced. According to the thought of ordinates transformation in electrical machinery, a strategy of detecting voltage and current based on instantaneous reactive power theory is put forward and the algorithm of compensation signal is designed. The strategy could make the input current keep sinusoidal and electrical load get standard voltage. The results show that the strategy can reduce pollution of nonlinear electrical equipments to power grid, improve power quality and provide stable and reliable green power supply for electrical devices.

Power quality analysis and harmonic suppression of high latitude and high alpine region electric vehicles charging station

In China, the first electric vehicles charging station of high latitude and high alpine region was built in Heilongjiang Electric Power Research Institute. In this research, electric vehicles charging station was introduced including a 100 kW DC charger and the main circuit diagram of EV charging station. In order to improve power quality and suppress harmonic, a shunt active power filter was applied in the EV charging station. To verify the effect of the shunt active power filter, charging experiments under different current for a bus were undertaken.

Control voltage of DC energy storage unit in universal power quality compensator based on ZVT-PWM

Supply power for DC energy storage unit by rectifier circuit produced harmonic and decreased power factor. Active power factor correction (APFC) resolved these problems, but this kind of hard switching circuit produced much consumption. It proposed a strategy that using soft switching power transformation technology to control switching devices. An improved scheme based on zero voltage transition (ZVT) PWM converter was presented and corresponding circuit was designed. The dynamic operation courses of circuit and switching states of power devices were researched. The strategy realized zero voltage transition by controlling power devices. Main switching device was conducted and turned off when voltage of resonance network was zero. The results have verified validity and feasibility of the strategy. It can decrease power consumption of switching devices, reduce harmonic, improve power factor and further perfect operation performance of universal power quality compensator.