Design Of The Power Quality Controller And Simulation Study About The Power Quality Controller's Application

As the development of science and technology the higher quality of electrical power is required by users. Meanwhile, more and more nonlinear loads adopted in the power system deteriorate it. It has been a key research field in power electronic application technology to study the power quality controller to compensate the reactive current and harmonic current caused by the nonlinear devices. At the present time, correlative study about the power quality is becoming the hotspot,and the controllable technology of the power quality is also developing quickly at the overseas. However,at home the study of the power quality is almost localized at the range of the theory and the trial about merely the study of the harmonic questions. there are great gap about the control of the power quality between at home and at the overseas.Shunt voltage controller of power quality will be deeply studied in this paper to restrain harmonic current, compensate reactive power and keep symmetry of the current of the power source. A practical control device of electrical power quality is developed.The integral structure is decided through the studying operating principle of shunt voltage controller of power quality. The detection method of current based on the instantaneous var power: i_p—i_q is deeply studied. This method is adapted to detectcurrent when power source voltage is distorted. In this paper the control strategy of current tracking and comparison is adopted. In order to reduce harmonic current caused by the compensation device that the control method of triangular wave comparison is adopted. The structure of power quality controller(PQC) mentioned in this paper is available through building the simulink model of PQC based on the Matlab software.Moreover, the simulink model of PQC is used to prove the practical effection of the method of detecting current and the control manner of triangular wave comparison.The result indicates that the method of detecting current and the control manner of triangular wave comparison is adapted to the PQC s structure adopted in this paper.Nowadays, there is not definite algorithm to determine the main circuit capacitor inDC side and inductance in AC side. An estimation algorithm is proposed in this paper to determine the range of the capacitor and the inductance. The inductance is sensitive to the result of compensation, after that, large quantity simulation is need to decide the inductance value at last. In addition, as PQC compensates the distortion current, itself will cause some power loss and reduce the voltage of capacitor in DC side. To compensate this reduction ,a linearization method is proposed which can charge the capacitor in DC side to keep its voltage in defined range as well as compensate harmonic current.The hardware circuit of power quality controller based on DSP is designed. Except to compensate distorted current, the device can protect the switch devices from short circuit and detect DC voltage. In addition the communication function is designed in this device and enough expansion ports are provided to convenient the device upgrading later.Part programme have been finished through project program method.At last, the distorted current caused by electrical resistance furnace in a factory is selected as compensation object.,The simulation model of electrical resistance fumace is built,in addition,the author also build the simulation'model that PQC is connected with the electrical resistance furnace. Though the simulation of the system in different operating condition the feasibility of PQC is proved.