Research On UPQC Constant Frequency Hysteresis Control Strategy Based On Voltage Space Vector

Power is the main energy of modern society, which is widely used in all walks of life. And the national economy relates to the quality of power directly. With the increment of non-linear components of load, the grid structure is more and more complex, and the situation that various problem of power quality occur simultaneously will be more common. The United Power Quality Conditioner (UPQC), which possesses the ability of comprehensive compensation, becomes research focus gradually.On the basis of preliminary work of this topic, we studied domestic and foreign research results, analyzing the problems and solutions of power quality. Though analyzing research status of UPQC topology, detection methods of compensation and control strategy, we can get necessity of this paper against disadvantages of the existing method. For the problem that we can’t detect the compensation accurately based on p - q and i_ p - i_q of transient reactive power theory under the circumstance of voltage distortion, this paper proposes a detection method of compensation signal based on synchronous coordinate transformation, which can solve the problem effectively. In addition, in order to extend effective compensation time and reduce cost of the energy storage unit, optimizing exchange process of active power between serial converter and system. In this paper, minimum energy compensation method is adopted, and its effectiveness is verified through simulation.Traditional hysteresis loop tracking control is simple and widely used. But the non-constant of switch frequency leads to great loss. In the new algorithm, we can make the frequency constant by changing the Hysteresis width, and then for the problem of interphase interference in three-phase three-wire system, constant frequency hysteresis tracking control method based on space voltage vector is proposed, meanwhile, the problem that switch frequency is unstable and the controlled variable is uncontrollable during transposition of load is solved, its feasibility is verified through simulation.At last, we build the main circuit and design the signal detection and conditioning circuits, power circuit, circuit that produces periodic signal, drive circuit and so on, the harmonic current compensation on parallel side of UPQC is achieved after compensation testing procedure, IIR digital filtering procedure and control algorithm procedure is programmed by C language.