Research On Cophase Power Supply Balance Compensation Device Of One Cycle Control Technology

At present, electrified railway of our country is in the period of rapid development. The scale and construction of high-speed railway also appears the explosive growth in recent years. Since October 2013, our country comes up with the strategy of high-speed going out, the state council premier Li Keqiang has repeatedly promote China’s high-speed railway when he visit to other countries. Recently the hot focus "one belt and one road" strategy also puts forward China’s high-speed rail connect new silk road. It is observed that the development of electrified railway and its associated technology will face a very rare challenge and opportunity. Cophase power supply technology as a cutting-edge core technology of electrification railway, in solving the electric locomotive single-phase load caused by the negative sequence and harmonic and reactive current issues is a comparatively complete solutions, and break through the electrical phase splitting problem which is the bottleneck in the development of high-speed and heavy-load railway..Cophase power supply technology attracted much attention in recent years, and has obtained certain research achievements; its core equipment balance compensation device control technology also has the certain breakthrough. This paper briefly introduces the characteristics and structure of cophase power supply system; derives the back-to-back and three-phase bridge’s equilibrium principle of the balance of the compensation device transform, analyses the hysteresis control and voltage vector control, several commonly used control methods implementation principle of balance compensation device.This paper studies in detail in the same phase balance compensation device control technology used in cophase power supply system, which based on the simple and no accumulated error characteristics of one-cycle control technology hardware; studies the control method of back-to-back and three phase three bridge in two structure balance compensation device, which based on current reference of one-cycle control technology. According to the original cophase power supply technology instruction current generated method of foundation analysis the one-cycle control technology instruction current generating circuit, deduces the one-cycle control equation, and analysis the control circuit. For the realization of the compensating chain device with large capacity, we design two structures for the one-cycle control strategy. One of them is the three phase three bridge structure and the other is back-to-back structure, both of which are based on the three-level PWM converter. We also did careful analyses for its control theory. And managed to apply the one-cycle theory to the compensating chain device with large capacity in the cophase traction power supply system.Using MATLAB/Simulink simulation and modeling, this paper gives a brief analysis of the effect of several common control technologies under the "AC-DC" electric locomotive load conditions. This paper analysis the effect of single-cycle control technology under the same load conditions specifically, and simulation results show that single-cycle control technology can guarantee that compensation balun can achieve the same effect, verifying the feasibility of the control technology of a single-cycle.