Research On Synchronous Switch Based On Collision Suppression Mechanisms

HVC(High Voltage Compensator) system has been widely used in the field of high-voltage reactive compensation, but it also brings switching over voltage and surge current. In order to solve these problems,synchronous switch technology is used. However, contactor bounce of the permanent magnet contactor should be solved firstly. Total harmonic distortion of current(THDi) caused by contactor bounce can be as high as 50% more than the national standard and often burns the thyristor valve group. In this paper, synchronous switch technology is used to solve the problem of zero-corss-switching for permanent magnet contactor. What’s more,double-voltage driving strategy is put forward for the first time to suppress contactor bounce without changing the contactor structure parameters.At last, the author can have a good control of the permanent magnet contactor and suppress surge current to a reasonable range.Since predicting the response time of permanent magnet contactor accurately is important for its control, the author carries on statistical analysis to influence factors such as power supply voltage,temperature and so on. Then this paper also studies the influence of these factors on the switching response time dispersion. To find the best closing time points, effect of different closing phase angles is also in account. The structure of reactive compensation system is verified by simulation. What’s more,this paper also describes the application of synchronous swtich in the cutting of other types of loads.For further research on inner mechanism of contactor bounce, static simulation model of permanent magnet contactor is established by Maxwell. On this basis, this paper analyzes the relationship between electromagnetic force and displacement. On the other hand, some numerical calculation results are presented, which makes the structure of permanent magnet contactor better and we can achieve the optimal energy consumption. This paper also presents lines of magnetic force and magnetic field distribution. On the basis of this analysis, guidelines to solve the problem of permanent magnet contactor bounce are obtained from the angle of electromagnetic design.After analysing dynamic mechanism of contactor bounce, machine-electric and magnetic field coupling dynamic characteristics of movable iron core from one steady state to another steady state are obtained. In order to improve the ability to open or shut off the contactor, displacement and speed of each time are obtained by simulation and experiment, which provide algorithm foundation to inhibition of contactor bounce from control angel.Based on DSP2812, an experimental platform for synchronous switching bounce control on permanent magnet contactor is designed. It is utilized to research on the single-voltage driving control, double-voltage driving control and positive-negative-voltage driving control’s elimination on switching bounce of permanent magnet contactor. Moreover, to develop the technology of positive-negative-voltage synchronous switching control, a dynamic module of displacement, velocity and accelerated velocity is established, optimizing the responding time of positive-negative-voltage control. The experimental results show that the whole scheme can effectively eliminate the switching bounce of the contactor, achieving the zero-voltage-cross switching control of HVC.