Research On Cascaded H-Bridge STATCOM Based On STM32 Distributed Control

Static Synchronous Compensator(STATCOM),as an important reactive power compensation device,has shorter response time and wider operation range than traditional reactive power compensation devices.This thesis mainly studies and designs a cascaded H-bridge STATCOM device based on STM32 distributed control.Specific research includes the following aspects.Topology and control system implementation principle will be as follows.(Firstly,there is Topology and control system implementation principle.)Multi-superimposed method is used to calculate the turn-on and turn-off time of the power FET in each H-bridge to achieve the sine wave output.When the ladder-wave modulation is used,the switching device works in the fundamental frequency state with low loss and high efficiency.Due to the mutual independence of bridge bridge DC capacitor,there is the problem of equalization control,the use of cycle-level equalization control strategy,is specifically made for each cycle according to the actual output voltage of each capacitor to make a re-balanced arrangement.Aiming at the delay problem between multi-arm and main control,all the delay consistency principle is adopted,and the function of measurement,calculation and communication are completed by using the half-cycle of hysteresis during system compensation.Hardware design is the second part.The device’s distribution control part finds ST Microelectronics STM32 series chips as a control chip,to control the H bridge trigger,the information collection and information to the host as a DSP chip.The main feature of this design is that the STM32 and the host control system are placed on a unified potential,and thetrigger part of the power supply is independent of power devices potential,thus solving important issues of the multi-level power supply requiring a multi-potential,while meeting the demand of the STM32 power supply reliability;the other(In addition)due to the use of equipotential communication,compared to fiber optic communication,it is cost savings.As a multi-channel isolated power supply,the magnetic transformer is designed to reduce the power consumption of two H-bridges comparing with using a traditional driving module and solve the complicated power supply problem.In the meantime,the protection operation is more consistent.The device can work normally when the two H-bridges are disconnected from the cascade to improve the reliability of the device.The simulation model of 12 H bridge cascade was built in EMTP electromagnetic transient analysis simulation software.The simulation results show the correctness and reliability of the design.In addition,the hardware design of the 12 H bridge cascaded STATCOM is also validated experimentally,mainly to realize the inverter function.The results show that the device has realized the design function and verified the feasibility of the design.