Design Of Control System For Digital High-Voltage DC Power Supply

Nowadays, the requirement of the power supply is increasing, which makes the traditional High-Voltage DC Power Supply no longer meet the people’s demand for the reason of its big volume, high harmonic level and great impact on pollution for grid.While with the development of power semiconductor devices, power devices and digital chips, increasing attention has been paid on digital High-Voltage DC Power Supply since it has the advantage of small size, high efficiency and light weight compared with traditional High-Voltage DC Power Supply. As a consequence, the traditional High-Voltage DC Power Supply has been taken placed by the digital one.This thesis is aimed at designing a control system of digital High-Voltage DC Power Supply. This system consists of two parts. Part one is AC-DC converter which converts the 220V-three-phraseAC signal into 720V DC signal. DC-DC converter is part two, which converts the above 720V DC signalinto-80kV DC voltage. Modular design concept, which is convenient to the maintenance and expansion, is adopted-the two converters are separately controlled by their own DSP.According to the requirement and performance of High-Voltage DC Power Supply, thedouble-loop PI control,together with the three-phase-voltage-PMW rectifying technology, is applied to control the current at AC sideand the output of Voltage at DC side of the AC-DC convertor. And the single-loop PI control,with the PFM technology, is applied in the DC-DC convertor to control High-Voltage Power Supply to output a stable DC voltage.In this thesis, the control algorithm is given,thenthe AC-DC and DC-DC convertor are modeled and simulated with the control algorithm inSimulink.The result of simulation shows that the performance of system can meet the requirement of this system.In this thesis, the TMS28335-DSPof TI is used as the core controller to design the hardware circuit of the High-Voltage DC Power,including DSP minimum circuit, IGBT driving and protecting circuit, circuit for acquisition of current and voltage and circuit for photon coupled isolator.With the base of the hardware circuit,software is accomplished with the platform of CCS to realize such functions as data acquisition, abc-dq coordinate transformation and inverse transformation, control of PI regulator and control the generation of pulse signal.A test platform is built to test its reliability.The result of the test shows that the linear optical circuit for data acquisition has both good linearity and good electric isolation, and AC-DC converter can reach a power factor up to 98.62%. What’more, the harmonic of input AC current is only 4.2385%, and the output voltage of Power Supply can reach the -80kv’s target with subtle fluctuation.