| Based on the need to develop and test the products, a single phase DSP-based programmable AC power supply is designed. The power supply is capable of providing a stable AC voltage with adjustable amplitude and frequency over a wide range. Moreover, it can generate various high-quality and low-frequency arbitrary waveforms. Because of the advantages above, it will have great value in practice and a promising future in testing field.The main circuit of the power supply is to use rectifier and filter to make220V AC voltage become steady DC voltage firstly. Then the inverter and the LC LPF are employed to produce the AC voltage which is required in the test system. The key part of the inverter is phase-shift full bridge.The PS-FB-ZVS converter is widely used in the case of medium or high power levels,and it’s a hot spot of power electronic research. The two arms of which all work at zero-voltage switching condition, thus many advantages are brought out. For example,simple structure, little loss of power, convenient control,etc. But there also exists some problems, such as inherent duty cycle loss and the parasitic oscillation on the output rectifier diodes. In this paper, the reasons of these problems are analyzed, and the solutions are presented.The power supply control part is used in TI company STM32F407controller. Using high-speed calculation capability of STM32F407and event handling ability to the full bridge circuit PWM and a closed-loop control design and application.The design adopts synchronous modulation to control PWM signal output. In the synchronous modulation, by changing the event manager in the timer cycle register values to change the carrier frequency, so as to achieve the purpose of changing the output voltage to frequency. As for the value of the output voltage regulation, through adjusting system to be controlled.The design by Holzer voltage sensors to collect the output voltage signal provided to the STM32F407ADC module to realize closed loop control system. |
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