Research On Transformation Topology And Control Technology Of Medium Voltage Switching Power Supply

The beam pumping unit is the main equipment for the development and production of oilfields in China.For its reverse power generation phenomenon,the medium-voltage DC power supply oil well energy-saving group control system came into being,which eliminated the multiple cross-straight in the single-well energy-saving control.The rectification part of the frequency conversion control cabinet shares a set of rectifiers for unified power supply through the DC bus.Through the combination of the common DC bus power supply and the terminal control frequency conversion technology,the mutual sharing and recycling of the reverse power generation energy of multiple pumping units is realized.Originally powered by three-phase 1140 VAC,the voltage on the busbar after rectification is close to 1600 V,and the secondary control equipment such as the core control board and PLC in the oil well inverter control cabinet often need 24 VDC and 220 VAC power supply.This article uses this as a starting point to study and design a medium voltage switching power supply suitable for1600VDC/24 VDC.In this paper,the topology characteristics of various medium voltage switching power supplies are analyzed.Combined with practical applications,the serial-parallel double-switch forward converter is selected as the converter topology.The working mode of the topology and the voltage gain under different working modes are analyzed.The hybrid control strategy based on interleaved PWM with the same duty cycle control and double loop control is selected to ensure the converter input voltage equalization and output voltage regulation,and build The simulation model analysis and verification.Then the experimental platform of the serial-parallel double-tube forward converter is built.The main circuit of the converter,the isolated driving circuit,the detection and acquisition circuit and the auxiliary circuit are designed in turn and the appropriate device parameters and models are selected.The TMS320F28335 DSP is used as the main control board,and the platform debugging program is written by the above mixed control method.The program includes a keyboard module,a PWM control module,an ADC acquisition monitoring display,and a protection module portion.Finally,it is verified by experiments that under the unbalanced voltage equalization control of the series-parallel double-switch forward converter,the input voltage equalization reduces the voltage stress of the switching tube,and the output voltage is regulated and the voltage ring voltage equalization is achieved within a certain range.The decoupling of the ring can be applied to the oil well energy-saving group control system of medium voltage DC power supply.Finally,a preliminary analysis and research on the resonance problem encountered in the experiment was carried out.