CN-122026690-A - SOP power module dead zone effect suppression method

Abstract

The invention relates to the field of power electronic converters and control, in particular to a dead zone effect suppression method of an SOP power module, which comprises the steps of acquiring the current transmission power of the SOP power module, generating a first bus voltage command for controlling the voltage of an AC-DC side direct current bus and a second bus voltage command for controlling the voltage of the DC-AC side direct current bus based on the transmission power, adjusting the corresponding direct current bus voltage to suppress the polarity inversion of the bridge port voltage of the DAB converter, generating the first bus voltage command and the second bus voltage command according to the transmission power of the SOP power module, enabling the first bus voltage command and the second bus voltage command to be unequal during light load to form a bus voltage difference value, combining with compensation of double frequency fluctuation components in the direct current bus voltage, ensuring that the direct current bus voltages at two sides meet the condition of suppressing the polarity inversion of the DAB bridge port voltage within the dead zone time period, eliminating current zero steps, recovering soft switches, improving the voltage stability under the light load, and having no need of extra hardware or complex control, and realizing simple engineering.

Inventors

• ZHENG YOUZHUO
• MIAO YU
• WENG DI
• WU YINGSHUANG
• Xiong Jinhang
• LIU LIANG
• WANG MINGWEI
• ZHI JIAN
• YANG YU
• Yuan Xianmei
• HU TIANSONG
• ZHANG HENGRONG
• FU XINYI
• LUO JIE
• FANG MINGLI
• YANG YEKUI
• XU YUTAO
• LONG ZHI
• CAI YONGXIANG
• LI YUE
• HAO SHUQING
• LIU ANJIANG

Assignees

• 贵州电网有限责任公司

Dates

Publication Date

20260512

Application Date

20251231

Claims (10)

1. 1. A method for inhibiting dead zone effect of SOP power module is characterized by comprising, Acquiring the current transmission power of the SOP power module; Generating a first bus voltage command for controlling the AC-DC side direct current bus voltage and a second bus voltage command for controlling the DC-AC side direct current bus voltage based on the transmission power; And controlling and adjusting the DC bus voltage of the AC-DC side of the SOP power module according to the first bus voltage command, and controlling and adjusting the DC bus voltage of the DC-AC side of the SOP power module according to the second bus voltage command so as to inhibit polarity inversion of the bridge port voltage of the DAB converter.
2. 2. The SOP power module dead zone effect suppression method of claim 1, wherein the generating a first bus voltage command and a second bus voltage command based on the transmission power includes: Comparing the transmission power with a preset dead zone effect suppression threshold, wherein the dead zone effect suppression threshold is a transmission power boundary for judging whether the polarity inversion of the bridge voltage of the DAB converter needs to be suppressed or not; If the transmission power is smaller than the dead zone effect suppression threshold, judging that the system is in a light-load mode; and if the transmission power is not smaller than the dead zone effect suppression threshold, judging that the system is in a non-light load mode.
3. 3. The method of claim 2, wherein when the system is in a light load mode, generating a first bus voltage command and a second bus voltage command that are different from each other so that the DC bus voltage of the AC-DC side and the DC-AC side after adjustment are not equal.
4. 4. The method of claim 2, wherein when the system is in a non-light load mode, generating a first bus voltage command and a second bus voltage command that are equal to each other to equalize the DC bus voltages of the AC-DC side and the DC-AC side after adjustment.
5. 5. The SOP power module dead zone effect suppression method of claim 3, wherein the generating the first bus voltage command and the second bus voltage command that are not equal to each other includes: obtaining a double frequency fluctuation component in the direct current bus voltage of the SOP power module; and compensating the first bus voltage command and the second bus voltage command based on the frequency doubling fluctuation component, so that the actual direct current bus voltages at two sides of the SOP power module are in a dead zone time period, and the direct current bus voltages at two sides meet the voltage difference condition required by inhibiting the voltage polarity inversion of the bridge port of the DAB converter.
6. 6. The SOP power module dead zone effect suppression method of claim 3, wherein the generating the first bus voltage command and the second bus voltage command that are not equal to each other includes: The method comprises the steps of obtaining the current phase shift angle and dead time proportion of the DAB converter, determining the minimum bus voltage difference condition required by inhibiting the polarity inversion of the bridge voltage of the DAB converter based on the phase shift angle and the dead time proportion, and setting the relative sizes of a first bus voltage command and a second bus voltage command according to the minimum bus voltage difference condition.
7. 7. The SOP power module dead zone effect suppression method of claim 6, wherein the obtaining a current phase shift angle of the DAB converter includes: Acquiring the current transmission power of the SOP power module; and setting a phase shift angle of the DAB converter according to the transmission power.
8. 8. The SOP power module dead zone effect suppression method of claim 6, wherein the obtaining a current dead zone time ratio of the DAB converter includes: and determining the proportion of the dead time to half of the switching period based on the dead time and the switching period, and taking the proportion as the dead time proportion.
9. 9. The SOP power module dead zone effect suppression method of claim 1, wherein the SOP power module comprises an AC-DC converter, a double active bridge DAB converter and a DC-AC converter which are sequentially connected, wherein the AC-DC converter and the DC-AC converter both adopt a single-phase H-bridge structure.
10. 10. The method for suppressing dead zone effect of SOP power module as set forth in any one of claims 5-9, wherein the double frequency fluctuation component is generated by a single-phase H-bridge structure of an AC-DC side or a DC-AC side in the SOP power module during power conversion.

Description

SOP power module dead zone effect suppression method Technical Field The invention relates to the field of power electronic converters and control, in particular to a dead zone effect suppression method for an SOP power module. Background Along with the massive access of new energy, energy storage and diversified loads, the traditional power distribution network is evolving from a unidirectional radiation type passive network to a bidirectional tide complex active network, and the problems of out-of-limit voltage fluctuation, uneven tide distribution and the like caused by the transition are solved, so that the stability of a power system is reduced, and the improvement of the power supply capacity is inhibited. The traditional power distribution network relies on a mechanical switch to perform passive regulation, has low response speed and low control freedom degree, and is difficult to meet the accurate control requirements on electric energy quality, reliability and operation efficiency under the condition of high-permeability new energy access. The intelligent soft Switch (SOP) has the advantages of high control speed, continuous and adjustable power flow, no impact on-off loop, voltage reactive support and the like, is more suitable for a high-reliability demand area or a power grid containing high-proportion new energy, and improves the power supply continuity and stability, the medium-voltage SOP adopts a module cascade structure and aims to reduce the voltage withstand level of a switching device, wherein an SOP power module adopts an AC-DC, DC-DC and DC-AC three-level conversion structure, an AC-DC and DC-AC level adopts a single-phase H bridge inverter as a basic power unit, the intelligent soft switch has the advantages of modularization and easy expansion, is convenient for forming multi-level output, improves the power quality, and the DC-DC level adopts a Double Active Bridge (DAB) converter, so that the electric isolation between two side ports is realized, and the energy efficient, rapid and bidirectional transmission is realized through the inherent soft switch characteristic and high-frequency power modulation capability. In the SOP power module control process, dead time is needed to be added in order to avoid the direct connection of the switching tubes of the same bridge arm. However, the dead time affects the operation state of DAB under light load, resulting in polarity inversion and voltage drop of DAB bridge voltage, which is called dead zone effect. The dead zone effect can damage DAB soft switching conditions, threatens the voltage stability of direct current bus capacitors at two sides and increases the grid-connected current harmonic wave at an alternating current side, so that development of a dead zone effect inhibition method for inhibiting DAB bridge port voltage polarity inversion phenomenon during light load is needed. Disclosure of Invention Therefore, the invention aims to solve the technical problems that when the SOP power module is in light operation, the voltage polarity inversion and the voltage drop of the DAB bridge port are caused by dead time, so that the inductor current is interrupted, the soft switching condition is destroyed, the bus voltage stability is threatened, and the grid-connected current harmonic wave is increased. The technical problem is solved by the following technical scheme that the invention provides a dead zone effect suppression method of an SOP power module, which comprises the steps of obtaining the current transmission power of the SOP power module; Generating a first bus voltage command for controlling the AC-DC side direct current bus voltage and a second bus voltage command for controlling the DC-AC side direct current bus voltage based on the transmission power; And controlling and adjusting the DC bus voltage of the AC-DC side of the SOP power module according to the first bus voltage command, and controlling and adjusting the DC bus voltage of the DC-AC side of the SOP power module according to the second bus voltage command so as to inhibit polarity inversion of the bridge port voltage of the DAB converter. In a preferred embodiment of the method for suppressing dead zone effect of an SOP power module, the generating the first bus voltage command and the second bus voltage command based on the transmission power includes: Comparing the transmission power with a preset dead zone effect suppression threshold, wherein the dead zone effect suppression threshold is a transmission power boundary for judging whether the polarity inversion of the bridge voltage of the DAB converter needs to be suppressed or not; If the transmission power is smaller than the dead zone effect suppression threshold, judging that the system is in a light-load mode; and if the transmission power is not smaller than the dead zone effect suppression threshold, judging that the system is in a non-light load mode. In a preferred embodiment of the SOP power module