Research on Voltage Stability of Grid-Connected Photovoltaic System Based on Double-Side Voltage Feedback Control
In terms of the problem that the grid-connected photovoltaic DC system is unstable during low voltage ride through (LVRT), an improved double-side voltage control strategy is proposed. The voltage feedback control is introduced in the front converter circuits to form a hybrid control including volta...
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| Main Authors: | , , , |
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| Format: | Article |
| Language: | zho |
| Published: |
State Grid Energy Research Institute
2022-09-01
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| Series: | Zhongguo dianli |
| Subjects: | |
| Online Access: | https://www.electricpower.com.cn/CN/10.11930/j.issn.1004-9649.202202014 |
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| Summary: | In terms of the problem that the grid-connected photovoltaic DC system is unstable during low voltage ride through (LVRT), an improved double-side voltage control strategy is proposed. The voltage feedback control is introduced in the front converter circuits to form a hybrid control including voltage feedback and maximum power point tracking (MPPT). In addition, this paper combines the voltage feedback loop of the grid-connected inverter and comprehensively controls the grid-connected photovoltaic DC system during LVRT. Meanwhile, in order to realize the automatic balance between the voltage control and power control of the front converter, this paper designs adaptive weight coefficients of the voltage feedback loop and MPPT loop based on the actual bus voltage. To verify that the improved control strategy can stabilize the DC system during LVRT, the paper carries out a hardware-in-loop (HIL) test based on the RT-LAB platform. The test result shows that without a Chopper resistor, the double-side voltage feedback control strategy can reduce the variation of DC voltage from 136V to 60.5V during LVRT compared with the traditional control strategy, and the grid-connected impulse power can be decreased from 3 955W to 2 264W, which not only reduces the current stress of converter circuits but also improves the stability of the photovoltaic system during LVRT. |
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| ISSN: | 1004-9649 |