Bipolar PV Bus Redundancy Protection for Overvoltage Faults
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Solution Overview
Problem
Conventional photovoltaic power generation systems face challenges in safely managing high voltage levels, which can endanger personal safety and damage equipment, making it difficult to select suitable power devices due to increased voltage withstanding requirements.
Innovation Solution
A bipolar photovoltaic system with dual controllers and a logic circuit for redundancy protection, monitoring to-ground voltages of three direct current buses and implementing alarm signals to block driving pulses when thresholds are exceeded or controllers are faulty, ensuring voltage is maintained within safety limits.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If the voltage level of the photovoltaic system is increased, then the power generation efficiency is improved, but the voltage withstanding requirement of power devices increases making device selection more difficult
Solution Approach 1:
The patent divides the single high-voltage power supply into two separate power conversion channels (positive and negative half-cycles), each handling half of the voltage stress. The bipolar structure segments the voltage burden so that each power device only needs to withstand a portion of the total voltage, making device selection easier while maintaining high power generation efficiency.
2Power
If the input voltage of the inverter is increased beyond safety limits, then the power output is improved, but personal safety and equipment safety are endangered
Solution Approach 1:
The patent implements dual controllers that continuously monitor system parameters and provide feedback control. When overvoltage or faults are detected, the controllers automatically adjust or disconnect the power flow to maintain safe operating levels, ensuring both high power output capability and safety compliance through real-time monitoring and control.
Solution Approach 2:
The bipolar structure with dual controllers provides inherent safety margins and protection mechanisms before dangerous voltage levels are reached. The system is designed with built-in redundancy and protection circuits that activate preemptively to prevent safety hazards, rather than reacting after damage occurs.
3Reliability
If dual controllers are implemented for redundancy protection, then the system reliability is improved, but the device complexity increases
Solution Approach 1:
The patent merges the control functions of dual controllers into a coordinated bipolar system where both controllers work simultaneously on complementary half-cycles. This integration allows the system to achieve redundancy and improved reliability while managing complexity through unified bipolar control architecture rather than separate independent control systems.
Data Source
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AI summary
This application discloses a bipolar photovoltaic system, a power supply system, and a redundancy protection method. The photovoltaic system at least includes: a first output end, a second output end, and a third output end of a power converter are respectively connected to a first end of a positive direct current bus, a first end of a neutral bus, and a first end of a negative direct current bus; a first input end and a second input end of a first inverter are respectively connected to a second end of the positive direct current bus and a second end of the neutral bus; a first input end and a second input end of a second inverter are respectively connected to a second end of the neutral bus and a second end of the negative direct current bus; a first controller outputs a first overvoltage alarm signal when at least one of the following conditions is met; a second controller outputs a second overvoltage alarm signal when at least one of the following conditions is met; and the at least one condition includes: a to-ground voltage of the positive direct current bus is greater than or equal to a preset threshold, a to-ground voltage of the negative direct current bus is greater than or equal to the preset threshold, or a to-ground voltage of the neutral bus is greater than or equal to the preset threshold. In this way, timely redundancy protection is provided when a fault occurs in the system.