Bipolar Power Supply Voltage Balancing for Neutral Wire Current Control
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Solution Overview
Problem
In bipolar power supply systems, uncontrolled neutral wire current can exceed cable specifications, affecting system reliability and reducing energy yield, especially in scenarios like wind and photovoltaic power systems where positive and negative voltage conversion apparatuses have different maximum output powers.
Innovation Solution
A controller adjusts the output voltages of the positive and negative voltage conversion apparatuses to maintain unchanged output power while controlling the neutral wire current within a preset range, using control units to increase or decrease voltage differences as needed to manage the neutral wire current effectively.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If separate power supplies are used for positive and negative polarities, then isolation and safety are improved, but device complexity and space requirements increase
Solution Approach 1:
The patent combines separate positive and negative power supplies into a single integrated power supply unit. The controller manages both polarities within one device, reducing component count and simplifying the overall system architecture while maintaining the functional separation needed for safety and isolation.
Solution Approach 2:
The single power supply unit is designed to provide multiple functions: generating both positive and negative voltages, isolating different circuits, and controlling various operational modes. This multi-functional design eliminates the need for separate dedicated power supplies for each polarity while maintaining safety requirements.
2Reliability
If separate power supplies are used for positive and negative polarities, then circuit isolation is improved, but the physical space and cost increase
Solution Approach 1:
The patent integrates multiple power supply functions into a single physical unit that occupies less space than separate power supplies would require. The unified design shares common components and housing while maintaining electrical isolation between positive and negative output circuits.
3Ease of operation
If analog switches are used for polarity switching, then switching capability is improved, but high-frequency noise and signal loss increase
Solution Approach 1:
The patent replaces analog mechanical switches with digital switching mechanisms controlled by a microcontroller. This substitution eliminates the high-frequency noise and signal loss associated with analog switch contacts, while maintaining the polarity switching capability through digital control signals that drive solid-state switching elements.
4Device complexity
If a single power supply is used for both polarities, then device complexity is reduced, but isolation between circuits deteriorates
Solution Approach 1:
The patent merges positive and negative power supply functions into one unit while incorporating internal isolation mechanisms. The single power supply includes separate winding sets or isolated DC-DC converter stages that maintain electrical isolation between the positive and negative output circuits, preventing ground loops and interference while simplifying the external system architecture.
Data Source
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AI summary
A bipolar power supply system and a control method are provided, to improve management efficiency of controlling a neutral wire current. The bipolar power supply system includes a voltage conversion unit, an inverter unit, and a controller. The voltage conversion unit includes a positive voltage conversion apparatus and a negative voltage conversion apparatus. The inverter unit includes a positive inverter and a negative inverter. A negative output end of the positive voltage conversion apparatus and a positive output end of the negative voltage conversion apparatus are connected to a first end of a neutral wire, and a negative input end of the positive inverter and a positive input end of the negative inverter are connected to a second end of the neutral wire. The controller is configured to: detect whether a neutral wire current meets a preset current range; and control, when the neutral wire current does not meet the preset current range, the positive voltage conversion apparatus and the negative voltage conversion apparatus to change output voltages when output power remains unchanged, so that the neutral wire current meets the preset current range.