Resonant Auxiliary Power Circuit for Fast Voltage Balancing
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Solution Overview
Problem
Conventional medium-voltage DC power supply systems require external power for auxiliary supplies due to high insulation needs, leading to increased circuit volume and cost, and existing voltage balance circuits are unable to perform rapid voltage balance control.
Innovation Solution
An auxiliary power circuit with an even number of primary-side and secondary-side circuits, each including switches and resonance tanks, allows energy storage units to naturally transfer energy based on voltage levels, using induction units and rectification circuits to recycle excess energy efficiently.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If external power supply is used for auxiliary power supply in medium-voltage DC power supply system, then insulation capability requirements are reduced, but circuit volume and cost increase due to additional power supply equipment
Solution Approach 1:
The auxiliary power supply uses self-powered configuration where the auxiliary power supply unit obtains power from the medium-voltage DC input through the conversion module, eliminating the need for external power supply equipment and reducing circuit volume while maintaining insulation capability
Solution Approach 2:
The conversion module serves dual functions: it performs power conversion for the main system and simultaneously provides power to the auxiliary power supply unit, eliminating the need for separate power supply equipment and reducing overall circuit volume
2Reliability
If voltage balance circuit is added to maintain voltage balance of capacitors in self-powered auxiliary power supply, then overvoltage protection is achieved, but circuit volume and cost increase
Solution Approach 1:
The voltage balance function is integrated into the existing conversion module and auxiliary power supply circuitry, sharing components such as the resonance tank and switching units, thereby achieving overvoltage protection without adding separate balance circuit equipment and reducing overall circuit volume
Solution Approach 2:
The conversion module performs multiple functions including power conversion, auxiliary power supply, and voltage balance control, eliminating the need for dedicated balance circuit equipment and reducing circuit volume
3Reliability
If conventional voltage balance circuit is used, then voltage balance is maintained, but rapid voltage balance control capability is insufficient
Solution Approach 1:
The circuit employs dynamic resonance-based energy transfer between capacitors through controlled switching, enabling rapid voltage balance control compared to conventional static balance circuits, as the resonance oscillation quickly redistributes energy to equalize voltages
Solution Approach 2:
The switching units operate in periodic resonance cycles to transfer energy between capacitors, achieving rapid voltage balance through repeated energy oscillation and redistribution, which is faster than conventional continuous regulation methods
4Extent of automation
If isolation transformer with medium voltage isolation capability is used, then auxiliary power supply can be self-powered, but device complexity and cost increase
Solution Approach 1:
The isolation transformer is removed from the system and replaced with a resonance-based isolation approach where galvanic isolation is achieved through magnetic coupling in the resonance tank without requiring a traditional isolation transformer, thereby reducing device complexity while maintaining self-powered capability
Solution Approach 2:
The mechanical/electromagnetic isolation transformer is replaced with a resonance-based magnetic coupling system that achieves both isolation and power transfer through resonant oscillation, simplifying the overall system structure while maintaining self-powered operation
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This solution enables faster response times and reduces power loss by allowing energy to be recycled within the system, eliminating the need for resistors and minimizing circuit volume and cost.
Implementation Method 1
Each primary-side circuit includes a first switch unit, a second switch unit, and a resonance tank. The resonance tank is coupled in parallel to the second switch unit.
Implementation Method 2
The secondary-side circuit includes at least one induction unit and a rectification circuit. The at least one induction unit is coupled to the two resonance tanks of the two primary-side circuits.
Implementation Method 3
The rectification circuit is coupled to the at least one induction unit and the control unit, and rectifies a power provided by the at least one induction unit into a DC power and supply the DC power to the control unit.
Data Source
AI summary
An auxiliary power circuit of a conversion module is used to supply power to a control unit, and an input end of the conversion module includes an even number of energy storage units coupled in series. The auxiliary power circuit includes an even number of primary-side circuits and a secondary-side circuit. Each primary-side circuit includes a first switch unit, a second switch unit, and a resonance tank. The first switch unit is connected to the second switch unit in series, and is correspondingly connected to one of the energy storage units in parallel. The resonance tank is connected to the second switch unit in parallel. The secondary-side circuit is coupled to the resonance tanks of two of the primary-side circuits to acquire power and supply power to the control unit.