ARCP Converter Self-Voltage Balancing for Zero-Voltage Switching
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Solution Overview
Problem
Existing auxiliary resonant commutated pole (ARCP) converters face limitations due to mid-point voltage drift, leading to increased switching losses, reduced effectiveness of zero or near-zero voltage switching, and potential component damage. Current solutions that attempt to address these issues often require additional power hardware, increasing cost, volume, and losses, while also introducing electromagnetic interference (EMI) problems.
Innovation Solution
A zero-voltage switching ARCP-based converter with a control method that balances DC-link capacitor voltages using existing hardware. This converter comprises a main section, an auxiliary section, and a control section. The control section regulates the 'ON' and 'OFF' time intervals of the main and auxiliary switches, ensuring zero voltage switching for the main switches and zero current switching for the auxiliary switches, thereby maintaining balanced DC-link capacitor voltages.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If additional power hardware (switches and inductors) is added to address mid-point voltage drift, then voltage balancing capability is improved, but device complexity, cost, volume, and losses increase
Solution Approach 1:
The patent implements self-voltage balancing by utilizing the existing auxiliary resonant circuit components (resonance capacitors and inductors) that are already present in the ARCP converter. The control method enables these existing components to perform the additional function of voltage balancing without requiring separate dedicated hardware, thereby achieving self-service and avoiding increased device complexity
Solution Approach 2:
The auxiliary circuit components in the ARCP converter are made multi-functional: the resonance capacitors and inductors serve both their original soft-switching function and the additional DC-link voltage balancing function. This universality eliminates the need for separate balancing hardware, reducing device complexity while maintaining effective voltage balance
2Productivity
If switching frequency is increased to improve power quality and reduce passive component values, then productivity and cost-effectiveness are improved, but switching losses and heat generation increase
Solution Approach 1:
The patent applies preliminary action by ensuring that the voltage across main switches is reduced to zero before the switching event occurs. The auxiliary resonant circuit pre-charges or pre-discharges the resonance capacitors connected in parallel with the main switches, creating a zero-voltage condition that eliminates overlap between voltage and current transitions, thereby enabling lossless switching at high frequencies
Solution Approach 2:
The auxiliary resonant circuit employs periodic switching of auxiliary switches to generate oscillating current that periodically resets the voltage across main switches to zero. This periodic resonant action ensures that main switches always switch at zero voltage, maintaining zero switching losses even at high switching frequencies
3Loss of energy
If wide-bandgap devices are used to reduce overlapping time and switching losses, then switching losses are reduced, but electromagnetic interference and high dv/dt problems increase
Solution Approach 1:
The patent converts the potentially harmful high dv/dt characteristic of wide-bandgap devices into a benefit by using it to rapidly charge and discharge the resonance capacitors in the auxiliary circuit. This rapid voltage change drives the resonant current that enables zero-voltage switching, transforming the harmful high dv/dt into a useful mechanism for achieving lossless switching while still using wide-bandgap devices
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
The proposed solution reduces switching losses, minimizes EMI, and improves output power quality by maintaining balanced DC-link capacitor voltages, thus enhancing the efficiency and reliability of the converter while avoiding the introduction of new EMI problems.
Implementation Method 1
A resonance circuit turns the voltage over the switching device zero before the switching event and eliminates overlap between transition edges of voltage and current, which leads to zero switching losses
Data Source
AI summary
A zero-voltage switching ARCP-based converter that is capable of balancing its DC-link capacitor voltages and a method of balancing the voltages of the DC-link capacitors of an ARCP-based converter are disclosed herein. Each phase of the converter comprises a main section, an auxiliary section, and a control section. Main switches of the main section synthesize one or more reference voltage at the output of the phase. The auxiliary section facilitates zero voltage switching of the main switches. The control section provides gate signals for the main switches and the auxiliary switches based on the feedback signals from the converter to control the main and the auxiliary circuits. The method balances the voltages of the DC-link capacitor by utilizing ARCP-based hardware. The disclosed method minimizes switching losses and other EMI problems experienced by other converters.