WPT Inverter Regulation for Wide-Range ZVS Control
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Solution Overview
Problem
Existing wireless power transfer (WPT) systems face limitations in achieving zero voltage switching (ZVS) over a wide power range, particularly due to restricted output voltage and power ranges, leading to increased switching losses and decreased efficiency.
Innovation Solution
A WPT system regulation method and system that determines phase-shift and switching frequency boundaries based on a linear state equation for an LCC-LCC compensation topology, allowing for ZVS across a wide power range by fixing switching frequencies at resonance frequencies and varying phase-shift angles, and using frequency modulation to optimize output voltage ranges.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If phase shift control is used in the WPT system, then the switching frequency is fixed and output voltage or power can be regulated, but the ZVS operation cannot be implemented when output power changes greatly, resulting in increased switching loss and decreased system efficiency
Solution Approach 1:
The patent applies dynamics by making the switching frequency adjustable rather than fixed. The system dynamically adapts the switching frequency based on the desired output power level, allowing the inverter to maintain ZVS operation across a wide power range. The controller determines appropriate switching frequency and phase shift angle combinations to achieve both the required output power and ZVS condition simultaneously.
Solution Approach 2:
The patent changes the operating parameters (switching frequency and phase shift angle) to achieve ZVS operation. By adjusting these parameters based on the desired output power, the system can maintain soft switching conditions while delivering varying power levels. The controller selects optimal parameter combinations from pre-calculated boundaries to ensure both power regulation and ZVS performance.
2Power
If frequency modulation control is used, then the switching frequency is regulated according to output power, but the adjustable frequency range is limited and cannot achieve a wide range of power output
Solution Approach 1:
The patent achieves universality by combining both frequency modulation and phase shift control capabilities in a single system. The controller can operate in different modes (frequency modulation, phase shift control, or combined mode) depending on the desired output power level. This multi-functional approach allows the system to achieve both wide frequency adjustment range and wide output power range, overcoming the limitations of using either method alone.
3Reliability
If additional auxiliary circuits are added to achieve ZVS operation, then ZVS can be implemented, but the device complexity increases and costs increase
Solution Approach 1:
The patent applies self-service by using the existing inductor current in the primary-side resonance compensation network to achieve ZVS operation without additional auxiliary circuits. The controller utilizes the natural resonant current already present in the system to provide the necessary discharge current for soft switching. This approach maintains ZVS reliability while avoiding increased device complexity and cost.
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 approach enables ZVS operation across a wider output range than conventional methods, reduces switching losses, and maintains system efficiency without the need for additional auxiliary circuits or devices, while being simple to implement.
Implementation Method 1
fixing a switching frequency at a resonance frequency of the WPT system, and determining, in a phase-shift manner, a phase-shift range and a corresponding first voltage output range for implementing ZVS
Data Source
AI summary
A wireless power transfer (WPT) system regulation method and system for implementing zero voltage switching (ZVS) in a wide power range are provided. The method includes: determining, according to a topology structure of a WPT system and based on a linear state equation, a phase -shift angle boundary and a switching frequency boundary of an inverter that meet ZVS; fixing a switching frequency at a resonance frequency of the WPT system, and determining, in a phase -shift manner, a phase-shift range and a corresponding first voltage output range for implementing ZVS; determining a frequency variation range of a frequency modulation method; determining an optimal switching frequency based on corresponding switching frequencies and phase-shift angles that meet ZVS at different expected output voltages of the WPT system; determining a second voltage output range for implementing ZVS at the optimal switching frequency; and regulating the WPT system by using different regulation methods.