Power Converter Voltage Gain Stabilization via Dynamic Frequency Control
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Solution Overview
Problem
Existing power converters with wireless power transfer technology experience significant deviations in voltage gain due to varying loads and coupling factors, leading to increased costs and reduced efficiency, as they rely on setting the operating frequency equal to the resonant frequency of the primary inductor and compensation capacitor, which is not always feasible in practical applications.
Innovation Solution
A power converter design that includes primary and secondary side compensation capacitors, with an operating frequency set between 0.8×fa and 1.2×fb, where fa and fb are the lower and higher resonant frequencies, respectively, to maintain a stable voltage gain across different loads, and a detect circuit and control circuit to adjust the frequency based on the DC output voltage and coupling factor deviations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If the operating frequency is set equal to the resonant frequency of the primary inductor and compensation capacitor, then the input impedance is pure resistance and reactive power is reduced, but the voltage gain deviates greatly with different loads and coupling factors
Solution Approach 1:
The patent applies dynamics by making the operating frequency adjustable rather than fixed at the resonant frequency. The control circuit dynamically adjusts the operating frequency based on detected load conditions and coupling factors, allowing the system to adapt to varying operational circumstances while maintaining stable voltage gain and minimizing reactive power.
Solution Approach 2:
The patent changes the operating frequency parameter from a fixed resonant frequency to a variable frequency within the range of 0.85 to 1.15 times the resonant frequency. This parameter change enables the system to optimize both voltage gain stability and reactive power minimization by selecting the appropriate frequency based on actual operating conditions.
2Stability of the object's composition
If elements withstanding high voltage are utilized to compensate for voltage gain deviation, then voltage gain stability improves, but costs of the power converter rise
Solution Approach 1:
Instead of using high-voltage-rated components to compensate for voltage gain deviation, the patent changes the operating frequency parameter to control voltage gain stability. This approach allows the use of standard voltage-rated components while achieving the desired voltage gain stability through frequency adjustment, thereby reducing overall system cost.
Solution Approach 2:
The patent implements a feedback mechanism where the control circuit detects the actual operating conditions and adjusts the operating frequency accordingly to maintain stable voltage gain. This closed-loop control eliminates the need for over-engineered high-voltage components by actively managing voltage gain through frequency regulation.
3Loss of energy
If the operating frequency is set to resonant frequency, then input impedance is pure resistance, but the voltage gain deviation impacts conversion efficiency
Solution Approach 1:
The patent applies dynamics by enabling the operating frequency to vary within a specific range (0.85 to 1.15 times the resonant frequency) based on load conditions and coupling factors. This dynamic adjustment maintains both pure resistive input impedance and stable voltage gain, thereby optimizing conversion efficiency across different operating scenarios.
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 configuration ensures a voltage gain that is at most twice that of a full load condition, even with an empty load, improving operational safety and efficiency by stabilizing voltage gain across different operational circumstances.
Implementation Method 1
The transformer includes a primary winding and a secondary winding, and is configured to receive the first AC voltage to generate a second AC voltage
Implementation Method 2
the primary side compensation capacitor and an equivalent primary side leakage inductance of the transformer correspond to a first resonant frequency, the secondary side compensation capacitor and an equivalent secondary side leakage inductance of the transformer correspond to a second resonant frequency
Data Source
AI summary
A power converter includes a primary side compensation capacitor, a transformer and a secondary side compensation capacitor. The primary side compensation capacitor receives a first AC voltage from a first switch circuit. The transformer receives the first AC voltage to generate a second AC voltage. The secondary side compensation capacitor transfers the second AC voltage to a second switch circuit to generate a DC output voltage. The operating frequency of the first switch circuit is set within the 0.8*fa to 1.2*fb, and fb is at most 1.5 times of fa. The primary side compensation capacitor and a primary side leakage inductance of the transformer correspond to a first resonant frequency, the secondary side compensation capacitor and a secondary side leakage inductance of the transformer correspond to a second resonant frequency, fa and fb are the lower one and the higher one of the first and second resonant frequency respectively.