Non-Contact Power Transfer Circuit for Constant Receiver Voltage
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Solution Overview
Problem
Existing non-contact feeding devices face challenges in maintaining a constant output voltage on the power receiving side due to fluctuations in the input voltage to the power supply circuit, which can lead to power loss and potential breakdowns in load circuits designed for constant voltage operations.
Innovation Solution
A non-contact feeding device is designed with a power transmission device that includes a transmission coil, a power supply circuit with a voltage detection circuit and a control circuit to adjust the degree of boosting or stepping down of the input voltage, allowing the inverter to switch between full-bridge and half-bridge operations based on input voltage levels, ensuring a constant output voltage on the receiving side.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If the voltage input to the power factor improvement circuit fluctuates excessively high, then the voltage taken out from the receiving coil becomes higher than the target value, but this causes breakdown in load circuits designed for constant voltage operation
Solution Approach 1:
The control circuit continuously monitors the input voltage to the power factor improvement circuit and adjusts the boosting ratio in real-time based on the measured voltage fluctuations. This feedback mechanism ensures that even when input voltage varies, the output voltage to the transmission coil is regulated, preventing excessive voltage from reaching the load circuit through the resonance coupling.
Solution Approach 2:
The system dynamically changes the boosting ratio parameter of the power factor improvement circuit based on the detected input voltage conditions. When input voltage is high, the boosting ratio is reduced; when input voltage is low, the boosting ratio is increased. This parameter adjustment maintains stable output voltage despite input fluctuations.
2Power
If a DC-DC converter is provided to lower the voltage of supplied power, then the voltage can be reduced to appropriate levels, but power loss is generated which is undesirable
Solution Approach 1:
The power factor improvement circuit performs voltage regulation and boosting before the power reaches the resonance circuit and transmission coil. By pre-adjusting the voltage to the appropriate level at the transmission side, the system eliminates the need for additional voltage conversion stages at the receiving side, thereby avoiding the power losses that would occur in DC-DC converters.
3Power
If the voltage output from the power factor improvement circuit is higher than input voltage due to boosting function, then voltage can be increased for resonance operation, but when input voltage fluctuates excessively high, the output voltage exceeds target value
Solution Approach 1:
The power factor improvement circuit operates dynamically, continuously adjusting its boosting ratio based on real-time input voltage conditions. Rather than maintaining a fixed boosting ratio, the circuit adapts its transformation ratio to maintain stable output voltage despite variations in input voltage, enabling both voltage boosting capability and output stability.
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 effectively maintains a constant output voltage on the power receiving side even with fluctuating input voltages, preventing power loss and ensuring stable operation of load circuits.
Implementation Method 1
a coil (hereinafter referred to as a transmission coil) operating as a part of a transformer is provided on a primary side (power transmission side) and a coil (hereinafter referred to as a receiving coil) operating as another part of the transformer is provided on a secondary side (power receiving side). A device on the power transmission side supplies AC power to the transmission coil to transmit the power from the transmission coil to the receiving coil.
Implementation Method 2
in the case that the power is received through a resonance circuit in which the receiving coil and a capacitor resonate in parallel on the power receiving side, voltage of the transmitted power is also required to increase in order to increase the Q value
Data Source
AI summary
A power transmission device of the non-contact feeding device includes the transmission coil that supplies power to a power receiving device, a power supply circuit that supplies AC power obtained by boosting or stepping down the input voltage to the transmission coil, a voltage detection circuit that measures the voltage input to the power supply circuit, and a control circuit that controls a degree of boosting or step-down with respect to the input voltage by the power supply circuit according to the input voltage measured. The power receiving device includes a resonance circuit including a receiving coil that receives the power from the power transmission device and a resonance capacitor that resonates with the receiving coil according to the power from the power transmission device and a rectifier circuit that rectifies the power output from the resonance circuit.