Non-Contact Power Supply Rectangular Wave Control
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Solution Overview
Problem
Non-contact power supply systems experience reduced efficiency in power transmission when delivering power lower than the predetermined rated power, due to limitations in impedance adjustment using DC/DC converters, which lead to increased losses and difficulty in suppressing transmission efficiency reduction.
Innovation Solution
A non-contact power supply system that includes a first converter for AC power conversion, a magnetically coupled second coil for power transmission, a second converter for DC power delivery to a load, and a control unit that alternates between outputting rectangular wave voltage and constant reference voltage based on the load's required power, allowing for efficient power adjustment.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If the adjustment amount of impedance increases, then power transmission efficiency can be maintained, but loss in the DC/DC converter and loss in a power-receiving-side rectifier increase
Solution Approach 1:
The periodic alternation between rectangular wave voltage output and reference voltage output provides a natural mechanism for impedance adjustment. By varying the duty cycle of the rectangular wave periods within the periodic cycle, the system achieves wide impedance adjustment range while maintaining transmission efficiency, avoiding the need for complex additional adjustment mechanisms
2Power
If power lower than predetermined rated power is transmitted, then power conversion is performed, but efficiency of power transmission between the coils is reduced
Solution Approach 1:
The system changes the operating parameter by alternately outputting rectangular wave voltage and reference voltage. This parameter change allows the first converter to maintain optimal operating conditions even when transmitting power lower than rated power, preventing the efficiency reduction that would normally occur at partial load conditions
Solution Approach 2:
By using periodic rectangular wave voltage output combined with reference voltage periods, the system maintains magnetic coupling efficiency across a wide range of power levels. The periodic rectangular wave excitation ensures sufficient magnetic field strength for efficient coupling even at reduced power transmission levels
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 the supply of desired power to a load while minimizing the reduction in power transmission efficiency, maintaining high efficiency even when delivering power lower than the rated power by optimizing the ratio of rectangular wave and reference voltage periods.
Implementation Method 1
a second coil magnetically coupled with the first coil so that the AC power is transmitted from the first coil to the second coil
Data Source
AI summary
A first converter performs power conversion and outputs AC power. The AC power outputted from the first converter is supplied to a first coil. The first coil is magnetically coupled with a second coil, and the AC power is transmitted from the first coil to the second coil. A second converter is connected to the second coil, and converts the AC power transmitted to the second coil to DC power and supplies the DC power to a load. A first control unit controls the first converter so as to alternately switch between a first state of outputting rectangular wave voltage which cyclically changes and a second state of outputting constant reference voltage, on the basis of required power of the load.