Secondary-Side Power Receiving Circuit for Contactless Power Feed
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Solution Overview
Problem
Existing contactless power feed equipment often overloads when multiple devices start up simultaneously, leading to power shutdowns due to excessive load on the primary-side power supply device.
Innovation Solution
A secondary-side power receiving circuit that includes a pickup coil, resonant capacitor, full-wave rectifying circuit, switch, and controller with pulse generating and pulse width control circuits to manage power distribution, ensuring each device receives only its share of power at startup, thereby preventing overload.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the output voltage is set at 0 V or close to 0 V in initial condition for starting power supply, then the switching control can monitor the output voltage to be set at the reference voltage, but the switch is continuously opened requiring 100% load condition which causes overload and power supply interruption
Solution Approach 1:
The patent applies periodic action by using pulse width modulation to periodically switch the switch between on and off states. The pulse width control circuit generates periodic control signals that regulate the duty cycle of the switch, transforming the continuous full-load condition into a periodic on-off operation. This allows the power supply to deliver controlled average power while maintaining stability, preventing overload by ensuring the load does not continuously demand 100% power capacity.
2Productivity
If a large number of devices are operated simultaneously at startup, then power distribution efficiency improves, but the power supply device becomes overloaded exceeding rated power and activates protective function interrupting power supply
Solution Approach 1:
The patent implements feedback control through the pulse width control circuit that continuously monitors the output voltage and adjusts the pulse width of control signals accordingly. The control circuit receives feedback about the actual power consumption and load conditions, dynamically adjusting the duty cycle to maintain output voltage within reference ranges. This feedback mechanism enables the system to handle multiple devices simultaneously by automatically regulating power distribution to prevent total power demand from exceeding the power supply device's rated capacity.
3Measurement precision
If the switch is continuously opened to maintain output voltage control, then voltage regulation is achieved, but the output capacitor is continuously charged requiring full-load condition which reduces system adaptability
Solution Approach 1:
The patent applies dynamics by transitioning from static continuous switch opening to dynamic periodic switching controlled by pulse width modulation. The switch operates in a dynamic on-off cycle with variable duty cycle, allowing the system to adapt to different load conditions while maintaining voltage control precision. The pulse width control circuit dynamically adjusts the switching parameters based on real-time feedback, enabling the system to maintain precise voltage regulation across varying load demands without requiring continuous full-load operation.
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
Enables continuous power supply to a large number of devices without overloading the primary-side power supply, as the power distribution is managed to maintain a stable output voltage and prevent shutdowns.
Implementation Method 1
a pickup coil opposed to a primary-side induction line that receives a high-frequency current from a power supply device, the pickup coil receiving an induced electromotive force from the primary-side induction line
Implementation Method 2
a resonant capacitor connected in parallel with the pickup coil, the resonant capacitor forming a resonant circuit that resonates at the frequency of the high-frequency current with the pickup coil
Data Source
AI summary
A PWM module is provided to output a driving pulse to a switching device in synchronization with a synchronizing pulse having a frequency twice the frequency of the high-frequency current of a primary-side induction line. The PWM module performs output voltage feedback control such that the output voltage of an output capacitor is set at a reference voltage. The module outputs, to the switching device, the driving pulse having a half width of the pulse width of a driving pulse that can be outputted, at the start of power supply to the primary-side induction line. Moreover, the module forcibly performs the output voltage feedback control if an output voltage of the output capacitor does not increase to the reference voltage within a reference time.