Wireless Power Control Circuit Pulse Density Modulation
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Solution Overview
Problem
Existing wireless power supply systems face challenges in ensuring safety and reliability while enhancing efficiency, as factors like coil positioning, coupling, power consumption, and input voltage can lead to abnormal conditions, making it difficult to protect the power transmission and reception circuits effectively.
Innovation Solution
A wireless power supply system employing a power transmission device with a pulse-density modulation control method, using a control circuit to adjust oscillation pulse density based on demodulation, output detection, and temperature feedback to manage power flow efficiently and prevent overheating or excessive power supply, along with a power reception device that converts high-frequency power into direct-current power and detects load states to generate transmission signals for feedback control.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the power transmission device operates at high pulse density to improve power supply efficiency, then the power transmission efficiency is improved, but the temperature of the heating portion increases causing overheating and potential damage
Solution Approach 1:
The patent applies periodic action by using pulse-density modulation control that operates in cycles: the control circuit periodically measures temperature at predetermined intervals and adjusts pulse density accordingly. The system alternates between high pulse density (for efficiency) and low pulse density (for cooling) based on temperature feedback, creating a periodic on-off pattern that prevents continuous overheating while maintaining average power supply efficiency
Solution Approach 2:
The patent implements feedback control through a temperature measurement unit that continuously monitors the heating portion temperature and feeds this information back to the control circuit. The control circuit uses this feedback to dynamically adjust the pulse density of the power transmission circuit, reducing pulse density when temperature exceeds thresholds and restoring it when temperature decreases, thereby maintaining both efficiency and safety
2Temperature
If the power transmission device restricts pulse density to prevent overheating, then the temperature is controlled, but the power supply efficiency decreases
Solution Approach 1:
The patent applies dynamics by making the pulse density adjustable and time-variable rather than fixed. The control circuit dynamically changes pulse density based on real-time temperature conditions: operating at high pulse density when temperature is acceptable (maintaining efficiency) and reducing pulse density when temperature rises (preventing overheating). This dynamic adjustment resolves the contradiction by allowing the system to adapt between the two opposing requirements
Solution Approach 2:
The patent implements beforehand cushioning by setting predetermined temperature thresholds before dangerous overheating occurs. When the temperature reaches these pre-set thresholds, the control circuit proactively reduces pulse density to prevent further temperature rise and potential damage. This preventive approach allows the system to maintain high efficiency during normal operation while having safety mechanisms ready to activate before critical failure occurs
3Reliability
If the system uses complex control mechanisms to protect against abnormal conditions, then the safety and reliability are improved, but the device complexity increases
Solution Approach 1:
The patent applies self-service by enabling the power transmission device to automatically monitor its own temperature and self-regulate its pulse density without external intervention. The temperature measurement unit and control circuit work autonomously to detect abnormal conditions and adjust operation accordingly, eliminating the need for complex external monitoring systems or manual safety mechanisms while maintaining high reliability
Solution Approach 2:
The patent implements universality by designing the control circuit to perform multiple functions: it controls power transmission, measures temperature, determines abnormal conditions, and adjusts pulse density all through a single integrated control mechanism. This multi-functional approach consolidates what could be separate complex subsystems into one unified control unit, improving reliability while minimizing the increase in device complexity
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
The system ensures high efficiency and safety by restricting pulse density in overheating or excessive power states, stabilizing power output, and maintaining electromagnetic resonance for stable signal transmission, thereby enhancing the overall reliability and efficiency of wireless power supply.
Implementation Method 1
a wireless power supply system of wirelessly supplying power from a power transmission device to a power reception device by magnetic-field coupling
Implementation Method 2
a power reception circuit configured to convert high-frequency power received by the power reception coil into direct-current power
Implementation Method 3
a wireless power supply system in which a power transmission coil and a power reception coil are also used in transmitting signals
Data Source
AI summary
A wireless power supply system includes a power transmission device and a power reception device. A control circuit in the power transmission device causes a power transmission circuit to operate, by a pulse-density modulation control method of controlling density of oscillation pulses for a predetermined period of time, in relationship De1>De2>De3, where De1 indicates the pulse density determined on the basis of a result of demodulation of a transmission signal from the power reception device, De2 indicates the pulse density in a state where a detected output value from the power transmission circuit reaches a predetermined value, and De3 indicates the pulse density in a state where a detected temperature values of a switch element reaches a predetermined value.