Power Receiver PWM Drive for Balanced Multi-Device Charging
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Solution Overview
Problem
Conventional contactless power receiving apparatuses face inefficiencies in electric power reception due to varying positions and orientations, leading to imbalanced power supply when multiple receivers are involved, making it difficult to distribute power evenly.
Innovation Solution
A power receiver system with a secondary-side resonant coil, a capacitor, a rectifier circuit, a smoothing circuit, and a switch driven by a PWM pattern to optimize power reception efficiency, adjusting duty cycles based on individual load efficiencies and mutual inductances to ensure balanced power distribution among multiple receivers.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If electric power is transmitted without considering the efficiency of electric power reception, then the power transmission system is simple to operate, but the power supply becomes imbalanced when multiple receivers are present
Solution Approach 1:
The patent implements a feedback mechanism where the power transmitter receives efficiency information from each power receiver and uses this feedback to dynamically adjust transmission parameters. The controller calculates individual efficiency values based on received power and transmitted power, then uses this feedback to balance power distribution across multiple receivers, resolving the contradiction between operational simplicity and power supply reliability.
Solution Approach 2:
The system dynamically adjusts transmission parameters based on real-time efficiency measurements. The power transmitter modifies transmission power levels for each receiver according to their individual efficiency values and power demands, transforming a static transmission system into a dynamic one that adapts to varying receiver positions, orientations, and power requirements, thereby achieving balanced power distribution.
2Reliability
If the efficiency of electric power reception is optimized for each receiver, then the power supply balance improves, but the system complexity increases
Solution Approach 1:
The patent employs a universal communication protocol and control architecture that can handle multiple receivers with different efficiency characteristics through a single integrated system. The power transmitter uses a unified control mechanism that simultaneously manages multiple receivers, calculating individual efficiency values and adjusting transmission parameters for each receiver within the same system framework, thereby achieving balanced power distribution without proportionally increasing system complexity.
Solution Approach 2:
The system optimizes power reception by dynamically changing transmission parameters such as power level and frequency based on measured efficiency values. The controller adjusts these parameters for each receiver individually, allowing the system to adapt to varying receiver conditions (position, orientation, load) without requiring complex hardware modifications, thus achieving reliability improvement with controlled complexity increase.
3Productivity
If PWM drive patterns are adjusted based on efficiency and load ratings, then power distribution efficiency improves, but the control complexity increases
Solution Approach 1:
The control system uses feedback from efficiency measurements and load rating information to dynamically adjust PWM drive patterns. The controller receives efficiency data from each receiver, combines it with known load ratings, and automatically calculates optimal PWM duty cycles and frequencies, thereby achieving efficient power distribution without requiring manual intervention or overly complex control logic.
Solution Approach 2:
The system enables receivers to self-report their efficiency characteristics and load requirements, allowing the power transmitter to automatically optimize power distribution. Each receiver provides necessary information about its operational state, and the controller uses this self-reported data along with efficiency measurements to autonomously adjust transmission parameters, reducing the need for external control complexity while improving power distribution efficiency.
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 improves power supply balance by dynamically adjusting the PWM drive patterns to match the efficiency of each receiver, ensuring that power is distributed evenly and efficiently among multiple devices, even when their orientations and positions relative to the transmitter vary.
Implementation Method 1
a first secondary-side resonant coil, including a resonant coil part, a first terminal and a second terminal, that receives electric power from a primary-side resonant coil through magnetic field resonance generated between the primary-side resonant coil and the first secondary-side resonant coil
Implementation Method 2
an excitation element adapted to receive supply of the alternating-current power by electromagnetic induction from the resonance element; a rectification circuit adapted to generate direct-current power from the alternating-current power from the excitation element
Data Source
AI summary
A power receiver includes: a first secondary-side resonant coil that receives electric power from a primary-side resonant coil through magnetic field resonance; a capacitor; a smoothing circuit; a pair of output terminals; a switch coupled in parallel to the capacitor or in series between a rectifier circuit and either a first terminal or a second terminal; and a drive controller that drives the switch through a first PWM drive pattern determined by a first duty cycle and by a first frequency that is less than or equal to a frequency of the magnetic field resonance. The first duty cycle is set based on a first efficiency of power reception of the first secondary-side resonant coil, a first rated output of a first load, a second efficiency of power reception of a second secondary-side resonant coil of another power receiver, and a second rated output of a second load.