Inductive Vehicle Charging Circuit With AC Impedance Matching
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Solution Overview
Problem
Existing contactless power supply systems for vehicle electrical energy storage units require high frequencies for efficient power transmission, leading to inefficiencies and high switching losses.
Innovation Solution
A secondary sub-circuit with three secondary inductive cells and an inverter/rectifier with parallel switching arms, controlled to achieve impedance matching and phase-shifted operation, reducing switching losses and increasing efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a single secondary inductive cell is used, then device complexity is reduced, but power transmission efficiency decreases
Solution Approach 1:
The patent segments the power transmission system into three independent inductive cell pairs, each operating in parallel. This segmentation improves power transmission efficiency by distributing the power load across multiple cells, reducing the burden on each individual cell and allowing for more efficient operation at lower frequencies.
Solution Approach 2:
The patent combines three parallel inductive cell systems with their respective inverter/rectifier circuits into a unified power transmission system. This merging allows the system to achieve both improved efficiency through multiple cells and manageable complexity through integrated control of all components.
2Loss of energy
If three secondary inductive cells are used with parallel switching arms, then switching losses are reduced, but device complexity increases
Solution Approach 1:
The patent designs the inverter/rectifier circuit with universal switching arms that can operate in complementary patterns to serve multiple functions: impedance matching, power factor correction, and efficient power transfer. This multi-functionality reduces the need for additional dedicated components, thereby managing complexity while achieving reduced switching losses.
Solution Approach 2:
The patent employs periodic complementary switching of the electronic switches in parallel arms, where switches are turned on and off in a coordinated periodic pattern. This periodic action optimizes the operation of each inductive cell pair, minimizing switching losses through synchronized control while maintaining manageable system complexity through repetitive operational patterns.
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 solution enhances efficiency by minimizing switching losses and reducing the complexity and cost of electronic switches, allowing for effective power transfer between 3 kW and 50 kW without excessive energy loss.
Implementation Method 1
three secondary inductive cells, each capable of exchanging electrical energy without contact by inductive coupling with a respective primary inductive cell of the primary sub-circuit
Data Source
Figure 1~2
Figure 3~4
Figure 5~6
AI summary
Secondary sub-circuit (6) for supplying power to an electrical energy storage unit (2), this secondary sub-circuit being capable of exchanging electrical energy without contact by inductive coupling with a primary sub-circuit (4) capable of being connected to a voltage network, and this secondary sub-circuit also being capable of being connected to an electrical energy storage unit, this sub-circuit comprising: - three secondary inductive cells (20), each capable of exchanging electrical energy without contact by inductive coupling with a respective primary inductive cell (10) of the primary sub-circuit, - an inverter/rectifier (23), receiving on its AC input the three-phase voltage corresponding to the three secondary inductive cells (20) and receiving on its DC input a voltage suitable for being connected to the terminals of the electrical energy storage unit (2),the inverter/rectifier (23) comprising a plurality of switching arms (24) mounted in parallel, each switching arm (24) comprising two controllable electronic switches (12) mounted on either side of a midpoint (25), and - a control unit (3) configured to control the controllable electronic switches (12) of the switching arms (24) so as to achieve impedance matching of the impedance on the AC input of this inverter/rectifier (23), independently of the impedance of the electrical energy storage unit (2).