Inductive Vehicle Battery Supply Circuit With Low-Frequency Impedance Control
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Solution Overview
Problem
Existing contactless power supply systems for vehicle electrical energy storage units operate at high frequencies and short distances, posing health and environmental risks and requiring complex cooling systems due to high losses and heating in switching arms.
Innovation Solution
A power supply circuit with a primary and secondary sub-circuit configured for inductive coupling, using an inverter/rectifier with switching arms and a control unit to control switching frequencies and duty cycles, optimizing impedance adaptation and minimizing current flow to reduce losses and heating.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If high frequency operation is used to transmit several kW power level, then power transmission efficiency is improved, but health and environmental safety deteriorates
Solution Approach 1:
The patent changes the operating frequency parameter from high frequency (85 kHz or more) to low frequency (below 10 kHz, preferably 400 Hz or 50 Hz). This parameter change allows maintaining satisfactory power transmission capability while eliminating the harmful effects associated with high frequency operation, thus resolving the contradiction between productivity and safety.
2Power
If high frequency operation is used for contactless power transmission, then power transmission capability is improved, but device complexity increases due to cooling systems
Solution Approach 1:
By changing the operating frequency from high to low, the patent reduces power losses in the switching arms (as losses are frequency-dependent). This reduction in losses consequently reduces heating, which eliminates or simplifies the need for complex cooling systems while maintaining satisfactory power transmission capability.
3Productivity
If high frequency operation is used, then power transmission efficiency is improved, but loss of energy increases due to heating
Solution Approach 1:
The patent applies parameter change by operating at low frequency (below 10 kHz) instead of high frequency. Since power losses in inductive coupling systems are proportional to frequency, this parameter change directly reduces energy losses due to heating in the switching arms and magnetic components, thereby resolving the contradiction between productivity and energy loss.
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 reduces heating in switching arms, eliminates the need for cooling systems, improves compactness and cost, and enhances the efficiency of power transmission to electrical energy storage units.
Implementation Method 1
the primary sub-circuit and the secondary sub-circuit being configured so as to exchange electrical energy without contact by inductive coupling
Implementation Method 2
the secondary inductive cell implementing a secondary capacitor and a secondary inductor
Implementation Method 3
the secondary inductive cell implementing a secondary capacitor and a secondary inductor
Data Source
Figure 1
AI summary
Electrical power supply circuit (1) for an electrical energy storage unit (2), this electrical power supply circuit comprising: - a primary sub-circuit (4), capable of being connected to a voltage network (5), and - a secondary sub-circuit (6), capable of being connected to an electrical energy storage unit (2), the primary sub-circuit (4) and the secondary sub-circuit (6) being configured so as to exchange electrical energy without contact by inductive coupling, the secondary sub-circuit (6) comprising: - a secondary inductive cell (20) for the contactless exchange by inductive coupling of electrical energy with the primary sub-circuit (4), - an inverter/rectifier (23) capable of performing an impedance adaptation of the impedance on the alternating input of this inverter/rectifier (23), independently of the impedance of the electrical energy storage unit (2), this inverter/rectifier (23) comprising at least two switching arms,each switching arm comprising two electronic switches arranged on either side of a midpoint, and - a control unit (3) configured to control one of these two arms so that it switches at the frequency of the electrical energy exchanged without contact by inductive coupling and with a duty cycle of 50%, and to control the other of these two arms so that it switches at a frequency higher than that of said electrical energy and with a duty cycle modulated according to the alternating current flowing in the secondary inductive cell (20) and the voltage on the alternating input of this inverter/rectifier (23).,