Inductive Vehicle Power Supply Circuit With Secondary Impedance Matching
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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, costly, and heavy primary circuits to achieve impedance matching.
Innovation Solution
A secondary sub-circuit with a voltage converter that performs impedance adaptation independently of the energy storage unit's impedance, converting alternating to direct voltage, allowing low-frequency energy transfer without increasing primary circuit complexity or weight.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If high-frequency resonant coupling is used to transmit several kW of power, then power transmission capability 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 5 kHz, preferably below 1 kHz). This parameter change allows power transmission of several kW while avoiding the harmful effects associated with high-frequency electromagnetic fields, thus resolving the contradiction between power transmission capability and health/environmental safety
Solution Approach 2:
The patent employs periodic switching of electronic switches (MOSFETs or IGBTs) at low frequency to generate alternating voltage across the secondary inductive cell. This periodic action at low frequency enables power transmission while maintaining safety, as the low-frequency electromagnetic fields do not pose the same health risks as high-frequency fields
2Adaptability or versatility
If the number of turns of the primary sub-circuit is increased to achieve impedance matching for medium or low voltage storage units, then impedance matching capability is improved, but weight and cost deteriorates
Solution Approach 1:
The patent changes the approach to impedance matching by introducing a voltage converter with electronic switching at the secondary side. Instead of changing the physical parameter of the primary circuit (number of turns), the patent uses electronic parameter control (switching duty cycle and frequency) to achieve impedance matching. This allows adaptation to different storage unit voltages (12V, 48V, 60V, up to 200V or 300V) without increasing primary circuit weight
Solution Approach 2:
The patent introduces a voltage converter as an intermediary device between the secondary inductive cell and the electrical energy storage unit. This intermediary performs impedance adaptation and voltage conversion, eliminating the need to modify the primary sub-circuit. The voltage converter includes switching arms with electronic switches that enable flexible impedance matching for various storage unit specifications
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 efficient, low-frequency energy transfer to medium or low-voltage storage units, reducing health risks and costs by eliminating the need for additional turns and weight in the primary circuit.
Implementation Method 1
a secondary inductive cell capable of exchanging electrical energy with the primary sub-circuit without contact by inductive coupling
Implementation Method 2
a voltage converter capable of performing an impedance adaptation of the impedance on the alternating input of this voltage converter, independently of the impedance of the electrical energy storage unit
Implementation Method 3
this voltage converter converting the alternating voltage at the terminals of the secondary inductive cell into at least one intermediate voltage, and this voltage converter converting the intermediate voltage into a direct output voltage
Data Source
Figure 1~2
AI summary
Secondary sub-circuit (6) for an electrical power supply circuit (1) of an electrical energy storage unit (2), the secondary sub-circuit (6) being capable of contactless exchange by inductive coupling of electrical energy with a primary sub-circuit (4) capable of being connected to a voltage network (5), the secondary sub-circuit (6) being capable of being connected to an electrical energy storage unit (2), the secondary sub-circuit (6) comprising: - a secondary inductive cell (20) capable of contactless exchange by inductive coupling of electrical energy with the primary sub-circuit (4), - a voltage converter (30) capable of performing an impedance adaptation of the impedance on the alternating input of this voltage converter (23), independently of the impedance of the electrical energy storage unit (2),this voltage converter (30) converting the alternating voltage at the terminals of the secondary inductive cell (20) into at least one intermediate voltage (Vint; Vint1, Vint2), and this voltage converter (30) converting the intermediate voltage into a direct output voltage (Vbatt) capable of being connected to the terminals of the electrical energy storage unit (2), the value of this direct output voltage (Vbatt) being lower than that of the intermediate voltage (Vint; Vint1, Vint2).,