Power Conversion Apparatus for Vibration-Free EV Charging
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Solution Overview
Problem
Existing power conversion systems for electric vehicles face challenges in reducing vibration during charging, as the motor coil is used as an AC reactor, leading to torque being applied to the motor, which can cause vibration.
Innovation Solution
A power conversion apparatus that supplies a polyphase AC motor with driving voltages from both AC and DC power supplies, using a conversion unit with switching devices and a power controller to generate pulse-width-modulation pulses, allowing for selective use of voltages from AC and DC power supplies to operate the motor without unnecessary torque and vibration.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If the motor coil is used as an AC reactor during charging, then the charging function is integrated into the inverter, but torque is applied to the motor causing vibration
Solution Approach 1:
The patent extracts the motor coil from its dual function as both motor actuator and AC reactor. During charging operation, the motor coil connections are disconnected from the inverter output, separating the motor function from the reactor function. This allows the inverter to charge the battery without applying torque to the motor, eliminating vibration while maintaining system integration benefits
Solution Approach 2:
The patent implements dynamic switching of the motor coil connections based on operational mode. A control circuit dynamically connects or disconnects the motor coil from the inverter output depending on whether the system is in motor driving mode or battery charging mode. This dynamic reconfiguration allows the same hardware to serve different functions without causing harmful effects
2Adaptability or versatility
If a double-throw switch is provided with motor coil as AC reactor, then both motor driving and battery charging control are performed by the inverter, but the system requires complex switching mechanisms
Solution Approach 1:
The patent makes the inverter universal by enabling it to perform both motor driving control and battery charging control through software control logic rather than hardware duplication. The same inverter circuitry serves dual purposes by dynamically reconfiguring its connections, eliminating the need for separate charging circuits and reducing overall system complexity despite the multi-functional requirement
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 the size and weight of the power conversion system while preventing unnecessary motor torque and vibration, enabling efficient and vibration-free operation by selectively using AC and DC power supply voltages.
Implementation Method 1
generate pulse-width-modulation pulses based on the first modulation factor command value and the second modulation factor command value
Data Source
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AI summary
An apparatus and method for supplying a polyphase (AC) alternating current motor (15) with driving voltages. A conversion unit (12) is coupled to phases of the polyphase AC motor and includes a plurality of switching devices and includes, in at least one phase, a first switching device (25b,26b,27b) between a bus (24) of an AC power supply and an output terminal, a second switching device (21b,22b,23b) between a bus (16) of a direct current (DC) power supply and the output terminal, and a third switching device (18a,18b,19a,19b,20a,20b) between a common bus (17) for the AC power supply and the DC power supply and the output terminal. Driving voltages for the polyphase AC motor are generated by selecting a voltage from among voltages having potential values corresponding to the AC power supply and the DC power supply, and the selected voltage is used to operate a switch of the plurality of switching devices.