EV Drive Power Module Reuse for Compact Bidirectional Conversion
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Solution Overview
Problem
Existing electric vehicle drive systems face challenges in reducing volume and improving energy efficiency due to the presence of high-power inductors and direct current conversion modules, which hinder space savings and endurance mileage.
Innovation Solution
The system reuses components from the generator rectifier circuit and motor drive circuit, including bridge arms and bus capacitors, to form parallel connections, allowing for efficient energy conversion and storage, and includes a power module to manage power flow between the battery, generator, and motor.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a bidirectional direct current conversion module is added to support charging/discharging of power battery, then charging/discharging function is improved, but system volume increases and energy efficiency deteriorates
Solution Approach 1:
The patent makes the bridge arm circuit perform multiple functions: it serves as both the charging/discharging switch circuit and the motor control circuit. By configuring the bridge arm midpoint to connect to the power battery and the two ends to connect to the bus capacitor, the same circuit structure enables bidirectional power flow for battery charging/discharging and three-phase current output for motor drive, eliminating the need for separate conversion modules
Solution Approach 2:
The patent merges the charging/discharging direct current conversion function with the motor drive circuit by using the same bridge arm circuit and bus capacitor for both purposes. The controller integrates control of both functions, combining what would traditionally be separate modules into a unified system that reduces overall volume while maintaining full functionality
2Adaptability or versatility
If a bidirectional direct current conversion module is added to support charging/discharging of power battery, then charging/discharging function is improved, but energy efficiency deteriorates
Solution Approach 1:
The bridge arm circuit serves dual purposes as both the charging/discharging switch and motor control circuit, eliminating energy losses associated with separate conversion modules. The same switching devices and circuit topology handle both battery power management and motor drive operations, reducing cumulative energy losses
Solution Approach 2:
The controller dynamically changes operating parameters of the bridge arm circuit to optimize performance for different modes (charging, discharging, motor drive). By adjusting switching frequencies, duty cycles, and control strategies based on real-time operating conditions, the system maintains high energy efficiency across all functions without requiring separate optimized modules
3Power
If high-power inductor and direct current conversion module are used, then power conversion capability is improved, but system volume increases
Solution Approach 1:
The bridge arm circuit universally handles both high-power charging/discharging conversion and motor drive functions without requiring separate high-power inductors or conversion modules. The circuit achieves power conversion capability through its switching topology and control strategy rather than relying on large passive components, significantly reducing volume
Solution Approach 2:
The patent extracts and eliminates the high-power inductor and separate direct current conversion module from the system by integrating their functions into the bridge arm circuit. The bridge arm alone, controlled by the controller, provides the necessary power conversion capability without bulky passive components, reducing system volume while maintaining power handling capacity
Data Source
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AI summary
This application provides an electric vehicle drive system, a controller, and an electric vehicle. The electric vehicle drive system includes at least one of a generator rectifier circuit and a motor drive circuit, and a power module. A bridge arm midpoint of a first bridge arm in the power module is configured to connect to a power battery, and two ends of the first bridge arm are respectively configured to connect to two ends of a bus capacitor. Two ends of three second bridge arms connected in parallel in the generator rectifier circuit are respectively configured to connect to the two ends of the bus capacitor, and bridge arm midpoints of all the second bridge arms are separately configured to connect to a generator. Two ends of three third bridge arms connected in parallel in the motor drive circuit are respectively configured to connect to the two ends of the bus capacitor, and bridge arm midpoints of all the third bridge arms are separately configured to connect to a drive motor. According to this application, the power module can reuse a component in the generator rectifier circuit or the motor drive circuit. This reduces a volume of the electric vehicle drive system, improves energy efficiency, and further improves applicability.