EV Motor Drive Inverter Reuse for On-Board Charging
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Solution Overview
Problem
Conventional electric vehicle systems require multiple components for motor drive and on-board charging, leading to increased cost and volume, as these components do not operate simultaneously, necessitating a solution to reduce the number of components while maintaining functionality.
Innovation Solution
Integration of the motor drive and motor driving inverter into the on-board charger, utilizing relays to reconfigure the topology for power factor correction and current regulation during charging mode, thereby reducing the number of components needed.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If separate components are used for motor drive and on-board charger, then reliability is improved, but device complexity and cost increase
Solution Approach 1:
The patent combines the motor drive inverter and on-board charger into a single integrated power conversion system. The inverter unit uses IGBT switches arranged in a three-phase bridge configuration that can operate in both motor drive mode and charging mode. During charging, the same IGBT switches and DC link capacitor are utilized to convert AC power to DC for battery charging, eliminating the need for a separate charger inverter and reducing overall component count while maintaining system reliability through proven motor drive components
Solution Approach 2:
The inverter unit is designed with multi-functionality to serve dual purposes: motor drive operation and on-board charging. The control unit dynamically reconfigures the IGBT switches and relay connections based on operational mode requirements. The DC link capacitor serves both motor drive voltage stabilization and charger DC output functions. This universal design allows a single component to perform multiple functions, reducing device complexity and cost while maintaining the reliability needed for both applications
2Reliability
If separate components are used for motor drive and on-board charger, then functional reliability is improved, but manufacturing cost increases
Solution Approach 1:
The patent merges the charger inverter and motor drive inverter into a single integrated unit. The same IGBT switches (S1-S6), DC link capacitor (C1), and control unit are used for both motor drive and charging functions. This consolidation eliminates redundant components such as the separate charger inverter, rectifier bridge, and associated control electronics, thereby reducing manufacturing cost while maintaining functional reliability through the use of high-quality motor drive components in a dual-purpose configuration
Solution Approach 2:
The inverter unit is engineered as a universal power conversion system that can operate in both motor drive mode and charging mode. The control unit implements mode-dependent switch configurations: in motor drive mode, IGBTs are controlled for three-phase AC output; in charging mode, the same IGBTs convert AC input to DC for battery charging. This multi-functional design reduces the bill of materials and manufacturing complexity, lowering production costs while ensuring functional reliability through rigorous testing of the integrated system
3Reliability
If separate components are used for motor drive and on-board charger, then operational reliability is improved, but system volume increases
Solution Approach 1:
The patent integrates the on-board charger components into the existing motor drive system. The charger rectifier bridge is combined with the motor drive inverter bridge, sharing the same IGBT switches, DC link capacitor, and control unit. The motor windings themselves are utilized as the charger's output inductors during charging operation. This spatial merging eliminates the need for separate charger components, reducing system volume while maintaining operational reliability through the robust design of the integrated power conversion system
Solution Approach 2:
The power conversion system is designed as a universal unit that performs both motor drive and charging functions using the same physical components. The IGBT switches, DC link capacitor, and control electronics serve dual purposes: driving the motor during vehicle operation and charging the battery during plugging-in events. The motor windings function as both motor coils and charger output inductors. This multi-functional approach maximizes space utilization, reducing system volume while ensuring operational reliability through careful thermal and electrical design of the shared components
Data Source
AI summary
The present disclosure provides a motor drive integrated on-board charger to reduce the quantity of components in an electric system of an electric vehicle. Reduction of components is achieved by utilizing the motor and the motor driving inverter as a part of the on-board charger in the charging mode. By controlling relays, electrical connections of the system may be reconfigured according to its mode of operation. In one aspect, the motor and the motor driving inverter play the roles of a boost PFC, a current regulator, or both.