SEM Drive Bi-Directional Charging Without Onboard Charger
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Solution Overview
Problem
Existing electrical systems for charging batteries in hybrid and electric vehicles are inefficient and require bulky Onboard Charging Modules (OBCM) for AC charging, limiting scalability and increasing mass and cost.
Innovation Solution
Implementing a bi-directional power flow system using a separately excited motor (SEM) drive with a traction inverter module (TIM) and rotor-excitation power transfer circuit (PTC), coupled with a multilevel power factor correction (PFC) converter for galvanically isolated high-voltage charging, eliminating the need for OBCM and enhancing efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a conventional onboard charging module (OBCM) is used for AC charging, then the vehicle can be charged from AC power sources, but the system increases mass, cost, and packaging space requirements
Solution Approach 1:
The patent applies multi-functionality by enabling the SEM drive system to perform both motor propulsion and battery charging functions. The inverter and power transfer circuit are designed to operate in bidirectional modes, serving as motor drive during propulsion and as charging equipment when connected to AC power sources, thereby eliminating the need for separate OBCM hardware
Solution Approach 2:
The patent combines the OBCM functionality with the existing SEM drive system components. The inverter and power transfer circuit that originally served only motor control are merged to also perform AC-DC conversion and battery charging functions, consolidating multiple systems into a unified architecture that reduces overall mass and component count
2Adaptability or versatility
If a conventional onboard charging module (OBCM) is used for AC charging, then the vehicle can be charged from AC power sources, but the system increases packaging space requirements
Solution Approach 1:
The SEM drive system components are designed with multi-functionality to perform both motor propulsion and battery charging operations. The inverter and power transfer circuit can switch between motor drive mode and charging mode, eliminating the need for dedicated OBCM hardware and thereby reducing packaging space requirements
Solution Approach 2:
The patent merges the charging function into the existing motor drive system. By combining the OBCM functionality with the inverter and power transfer circuit, the system consolidates multiple functions into shared hardware, significantly reducing the volume required for charging equipment
3Adaptability or versatility
If a conventional onboard charging module (OBCM) is used for AC charging, then the vehicle can be charged from AC power sources, but the system increases cost
Solution Approach 1:
The patent implements multi-functionality in the SEM drive system, allowing the same hardware components (inverter, power transfer circuit) to serve dual purposes: motor propulsion and battery charging. This eliminates the need for separate OBCM components, reducing overall system cost through component consolidation and eliminating redundant hardware
Solution Approach 2:
The charging system is merged with the motor drive system, combining previously separate functions into a unified architecture. This consolidation reduces manufacturing costs by eliminating duplicate components, reducing assembly complexity, and leveraging existing semiconductor devices and control infrastructure
4Weight of moving object
If a separately excited motor (SEM) drive system is implemented for bidirectional charging, then mass and packaging requirements are reduced, but the system complexity increases
Solution Approach 1:
The patent applies dynamics by implementing bidirectional power flow capability in the SEM drive system. The inverter and power transfer circuit can dynamically switch between motor drive mode and charging mode, with control logic that adapts the system operation based on whether the vehicle is propelling or being charged, enabling flexible functionality without additional hardware
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 SEM drive system enables efficient, cost-effective, and space-saving AC charging with reduced mass and packaging requirements, allowing bi-directional power flow between the vehicle's battery and the power grid.
Implementation Method 1
a separately excited motor (SEM) drive with a traction inverter module (TIM) and rotor-excitation power transfer circuit (PTC)
Implementation Method 2
multilevel power factor correction (PFC) converter for galvanically isolated high-voltage charging
Data Source
AI summary
Presented are separately excited motor (SEM) drive systems, methods for making/using such systems, and vehicles equipped with such systems. A motor drive system includes a rechargeable battery unit and a multilevel power factor correction (PFC) device interposed between and electrically connecting the battery unit and an electric power source. The battery unit and PFC device are electrically connected via a traction inverter module (TIM) device and a multilevel power transfer circuit (PTC) device. The TIM contains multiple pairs of TIM switches, and the PTC device contains multiple PTC switches. An SEM unit contains a rotor assembly, which includes a rotor core bearing a rotor winding, and a stator assembly, which includes a stator core bearing multiple stator windings electromagnetically paired with the rotor winding. Each stator winding is electrically connected to a respective pair of TIM switches, whereas the rotor winding is electrically connected to the PTC switches.