Parallel Low-Voltage Motor Drive Modules for Lower Switching Loss
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Solution Overview
Problem
Conventional electric motor systems for electric vehicles face inefficiencies and safety concerns due to high voltage requirements, leading to increased losses, insulation challenges, and EMI issues, as well as complexity in power electronics and battery management.
Innovation Solution
The electric motor system employs a parallel low-voltage configuration with multiple power electronics drive modules and direct current power supply lines, reducing power handling and losses by using low-voltage power switches, and integrating power electronics directly with the motor unit for efficient and redundant operation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If high voltage is used to power series-connected motor coils, then motor top speed and torque capability are improved, but power electronics losses and insulation requirements increase
Solution Approach 1:
The patent divides the motor system into multiple independent motor units, each with its own power electronics module. Instead of using a single high-voltage system, multiple low-voltage modules operate in parallel. Each module handles a subset of motor coils, segmenting the overall power delivery function. This segmentation allows the use of lower voltage switches in each module, reducing conduction and switching losses while maintaining the total power output capability through parallel operation of multiple modules.
2Power
If high voltage is used to power series-connected motor coils, then motor top speed and torque capability are improved, but insulation requirements and EMI issues increase
Solution Approach 1:
By segmenting the motor system into multiple low-voltage modules, each module operates at lower voltage levels that require less stringent insulation. The parallel architecture isolates EMI sources within individual modules, making electromagnetic interference more contained and manageable compared to a single high-voltage system where EMI propagates throughout the entire system.
3Speed
If high voltage switches are used to overcome series coil back EMF, then motor speed capability is improved, but device complexity and cost increase
Solution Approach 1:
The patent segments the power electronics function across multiple independent modules, each using simpler low-voltage switches. Rather than requiring one complex high-voltage switch per coil, each module uses multiple low-voltage switches to control its subset of coils. This segmentation trades the complexity of high-voltage switching for the simplicity of parallel low-voltage module operation.
4Speed
If high voltage is used to reach desired motor top speed, then speed capability is improved, but safety concerns during accidents increase
Solution Approach 1:
The motor system is divided into multiple independent low-voltage modules rather than a single high-voltage system. In the event of an accident or failure, the lower voltage levels in each module inherently present reduced safety risks. The modular architecture also allows for isolation of faulty modules, containing potential hazards within individual low-voltage units rather than exposing the entire system at high voltage.
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
This configuration achieves significant reductions in losses, improved efficiency, and enhanced safety by minimizing high current transmission and utilizing low-voltage switches, resulting in a more reliable and efficient electric motor system.
Implementation Method 1
a power converter operative to convert direct current into a periodic current (e.g. pulsed direct current or an alternating current) for powering the activatable motor elements
Implementation Method 2
each activatable motor element being operative when activated by application of an electric current thereto for creating relative movement between the first and second parts
Data Source
AI summary
An electric motor system (100), comprising: a motor unit (110) comprising: a first part (120); a second part (130) movable relative to the first part (120); a plurality of spaced activatable motor elements (140) provided on the first part (120), each activatable motor element (140) being operative when activated by application of an electric current thereto for creating relative movement between the first and second parts (120, 130); and a plurality of power electronics drive modules (150), each power electronics drive module (150) being operatively associated with a different subset of the plurality of activatable motor elements (140) and comprising a power converter (155) operative to convert direct current into a periodic current for powering the activatable motor elements (140); and a power supply arrangement (170) comprising: at least one direct current power source (180); and a plurality of n parallel direct current power supply lines (190), each of the parallel direct current power supply lines (190) being operative to transmit direct current from the at least one direct current power sources (180) to a different subset of the plurality of power electronics drive modules (150).