Open-End Winding Inverter Switching for Torque-Efficient Motor Drive
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Solution Overview
Problem
Existing motor driving technologies face challenges in maximizing inverter-motor power conversion efficiency, leading to degraded fuel efficiency and limited motor torque, especially when covering both low-output and high-output ranges with a single motor.
Innovation Solution
A motor driving apparatus with integrated inverters and a switch that can switch between closed-end and open-end winding modes, allowing efficient torque generation across different driving conditions without the need for separate modules.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Force
If the motor winding number is increased to increase the motor maximum torque, then the maximum motor torque is improved, but the range having a high voltage usage ratio becomes far from the low-torque area, degrading the fuel efficiency
Solution Approach 1:
The motor driving apparatus segments the control into two independent inverters (first inverter for high-torque area, second inverter for low-torque area) that can operate separately or in combination. This segmentation allows each inverter to be optimized for specific torque ranges, maintaining high voltage usage ratio across different operating conditions while achieving high maximum torque when needed.
2Use of energy by moving object
If a major driving point is designed to be included in the range having a high voltage usage ratio from the viewpoint of fuel efficiency, then the fuel efficiency is improved, but the maximum motor torque is limited, degrading the accelerating/starting performance of the vehicle
Solution Approach 1:
The system dynamically switches between different inverter configurations based on the required torque level. The controller selectively activates the first inverter, second inverter, or both in combination, allowing the system to adapt its voltage usage ratio and torque output to match real-time driving conditions. This dynamic control enables high fuel efficiency during normal operation while maintaining the capability for high maximum torque when accelerating or starting.
3Adaptability or versatility
If two inserters and a mode-switching switch are used to drive a single motor in two different modes, then both low-output and high-output ranges are covered, but the device complexity increases
Solution Approach 1:
The patent merges the functionality of two separate inverters into a unified motor driving apparatus with integrated control. The first and second inverters share common components (DC power source, controller, motor connection points) and can operate independently or in combination. This merging approach reduces overall system complexity compared to completely separate systems while maintaining the ability to cover both low-output and high-output ranges through coordinated operation of the integrated inverter units.
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
Enhances system efficiency by optimizing voltage usage ratio, improving fuel efficiency and motor performance across varying output ranges.
Implementation Method 1
a switch inside the inverter is turned ON/OFF by pulse width modulation control and applies a line voltage to the Y-connected motor windings such that, by generating an AC current, a torque is generated
Implementation Method 2
a changeover switch and to provide the AC voltage corresponding to each of the phases to a second end of the plurality of windings based on information indicating whether the changeover switch is turned on
Data Source
AI summary
A motor driving apparatus includes a motor including windings respectively corresponding to a plurality of phases, a first inverter including at least one first power module and providing an AC voltage corresponding to each of the phases to one end of the windings, a second inverter including a plurality of second power modules each including a changeover switch and providing the AC voltage corresponding to each of the phases to the other end of the windings based on information indicating whether the changeover switch is turned on, and a controller connected to the changeover switch and configured to control whether the changeover switch is turned on according to a motor driving mode, wherein each of the second power modules has a changeover terminal to which a first end of the changeover switch is connected, and the changeover terminals of the plurality of second power modules are short-circuited to each other.