Dual Inverter Neutral-Point Switching for Balanced Device Load
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Solution Overview
Problem
The dual inverter system in existing technologies results in an imbalance of cumulative loads between upper and lower switching devices when creating a neutral point in the second inverter, leading to inefficient load distribution.
Innovation Solution
A dual inverter system with a controller that selects between an upper short-circuiting circuit and a lower short-circuiting circuit based on load comparison, using temperature, driving time, or count of times to evenly distribute load among switching devices.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If all upper switching devices of the second inverter are turned on to create a neutral point, then the motor can be driven in single mode, but the cumulative load becomes imbalanced between upper and lower switching devices
Solution Approach 1:
The patent applies dynamics by making the switching device configuration adjustable rather than fixed. The controller dynamically selects between upper short-circuiting circuit and lower short-circuiting circuit configurations based on real-time load conditions, transforming a static neutral point creation method into a dynamic adaptive system that optimizes load distribution.
Solution Approach 2:
The patent changes the operational parameters of the switching devices by alternating between two distinct configuration states (upper short-circuiting and lower short-circuiting circuits). This parameter change allows the system to adapt the neutral point creation method based on cumulative load conditions, thereby balancing the workload across different switching devices over time.
2Ease of operation
If all lower switching devices of the second inverter are turned on to create a neutral point, then the motor can be driven in single mode, but the cumulative load becomes imbalanced between upper and lower switching devices
Solution Approach 1:
The system dynamically switches between lower short-circuiting circuit configuration and upper short-circuiting circuit configuration based on cumulative load monitoring. This dynamic adaptation ensures that when lower switching devices are used to create the neutral point, the system can later switch to upper switching devices to rebalance the load, maintaining long-term reliability.
Solution Approach 2:
The controller changes the operational state of the switching devices by alternating between lower short-circuiting and upper short-circuiting configurations. This parameter change strategy allows the system to distribute cumulative load evenly across all switching devices while maintaining the ability to operate in single mode.
3Adaptability or versatility
If the second inverter is used to create a neutral point by holding switching devices on, then single mode operation is enabled, but the load distribution among switching devices becomes uneven
Solution Approach 1:
The patent implements periodic action by alternately switching between upper short-circuiting circuit mode and lower short-circuiting circuit mode over time. This periodic alternation ensures that no single group of switching devices bears the cumulative load continuously, thereby distributing wear and heat generation evenly across all switching devices while maintaining operating mode flexibility.
Solution Approach 2:
The system employs feedback mechanisms by monitoring the cumulative load of switching devices and using this information to make intelligent decisions about which configuration to select. The controller receives feedback on load distribution and adjusts the switching device states accordingly, ensuring balanced utilization and enhanced reliability while preserving adaptability.
Data Source
AI summary
The dual inverter system includes a first inverter connected to one end of a stator coil of the motor and a second inverter connected to the other end. The controller is capable of executing a single mode in which the second inverter is disconnected from the battery and the motor is driven only by the first inverter. When driving the motor in a single mode, the controller selects one of an upper short-circuiting circuit that turns on all the upper SW devices of the second inverter and turns off all the lower SW devices, and a lower short-circuiting circuit that turns on all the lower SW devices of the second inverter and turns off all the upper SW devices. The controllers compare the loads of the upper SW devices and the lower SW devices of the second inverters.