Inverter Regenerative Current Switching Redundancy
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Solution Overview
Problem
In vehicles with motor-driven systems, such as hybrid and electric vehicles, the failure of rotation sensors complicates control selection between shutdown and active short circuit controls during motor regenerative operations, as existing systems rely on sensor-determined rotation speed thresholds for state switching.
Innovation Solution
An inverter device with a motor, power supply, inverter, first and second detectors, and a determiner that switches between regenerative current return to the motor and supply to the power supply based on detection results, ensuring redundancy and accurate state switching even if one of the detectors fails, using voltmeters for detection and a CPU for determination.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a single detection unit is used to determine switching between regenerative states, then the device complexity is reduced, but the reliability deteriorates due to inability to provide redundancy when detection unit fails
Solution Approach 1:
The patent assigns different detection functions to different detection units: the first detection unit detects voltage across the capacitor to determine inverter output voltage, while the second detection unit detects voltage across the battery to determine power supply voltage. This localized functional differentiation enables redundancy without requiring complete duplication of the entire detection system, thus improving reliability while controlling device complexity.
Solution Approach 2:
The patent implements a determination unit that can identify when the first detection unit has failed and automatically switch to using detection results from the second detection unit. This beforehand cushioning mechanism ensures that the system maintains operational reliability even when one detection unit fails, without requiring immediate system shutdown or complex error handling procedures.
2Reliability
If rotation sensor-based control selection is used, then the ease of operation is improved, but the reliability deteriorates when the rotation sensor fails
Solution Approach 1:
The patent replaces the mechanical rotation sensor-based control selection with an electrical detection system that monitors voltage conditions across the capacitor and battery. The determination unit uses these electrical measurements to automatically select appropriate regenerative control modes (motor braking or battery charging), eliminating dependence on rotation sensors while maintaining ease of operation through automatic electronic control.
Solution Approach 2:
The inverter device performs self-diagnosis and self-adjustment by using the determination unit to monitor detection unit status and automatically switch between detection sources when failures occur. This self-service capability ensures continuous reliable operation without requiring external intervention or complex manual troubleshooting, thereby maintaining ease of operation while improving reliability.
Data Source
AI summary
An inverter device includes a motor, a power supply that supplies the motor with electric current, an inverter that, during regenerative operation of the motor, performs switching between a first state in which regenerative current generated in the motor is returned to the motor again and a second state in which the regenerative current is supplied to the power supply, a first detector that detects a first condition electrically acting on the inverter, a second detector that detects a second condition electrically acting on the power supply, and a determiner that performs a first determination to perform switching between the first state and the second state, based on a detection result by the first detector or the second detector.