Motor Control Device Torque Restriction Based on Refrigerant Temperature
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Solution Overview
Problem
Existing motor control devices for vehicles do not adequately account for refrigerant temperature when protecting inverter devices from overheating during stalls, leading to potential thermal damage or underperformance.
Innovation Solution
A control device that includes refrigerant temperature detection means to adjust the output torque of the motor based on detected refrigerant temperature, ensuring the inverter device operates within safe temperature ranges and maintains performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the current-carrying enabling time is calculated without considering refrigerant temperature, then the inverter device protection is simplified, but the switching elements may be thermally broken when atmosphere temperature is high
Solution Approach 1:
The patent changes the parameter of current-carrying enabling time based on refrigerant temperature. When refrigerant temperature is high, the enabling time is shortened to prevent thermal breakdown; when refrigerant temperature is low, the enabling time can be extended. This dynamic parameter adjustment resolves the contradiction by adapting protection settings to actual thermal conditions without requiring a completely complex control system.
Solution Approach 2:
The patent performs preliminary detection of refrigerant temperature and pre-calculates the appropriate current-carrying enabling time before stall occurs. This preliminary action allows the control system to be ready with appropriate protection settings, avoiding the need for complex real-time adjustments during stall while ensuring switching elements are protected under high temperature conditions.
2Productivity
If the current-carrying enabling time is extended for low temperature operation, then the inverter device performance is improved, but the switching elements may still be damaged if temperature is not considered
Solution Approach 1:
The patent makes the current-carrying enabling time dynamic rather than fixed. The enabling time automatically adjusts based on refrigerant temperature conditions - longer for low temperatures to maintain performance, shorter for high temperatures to ensure safety. This dynamic adaptation resolves the contradiction between productivity and reliability by allowing both optimized performance and protection depending on thermal conditions.
3Reliability
If the current-carrying enabling time is shortened to protect switching elements, then thermal damage is prevented, but the inverter device cannot adequately exhibit its performance
Solution Approach 1:
The patent changes the current-carrying enabling time parameter based on refrigerant temperature. Under low temperature conditions, the enabling time is extended to allow the inverter device to fully exhibit its performance capabilities. Under high temperature conditions, the enabling time is shortened to prevent thermal damage. This parameter adaptation resolves the contradiction by optimizing both protection and performance according to actual thermal conditions.
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
Prevents thermal breakdown of switching elements by adjusting current-carrying time based on refrigerant temperature, allowing the inverter device to operate effectively across varying environmental conditions.
Implementation Method 1
refrigerant temperature detection means that detects a refrigerant temperature of a heat exchanger for heat exchange with the inverter device
Data Source
AI summary
A control device for a motor that drives a vehicle and controls the motor by controlling an inverter device that converts a direct voltage, supplied from a direct current source, into an alternating voltage to be supplied to the motor, the control device having a refrigerant temperature detector that detects a refrigerant temperature of a heat exchanger for heat exchange with the inverter device, and a torque restrictor that restricts an output torque of the motor when the inverter device is put in a predetermined state, wherein the torque restrictor changes restrictions on the output torque on the basis of the refrigerant temperature detected by the refrigerant temperature detector.