Motor Driven Compressor Thermal Management
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Solution Overview
Problem
Motor-driven compressors face malfunctions due to excessive temperature of the drive circuit, which can exceed or drop below its operational range, leading to potential continuous operation disruptions.
Innovation Solution
Incorporating a temperature measuring section and a modulation method controller that adjusts the drive circuit's modulation method between three-phase and two-phase modulation, with distinct high-temperature stop temperatures to prevent overheating and maintain the drive circuit within a safe operational range.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Duration of action of stationary object
If the drive circuit operates without temperature control, then the compressor can run continuously, but the drive circuit temperature may exceed the upper limit of the guaranteed operation range causing malfunction
Solution Approach 1:
The system performs preliminary temperature monitoring and proactive shutdown before the drive circuit temperature exceeds the upper limit of the guaranteed operation range. The temperature measuring section continuously measures the drive circuit temperature, and when it reaches or exceeds the HT stop temperature, the HT stop controller shuts down the electric motor in advance, preventing thermal damage and ensuring reliable operation.
Solution Approach 2:
The system implements a feedback control mechanism where the temperature measuring section continuously monitors the drive circuit temperature and feeds this information back to the HT stop controller. Based on this feedback, the controller dynamically adjusts operation by shutting down the motor when the temperature reaches the HT stop temperature, creating a closed-loop temperature management system that balances continuous operation with reliability.
2Loss of energy
If the drive circuit temperature is allowed to drop below the lower limit of the guaranteed operation range, then energy efficiency may improve, but the drive circuit may malfunction due to excessive cold
Solution Approach 1:
The system performs preliminary temperature monitoring and proactive shutdown before the drive circuit temperature drops below the lower limit of the guaranteed operation range. The temperature measuring section continuously monitors the temperature, and when it reaches or falls below the LT stop temperature, the LT stop controller shuts down the electric motor in advance, preventing cold-related malfunction and ensuring reliable operation.
Solution Approach 2:
The system implements a feedback control mechanism where the temperature measuring section continuously monitors the drive circuit temperature and feeds this information back to the LT stop controller. Based on this feedback, the controller dynamically adjusts operation by shutting down the motor when the temperature reaches the LT stop temperature, creating a closed-loop temperature management system that balances energy efficiency with reliability.
3Device complexity
If a single HT stop temperature is used for both three-phase and two-phase modulation, then the control system is simpler, but the compressor cannot operate continuously in cold environments when using two-phase modulation
Solution Approach 1:
The system dynamically adjusts the HT stop temperature based on the modulation method being used. The HT stop temperature setting section sets the HT stop temperature to a first value when three-phase modulation is active and to a second value (higher than the first) when two-phase modulation is active. This dynamic adjustment allows the compressor to operate continuously in cold environments during two-phase modulation while maintaining simple control logic through predefined temperature thresholds.
Solution Approach 2:
The system changes the temperature parameter (HT stop temperature) based on the modulation method. By setting different HT stop temperatures for three-phase and two-phase modulation, the system adapts to the different thermal characteristics of each modulation mode, enabling continuous operation in cold environments during two-phase modulation while keeping the control system relatively simple through predefined parameter values.
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 solution allows the motor-driven compressor to operate continuously by effectively managing temperature extremes, preventing overheating or underheating of the drive circuit, thus ensuring stable operation.
Implementation Method 1
a temperature measuring section that measures a temperature of the drive circuit
Implementation Method 2
heat exchange takes place between the fluid and the drive circuit via the housing to cool the drive circuit
Data Source
AI summary
A motor-driven compressor includes an electric motor, a drive circuit, a modulation method controller, a temperature measuring section, a high-temperature (HT) stop controller, and a high-temperature (HT) stop temperature setting section. The high-temperature (HT) stop controller stops the electric motor when the temperature measured by the temperature measuring section is higher than or equal to a predetermined high-temperature (HT) stop temperature. When the modulation method is the three-phase modulation, the HT stop temperature setting section sets the HT stop temperature to a three-phase high-temperature (HT) stop temperature. When the modulation method is the two-phase modulation, the HT stop temperature setting section sets the HT stop temperature to a two-phase high-temperature (HT) stop temperature, which is higher than the three-phase HT stop temperature.