Rotating Electric Machine Control Device Overheat Protection
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Solution Overview
Problem
Conventional electric power steering control devices lack effective overheat protection mechanisms for plural sets of drivers and winding groups, particularly when one system experiences abnormality, leading to potential overheating and system failure.
Innovation Solution
A rotating electric machine control device with plural inverter units and a control unit that includes an electric current controller, overheat protection controller, and abnormality detector. The overheat protection controller estimates system and shared component temperatures to calculate restricted current values, ensuring safe operation by adjusting current limits when abnormalities occur.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If one system experiences abnormality and the drive is continued using the remaining normal system, then the productivity is maintained, but the temperature of the normal system and shared components increases leading to potential overheating
Solution Approach 1:
The patent implements dynamic temperature estimation and restricted current value calculation that adapts to system conditions. When one system is abnormal, the controller dynamically changes the temperature estimation model to account for increased thermal load on the normal system and shared components, and adjusts the restricted current values in real-time to prevent overheating while maintaining continuous operation.
Solution Approach 2:
The patent changes operational parameters (restricted current values) based on the abnormal system detection. The controller calculates different restricted current values for the normal system compared to the abnormal system, and adjusts these parameters dynamically based on temperature estimation to manage thermal conditions while maintaining productivity.
2Reliability
If the restricted current value is calculated based on temperature estimation when one system is abnormal, then the overheat protection is improved, but the device complexity increases
Solution Approach 1:
The patent implements a self-service control mechanism where the controller automatically detects system abnormalities, estimates temperatures, calculates appropriate restricted current values, and adjusts operation without external intervention. The abnormality detector, temperature estimator, and restricted current calculator work autonomously to provide overheat protection, reducing the need for additional hardware sensors or complex external control systems.
Solution Approach 2:
The controller performs multiple functions using the same hardware resources: it acts as an abnormality detector, temperature estimator, and current controller. The temperature estimator uses the same processing unit to estimate both system temperatures and shared component temperatures, and the restricted current calculator adjusts current limits for multiple systems based on a unified thermal model, reducing device complexity through functional integration.
Data Source
AI summary
A rotating electric machine control device includes a first system controller and a second system controller, an overheat protection controller and an abnormality detector. The overheat protection controller includes a temperature estimator and a restricted current calculator. The temperature estimator estimates system temperatures as well as other temperature, including a shared component temperature of a shared component that is connected to both of plural systems in a shared manner. The restricted current calculator calculates restricted current values, based on the system temperatures and the shared component temperature. At least one of the system temperatures, the shared component temperature, and/or the restricted current values is changed from an all-systems normal time, when at least one of a plurality of systems is abnormal.