Hybrid Drive Control Preventing Motor Generator Over-Speed
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Solution Overview
Problem
Existing hybrid vehicle drive control technologies fail to effectively prevent motor generator over-speeds, particularly due to limitations in torque control and communication abnormalities, leading to inadequate torque production and system instability.
Innovation Solution
A drive control apparatus and method that includes a target engine torque setter, motor torque command value calculator, and engine torque corrector, which calculates and adjusts target engine torque based on permissible output torque and torque command values to prevent motor generator over-speeds by setting a target engine torque correction value, ensuring stable engine operation and minimizing unnecessary torque suppression.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Force
If the motor generator is operated at high revolution numbers to meet torque demands, then the torque output capability is improved, but the motor generator enters an over-speed state where permissible output torque decreases toward zero
Solution Approach 1:
The system performs preliminary action by detecting the torque command value for the motor generator in advance and comparing it with the permissible output torque at the current revolution number. When the torque command exceeds permissible output torque, the system proactively reduces the target engine revolution number before over-speed occurs, preventing the motor generator from entering an unsafe operating state while maintaining torque delivery capability.
2Speed
If the target engine revolution number is reduced to prevent motor generator over-speed, then the motor generator speed is controlled, but the engine torque may be unnecessarily suppressed affecting vehicle performance
Solution Approach 1:
The system applies local quality by implementing targeted torque management. Instead of uniformly reducing engine torque across all operating conditions, the control unit specifically adjusts the target engine revolution number only when and where needed - namely when the motor generator's torque command value exceeds its permissible output torque at the current speed. This localized intervention maintains engine torque in normal operating conditions while preventing over-speed only when necessary.
Solution Approach 2:
The system utilizes parameter changes by dynamically adjusting the target engine revolution number based on real-time comparison between the motor generator's torque command value and its permissible output torque. The control unit modifies the engine revolution number parameter selectively - reducing it only when the torque command exceeds permissible output torque at the current motor generator speed, thereby maintaining optimal performance across varying operating conditions.
3Reliability
If existing control technologies are used to prevent motor generator over-speed, then some over-speed protection is achieved, but the control range is limited by fixed allowance values or communication abnormality conditions
Solution Approach 1:
The system implements dynamics by transitioning from static, fixed allowance values to dynamic, real-time torque management. The control unit continuously detects the motor generator's torque command value and compares it with the permissible output torque at the current revolution number. This dynamic approach adapts to varying operating conditions, enabling effective over-speed prevention across the entire operating range rather than being constrained by predetermined fixed values or specific communication abnormality scenarios.
Data Source
AI summary
A drive control apparatus for hybrid vehicles adapted to facilitate controlling a rotation speed of an internal combustion engine, preventing excess speeds of a motor generator. The drive control apparatus for hybrid vehicles is adapted for a drive control of a vehicle using outputs from an engine and motor generators, and includes a target engine operating point setter for setting up a target engine operating point to determine target engine torque and a target engine rotation speed of the engine from target engine power and an efficiency of system. A motor torque command value calculator sets up respective torque command values of the motor generators, and an engine torque corrector corrects the target engine torque by a target engine torque correction value set up based on the torque command values of the motor generators and permissible output torque of the motor generators.