Electric Motor Drive Controller Torque Control
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing drive controllers for electric motors with multiple energization systems struggle to uniformly control braking torque due to varying impedance at faulted portions, leading to inconsistent motor torque and difficulty in matching target values.
Innovation Solution
A drive controller with current detecting units, inverter setting units, and torque detecting units that detect currents and torque in abnormal energization systems, allowing for precise control and impedance consideration to improve motor controllability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the inverter in a normal system is controlled to cancel braking torque without considering impedance variations, then the control process is simple, but the braking torque cancellation is inconsistent and motor torque does not match target value
Solution Approach 1:
The patent implements feedback control by detecting the actual braking torque generated in the failed energization system and using this information to adjust the control of the normal energization system. The torque detecting unit measures the braking torque based on current detection, and this feedback is used to precisely control the normal system to cancel the detected braking torque, ensuring accurate torque matching.
Solution Approach 2:
The patent changes the control parameters of the normal energization system based on the detected impedance characteristics of the failed system. By adjusting the current commands and torque control parameters according to the specific impedance conditions of the fault, the system achieves consistent braking torque cancellation across different fault types while maintaining controllable complexity.
2Reliability
If all MOSFETs in the failed system are turned OFF to stop the failed system, then the fault isolation is effective, but the braking torque varies according to fault type and cannot be controlled uniformly
Solution Approach 1:
The patent applies local quality by turning OFF only the specific MOSFETs in the failed energization system that are necessary for isolation, while keeping other MOSFETs in appropriate states to control braking torque. This selective switching approach maintains reliable fault isolation while preserving the ability to adaptively control braking torque based on the specific fault condition detected by the torque detecting unit.
Solution Approach 2:
The patent implements dynamic control by adjusting the state of MOSFETs and control parameters based on the detected fault type and impedance characteristics. The system transitions from static fault isolation to dynamic adaptive control, where the normal energization system's MOSFETs are controlled in real-time to cancel the braking torque that varies with different fault conditions, achieving both reliability and adaptability.
3Productivity
If the braking current is detected without considering impedance at the short-circuited portion, then the detection process is simple, but the braking torque varies and uniform control cannot be achieved
Solution Approach 1:
The patent replaces direct mechanical torque measurement with electrical parameter-based torque detection. The torque detecting unit calculates braking torque by measuring electrical currents in the failed energization system and using the known impedance characteristics, substituting complex mechanical measurement with electrical sensing and calculation. This maintains fast response speed while achieving accurate torque measurement that accounts for impedance variations.
Data Source
AI summary
To provide drive controller and control method for an electric motor including plural energization systems composed of an inverter and coils corresponding to plural phases. The controller includes: a current detecting unit for detecting currents between the coils and output points of the inverter or between the coils and a connection point between the coils; an inverter setting unit for controlling an inverter of the energization system involving abnormal energization into a predetermined condition; a torque detecting unit for detecting a torque generated in the energization system involving the abnormal energization based on a current in the energization system, which is detected by the current detecting unit; and a control unit for controlling a normal inverter based on the torque detected by the torque detecting unit. This configuration enhances the performance of controlling the electric motor in case a braking torque is generated due to abnormal energization.