Electric Motor Drive Controller Abnormal Energization Torque Compensation
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Solution Overview
Problem
Existing drive controllers for electric motors with multi-phase coil sets face challenges in accurately compensating for braking torque during abnormal energization, as all switching elements being turned OFF results in half-wave braking current, making it difficult to control the normal energization system effectively.
Innovation Solution
A drive controller that includes a first control unit to turn ON at least one high-potential or low-potential side switching element in the failed energization system to reduce phase-to-phase impedance, and a second control unit to control the normal energization system based on the torque generated in the abnormal system, allowing for continuous braking current and accurate torque calculation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If all switching elements in the failed energization system are turned OFF, then the failed system stops driving the motor, but braking current flows in a half-wave form making it difficult to control the normal system with high accuracy
Solution Approach 1:
The patent changes the state of switching elements from all OFF to a specific combination of ON and OFF states. By turning ON the high-potential side switching element of the failed phase while keeping the low-potential side switching element OFF, the system transforms the braking current from half-wave to continuous full-wave, enabling accurate torque control.
Solution Approach 2:
Instead of the conventional approach of turning OFF all switching elements in the failed system, the patent inverts the strategy by turning ON the high-potential side switching element. This reverse approach allows continuous current flow through the parasitic diode of the low-potential side switching element, solving the half-wave current problem.
2Object-affected harmful factors
If all switching elements are turned OFF to stop the failed system, then safety is improved, but the braking current shows half-wave form which complicates control
Solution Approach 1:
The patent simplifies control by changing the switching element states to a specific pattern (high-potential ON, low-potential OFF). This produces continuous full-wave braking current that is easier to control and calculate, reducing control program complexity while maintaining safety.
3Reliability
If switching elements are controlled to cancel braking torque, then motor driving is protected, but the half-wave braking current makes high accuracy control difficult
Solution Approach 1:
By changing the switching element states to enable continuous full-wave braking current, the patent improves measurement precision for torque calculation. The continuous current waveform provides more accurate and stable signals for calculating braking torque, enabling high-accuracy control while maintaining motor protection.
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
Enables accurate calculation and compensation of braking torque, improving the control accuracy of the energization system and simplifying the control program, reducing development costs and product complexity.
Implementation Method 1
executing control to turn ON at least one of the high-potential side switching element and the low-potential side switching element in a failed one out of the energization systems, which involves abnormal energization that a potential of the coil reaches a power supply potential or a ground potential, so as to reduce a phase-to-phase impedance
Implementation Method 2
braking current flows from a short-circuited switching element of a given phase to an element of another phase along a channel direction of a parasitic diode of the switching element, whereas current flow from the switching element of the other phase to the failed one is blocked by the parasitic diode of the switching element controlled into OFF state
Implementation Method 3
a torque generated in the energization system involving the abnormal energization
Data Source
AI summary
The present invention relates to drive controller and control method for an electric motor equipped with coil sets corresponding to plural phases. The drive controller and control method for an electric motor of the present invention control, in case of abnormal energization that a potential of the coil reaches a power supply potential or a ground potential, at least one of a high-potential side switching element and a low-potential side switching element in a failed energization system involving the abnormal energization into ON state so as to reduce a phase-to-phase impedance and also, detect a braking torque generated in the energization system involving the abnormal energization to control an output of a normal energization system not suffering from the abnormal energization based on the detected braking torque.