Motor Control Apparatus Voltage Command Priority Switching
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Solution Overview
Problem
Existing motor control systems face challenges in smoothly switching between high-pole-number and low-pole-number drives, leading to overcurrent and large torque variations due to the inability to output the required voltage, causing instability and torque fluctuations.
Innovation Solution
A motor control apparatus with a high-pole-number controller, low-pole-number controller, and priority pole-number determiner that calculates and prioritizes voltage commands to ensure the electric motor can operate within the capabilities of the power source, preventing overcurrent and torque variations by generating second voltage commands that can be simultaneously outputted during switching.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If switching between high-pole-number drive and low-pole-number drive is performed by gradually increasing one current command and decreasing the other, then the switching process is smoothed, but overcurrent and large torque variations still occur due to inability to output required voltage
Solution Approach 1:
The patent changes the control parameter from current commands to voltage commands. By calculating voltage commands for both high-pole-number and low-pole-number drives and selecting the appropriate one based on voltage saturation conditions, the system avoids overcurrent and torque variations during switching. This parameter change enables the controller to output the required voltage while maintaining switching stability.
Solution Approach 2:
The patent implements dynamic switching between high-pole-number and low-pole-number drives based on real-time voltage saturation detection. The controller dynamically adjusts which drive mode is active by comparing voltage commands with saturation thresholds, enabling smooth transitions without overcurrent or torque variations.
2Productivity
If voltage commands for both high-pole-number and low-pole-number drives are calculated independently, then each drive mode can be optimized, but the system cannot output both voltage commands simultaneously causing instability
Solution Approach 1:
The patent calculates voltage commands for both high-pole-number and low-pole-number drives (excessive action) but only outputs one at a time based on voltage saturation conditions. This partial output approach allows the system to maintain optimized control for each drive mode while avoiding the instability caused by attempting to output both simultaneously.
Solution Approach 2:
The patent introduces a voltage saturation detection mechanism as an intermediary between the two drive modes. This intermediary determines which voltage command can be output based on saturation thresholds, enabling the system to optimize both drive modes while maintaining stability through selective output.
3Adaptability or versatility
If the electric motor switches between high-pole-number and low-pole-number drives, then the motor can operate across a wider speed and torque range, but torque fluctuations and current responsiveness deteriorate during switching
Solution Approach 1:
The patent performs preliminary calculation of voltage commands for both high-pole-number and low-pole-number drives before switching occurs. By determining the appropriate drive mode in advance based on voltage saturation conditions and pre-calculating the corresponding voltage command, the system avoids torque fluctuations and maintains current responsiveness during transitions.
Solution Approach 2:
The patent implements feedback through voltage saturation detection that monitors the actual voltage output capability. This feedback mechanism adjusts the selection between high-pole-number and low-pole-number drive modes in real-time, ensuring smooth transitions without torque fluctuations while maintaining the wide operating range.
Data Source
AI summary
A motor control apparatus includes: a high-pole-number controller that generates a voltage command for high-pole-number drive of an electric motor and controls operation of the electric motor under the high-pole-number drive; a low-pole-number controller that generates a voltage command for low-pole-number drive of the electric motor and controls operation of the electric motor under the low-pole-number drive; and a priority pole-number determiner that determines which one of the high-pole-number drive and the low-pole-number drive is to be given priority during switching between the high-pole-number and low-pole-number drives. Moreover, during the switching, of the high-pole-number and low-pole-number controllers, the controller corresponding to the drive given priority by the priority pole-number determiner calculates the voltage command for the drive given priority; and the controller corresponding to the drive not given priority calculates, based on the voltage command for the drive given priority, the voltage command for the drive not given priority.