Motor Control Device Stabilizing Response Time via Voltage-Adaptive PID
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Solution Overview
Problem
The responsiveness of motors controlled using PID control is affected by fluctuations in input voltage, leading to variations in response time due to the dependence of output voltage change speed on input voltage, resulting in unstable motor performance.
Innovation Solution
A control device that includes difference calculation circuitry, coefficient correction circuitry, output voltage determination circuitry, and signal generation circuitry, which calculates and adjusts the proportional and integral coefficients based on the ratio of reference voltage to current input voltage, stabilizing the output voltage control by correcting the coefficients to maintain consistent response time regardless of input voltage fluctuations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If PID control is used to control motor rotation speed, then the motor rotation speed can be controlled to obtain target rotation speed, but the responsiveness of the motor fluctuates due to input voltage variations
Solution Approach 1:
The patent changes the parameters (proportional and integral coefficients) of the PID control based on the input voltage level. When input voltage varies, the coefficients are adjusted accordingly to maintain consistent motor responsiveness. This resolves the contradiction by adapting the control parameters to compensate for voltage fluctuations, ensuring stable responsiveness while maintaining speed control capability.
2Speed
If the output voltage of the inverter is adjusted through PID control, then the motor rotation speed can be controlled, but the speed at which the output voltage changes depends on the input voltage
Solution Approach 1:
The patent adjusts the PID coefficients based on input voltage to maintain consistent response characteristics. By changing the proportional and integral coefficients according to input voltage levels, the system ensures that the output voltage changes at a consistent rate regardless of input voltage variations, resolving the contradiction between speed control and response time consistency.
Solution Approach 2:
The patent implements feedback by monitoring the input voltage and adjusting the PID coefficients accordingly. This feedback mechanism ensures that when input voltage changes, the control parameters are automatically adjusted to maintain consistent response characteristics, resolving the contradiction between output voltage change speed and response time consistency.
Data Source
AI summary
A control device of a motor includes difference calculation circuitry that calculates a difference between a current rotation speed and a target rotation speed of the motor, coefficient correction circuitry that outputs corrected proportion coefficient and integration coefficient by multiplying each of an initially set proportion coefficient and integration coefficient by a correction coefficient, output voltage determination circuitry that calculates at least one of a proportional term in which the difference is multiplied by the corrected proportion coefficient and an integral term in which the difference is multiplied by the corrected integration coefficient and the result is integrated and determines one of the proportional term and the integral term or the sum of the two terms as a control value of the output voltage, and signal generation circuitry that generates a control signal on the basis of the control value.