Motor Driving Device Voltage Fluctuation Control
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Solution Overview
Problem
Conventional motor driving devices experience unstable motor control and risk of overcurrent due to sudden fluctuations in power supply voltage, particularly during temporary power disconnections or transitions, which can lead to motor acceleration instability and increased torque.
Innovation Solution
A motor driving device with a PWM duty generator, current detector, power supply voltage sudden fluctuation detector, and current limit value correction unit that adjusts the current limit value or PWM duty value based on detected power supply voltage fluctuations to prevent sudden increases in motor driving current, ensuring stable motor operation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the power supply voltage suddenly fluctuates in a rising direction, then the motor driving current increases suddenly, but this causes unstable motor control and potential overcurrent
Solution Approach 1:
The power supply voltage sudden fluctuation detector proactively detects voltage fluctuations before they cause harmful effects. By detecting the rising edge of power supply voltage and calculating fluctuation amplitudes in advance, the system can preemptively adjust the current limit value or PWM duty value to prevent overcurrent and unstable motor control, rather than reacting after the problem occurs
Solution Approach 2:
The system continuously monitors the power supply voltage and compares it against reference values to detect fluctuations. Based on this feedback, the current limit value setting unit or PWM duty generator dynamically adjusts control parameters to maintain stable motor operation even when voltage fluctuates, creating a closed-loop control system that adapts to changing conditions
2Object-affected harmful factors
If the current limit value is reduced to prevent overcurrent, then overcurrent is prevented, but the motor driving capability is reduced
Solution Approach 1:
Instead of using a fixed current limit value, the system dynamically adjusts the current limit value or PWM duty value based on the detected power supply voltage fluctuation amplitude. When voltage fluctuates, the limit is temporarily reduced to prevent overcurrent; when voltage is stable, the limit returns to normal to maintain full motor driving capability. This dynamic adjustment resolves the contradiction by making the current limit adaptive rather than static
Solution Approach 2:
The system changes the current limit value or PWM duty value parameter based on power supply voltage conditions. By calculating the fluctuation amplitude and adjusting these parameters accordingly, the system prevents overcurrent during voltage fluctuations while maintaining normal motor performance during stable operation, effectively resolving the trade-off between safety and performance
Data Source
AI summary
The present disclosure provides a motor driving device capable of inhibiting unstable driving of a motor even in the occurrence of a sudden fluctuation of a power supply voltage. The motor driving device includes a power supply voltage sudden fluctuation detector, a power supply voltage fluctuation width generator and a current limit value setting unit. The power supply voltage sudden fluctuation detector detects a sudden fluctuation in a direction in which the power supply voltage rises. The power supply voltage fluctuation width generator detects a fluctuation width of the power supply voltage. When the sudden fluctuation is detected by the power supply voltage sudden fluctuation detection unit, a current limit value of the current limit value setting unit is reduced from a normal value and corrected by the correction width corresponding to the fluctuation width of the detected power supply voltage.