Dynamic Mask Time Adjustment for Motor Noise Suppression
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Solution Overview
Problem
Existing motor driving devices face instability in motor control due to noise from ON and OFF operations of switching elements, particularly when the set current is changed, as fixed mask times fail to adapt to varying power supply voltages and current values.
Innovation Solution
A motor driving device with a mask processor that dynamically sets mask times based on power supply voltage and current values, preventing noise interference by disabling control during specific mask periods, thereby stabilizing motor operation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If a fixed mask time is used to prevent noise from switching elements, then noise interference is reduced, but motor control stability deteriorates when set current changes
Solution Approach 1:
The mask time is changed dynamically based on the relationship between power supply voltage and current value. Specifically, when the power supply voltage is high and the current value is low, a longer mask time is applied, and when the power supply voltage is low and the current value is high, a shorter mask time is applied. This dynamic adjustment resolves the contradiction by adapting the noise suppression duration to the actual operating conditions, maintaining control stability across varying current settings while still preventing noise interference.
Solution Approach 2:
The invention changes the mask time parameter according to variations in power supply voltage and current value. By establishing a correspondence between these parameters and appropriate mask times, the system optimizes the balance between noise suppression and control stability. This parameter change approach allows the mask time to be neither too long (which would cause control instability) nor too short (which would fail to suppress noise effectively) under different operating conditions.
2Object-affected harmful factors
If the mask time is extended to better suppress noise, then noise interference is reduced, but control response time is delayed
Solution Approach 1:
The mask time is adjusted dynamically based on real-time operating conditions (power supply voltage and current value). Instead of using a uniformly extended mask time that would always delay control response, the system applies longer mask times only when necessary (high voltage, low current conditions where noise is more problematic), and shorter mask times when the operating conditions make noise less of an issue. This resolves the contradiction by making the time loss conditional rather than constant.
Solution Approach 2:
The mask time parameter is changed according to the specific operating point of the motor driver. By establishing optimal mask time values for different combinations of power supply voltage and current value, the system achieves effective noise suppression without unnecessarily extending the mask time in conditions where it would cause excessive control response delay.
3Productivity
If the mask time is reduced to improve control response, then control response time is improved, but noise suppression capability is reduced
Solution Approach 1:
The mask time is made dynamic and adapts to operating conditions. When control response speed is critical (such as during high current operations), the system automatically reduces the mask time to minimize response delay. When noise suppression is more critical (such as during low current, high voltage operations), the system increases the mask time. This dynamic behavior resolves the contradiction by allowing the mask time to be short when needed for response speed and long when needed for noise suppression.
Solution Approach 2:
The mask time parameter is optimized for different operating conditions. Instead of using a fixed conservative value that would suppress noise but slow down control response, the system changes the mask time parameter based on the relationship between power supply voltage and current value, achieving both fast control response and adequate noise suppression across the full operating range.
Data Source
AI summary
A motor driving device according to embodiments includes a driving circuit, a controller, and a mask processor. The driving circuit switches, a voltage applied to a motor, according to a switching operation by plural switching elements, for a first switching operation and a second switching operation, and to control driving of the motor. The controller controls the driving circuit on the basis of timing when an electric current flowing to the motor exceeds a predetermined current value. The mask processor sets a predetermined mask time in the switching operation by the control of the driving circuit and enables a change of the predetermined mask time on the basis of at least one of a power supply voltage and the predetermined current value.