Motor Control System Dead Time Compensation
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Motor control systems experience waveform distortion due to 'dead time' when using complementary switch control circuits, which is not fully mitigated by subtraction operations between control signals with phase differences.
Innovation Solution
A motor control system with a Y-shaped configuration of coils and switches, where control signals are adjusted to have a constant value and mirror-symmetrical waveforms, generating PWM signals based on triangle waves to minimize waveform distortion by canceling out dead time effects through subtraction operations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If complementary switch control circuits are used to control motor control signals, then the switching operation can be controlled, but waveform distortion occurs due to dead time between upper-side and lower-side switches
Solution Approach 1:
The patent applies preliminary anti-action by pre-compensating for dead time effects in the control signals. Before the subtraction operation, the control signals are adjusted to anticipate the dead time distortion, so that when the subtraction is performed, the distortion effects cancel each other out. This is achieved by modifying the control signals to include pre-calculated compensation values that counteract the expected dead time interference.
Solution Approach 2:
The patent converts the harmful dead time effect into a benefit by utilizing the subtraction operation between two control signals. The dead time distortion present in both signals becomes advantageous because when subtracted, the distortion components cancel each other out, leaving a clean output signal. This transforms the previously harmful dead time into a useful feature that improves waveform quality.
2Measurement precision
If subtraction operation is performed between two control signals with phase difference, then one control signal remains undistorted, but the resulting signal still contains distortion from the other control signal
Solution Approach 1:
The patent applies parameter changes by modifying the control signals before subtraction. The signals are transformed to include dead time compensation parameters, changing their characteristics so that when subtraction occurs, the distortion parameters cancel out. This involves adjusting signal parameters such as timing offsets and amplitude corrections to ensure the distorted components are equal and opposite.
3Reliability
If dead time is introduced in complementary switch control, then switch timing can be managed, but the control wave experiences distortion that affects motor control precision
Solution Approach 1:
The patent introduces an intermediary processing step between the generation of control signals and their application to the switches. This intermediary stage performs the subtraction operation with dead time compensation, acting as a mediator that eliminates distortion while preserving the necessary timing control. The intermediary processor calculates and applies compensation based on the known dead time characteristics of the switching circuit.
Data Source
AI summary
A motor control system includes a motor, a driving module and a control module. A first coil is electrically connected to a first node where a first control signal is provided, a second coil is electrically connected to a second node where a second control signal is provided, and a third coil is electrically connected to a third node where a third control signal is provided. An constant value of the first control signal is not zero, and a lower signal voltage limit of the first control signal is larger than or equal to zero.