PWM Gate Control for Switching Components With Reduced Oscillation
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Solution Overview
Problem
Existing methods for controlling inductive electrical loads like brushless DC motors using pulse-width-modulation (PWM) signals often result in parasitic oscillations, which negatively affect electromagnetic compatibility and increase switching losses, delays, and manufacturing costs.
Innovation Solution
A method and device that modify the control signal by adjusting it to multiple predefined values within each PWM clock period based on detected oscillation amplitudes, shifting switchover instants to limit oscillations, using closed-loop control circuits to counteract oscillations and prevent switching disruptions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If external capacitors, gate resistors, or suppressor circuits are used to reduce parasitic oscillations, then electromagnetic compatibility is improved, but switching times are lengthened and switching losses increase
Solution Approach 1:
The patent employs feedback by detecting the actual oscillation amplitude of the output signal during each PWM clock period and using this information to dynamically adjust the control signal. The oscillation detector monitors the output signal, and the control unit modifies the control signal's amplitude or timing based on the detected oscillation characteristics, creating a closed-loop system that actively suppresses parasitic oscillations without the need for external passive components.
Solution Approach 2:
The patent changes the parameters of the control signal dynamically by adjusting its amplitude or timing based on detected oscillation conditions. Instead of using fixed external components, the control signal's characteristics are modified in real-time according to the oscillation state, allowing optimization of both oscillation suppression and switching performance without compromising switching speed.
2Object-affected harmful factors
If external capacitors, gate resistors, or suppressor circuits are used to reduce parasitic oscillations, then electromagnetic compatibility is improved, but manufacturing costs increase
Solution Approach 1:
The patent employs feedback by detecting the actual oscillation amplitude of the output signal during each PWM clock period and using this information to dynamically adjust the control signal. The oscillation detector monitors the output signal, and the control unit modifies the control signal's amplitude or timing based on the detected oscillation characteristics, creating a closed-loop system that actively suppresses parasitic oscillations without the need for external passive components.
Solution Approach 2:
The system performs self-service by using its own control signal and output signal to detect and suppress oscillations. The control device monitors its own operation through the oscillation detector and automatically adjusts the control signal to maintain optimal performance, eliminating the need for additional external suppression components and reducing manufacturing complexity.
3Speed
If high-speed electronic components are used to adapt output current or voltage to gate-source or drain-source voltages, then switching performance is improved, but costs increase
Solution Approach 1:
The patent applies dynamics by making the control signal adaptable and variable rather than fixed. The control signal's amplitude or timing is dynamically adjusted based on real-time oscillation detection, allowing the system to optimize switching performance for different operating conditions without requiring expensive high-speed components. This dynamic adaptation enables cost-effective achievement of high switching performance.
4Object-affected harmful factors
If gate resistors are used to reduce rates of change of gate current and voltage, then parasitic oscillations are reduced, but switching delays increase
Solution Approach 1:
The patent changes the parameters of the control signal dynamically by adjusting its amplitude or timing based on detected oscillation conditions. Instead of using fixed external components, the control signal's characteristics are modified in real-time according to the oscillation state, allowing optimization of both oscillation suppression and switching performance without compromising switching speed.
Data Source
AI summary
An electronic component is switched under the control of a pulse-width modulation signal. The electronic component outputs an output signal that is controlled by a control signal. The switching on or off is initiated within a pulse-width modulation cycle period at a level change time by a change of the pulse-width modulation signal. The control signal is set within each PWM cycle period to a first control value between the level change time and a first switching time, to a second control value between the first switching time and a second switching time, and to a third control value from the second switching time until a final gate-voltage value is reached on the gate of the electronic component. Each switching time of a PWM period is determined in dependence on an amplitude value determined during a preceding PWM cycle period, to limit amplitudes of the oscillation of the output signal.