Multi-Phase PWM Frequency Transition With Continuous Phase Alignment
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Solution Overview
Problem
Existing pulse width modulation (PWM) technologies experience discontinuities and errors during frequency changes, leading to adverse effects such as overvoltage and oversaturation in circuits, due to improper phase shifts and threshold adjustments.
Innovation Solution
Implementing a method where a slave control counter extends its cycle during frequency transitions to align with the new phase delay count, using equations to calculate transitional cycles that avoid discontinuities and ensure proper edge threshold triggering, thereby maintaining a stable PWM waveform.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If frequency changes are implemented in PWM control, then adaptability to different operating conditions is improved, but discontinuities and errors occur in PWM waveforms
Solution Approach 1:
The patent applies preliminary action by calculating and setting the transitional maximum count before the frequency change occurs. The slave control counter is prepared with the appropriate transitional cycle parameters in advance, ensuring that when the frequency transition happens, the counter seamlessly aligns with the new phase delay count without causing discontinuities or errors in the PWM waveform.
2Measurement precision
If phase shifts are adjusted during frequency transitions, then multi-phase control accuracy is improved, but discontinuities occur in the control signal
Solution Approach 1:
The patent applies parameter changes by dynamically adjusting the maximum count parameter of the slave control counter during frequency transitions. By changing this parameter to a calculated transitional maximum count, the system achieves accurate phase shifts while maintaining control signal continuity, as the transitional cycle ensures the slave counter aligns properly with the new frequency and phase delay requirements.
3Device complexity
If standard PWM control is used, then circuit simplicity is maintained, but overvoltage and oversaturation occur during transitions
Solution Approach 1:
The patent applies preliminary action by pre-calculating the transitional maximum count using the formula Tcn=Tc−(Φdc−Φdn) before frequency transitions occur. This preparatory calculation ensures that when the slave control counter executes the transitional cycle, it seamlessly adjusts to the new frequency and phase delay, preventing the discontinuities that would otherwise cause overvoltage and oversaturation in the power circuit, all while maintaining relatively simple control circuitry.
Data Source
AI summary
In described examples, a method of generating a pulse width modulation (PWM) signal includes repeatedly master control counting, by a master control counter generator, which includes one or both of incrementing and decrementing a master control counter with a minimum value and a maximum value, and repeatedly slave control counting with a phase delay with respect to the master control counting, and during a transition period, slave control counting to a new maximum value or a new phase delay. A maximum count of the transition period is selected to result in the transition period reaching the minimum value at the new phase delay count. The PWM signal is generated by generating rising edges when the slave control counter reaches a rising edge threshold, and generating falling edges when the slave control counter reaches a falling edge threshold.