Digital PWM Signal Generation Using FPGA Delay Elements
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Solution Overview
Problem
Existing methods for generating PWM signals in high-frequency applications are limited by resolution, leading to signal disturbances due to clock frequency constraints, and lack effective feedback correction mechanisms.
Innovation Solution
A method utilizing Field Programmable Gate Arrays (FPGAs) with IO Delay elements for generating fully digital, high-resolution PWM signals, incorporating feedback correction through proportional-integral-derivative controllers and analog-digital converters to adjust counter and tap values, ensuring high-frequency PWM generation without resolution reduction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If PWM signals are generated using traditional digital methods limited by clock frequency, then the generation process is simple, but the resolution is reduced and signal disturbances occur at high frequencies
Solution Approach 1:
The patent introduces a time delay dimension by inserting delay elements in the feedback path. This allows the system to achieve high resolution not through higher clock frequencies, but through precise temporal positioning of PWM edges relative to the triangular wave, effectively adding a time-based degree of freedom to the PWM generation process.
Solution Approach 2:
The patent implements a feedback mechanism where the actual PWM output is delayed and compared with the reference triangular wave. The phase difference detected through this feedback loop is used to dynamically adjust the PWM generation timing, enabling high resolution control that compensates for system variations and maintains precision at high frequencies.
2Speed
If high-frequency PWM signals are generated, then the switching speed improves, but the resolution is reduced leading to signal disturbances
Solution Approach 1:
The feedback loop continuously monitors the phase relationship between the PWM signal and the triangular wave. By detecting phase errors introduced at high frequencies and dynamically adjusting the PWM timing through delay elements, the system maintains high resolution precision even at elevated switching frequencies, eliminating the traditional trade-off between speed and precision.
Solution Approach 2:
The patent dynamically adjusts the delay parameter in the feedback path based on the operating frequency. By changing the delay value adaptively, the system optimizes the phase alignment between PWM edges and the triangular wave at each frequency point, ensuring high resolution is maintained across the entire frequency range without signal disturbances.
3Measurement precision
If feedback correction is implemented to improve resolution, then the signal quality improves, but the system complexity increases
Solution Approach 1:
The patent implements a feedback mechanism where the actual PWM output is delayed and compared with the reference triangular wave. The phase difference detected through this feedback loop is used to dynamically adjust the PWM generation timing, enabling high resolution control that compensates for system variations and maintains precision at high frequencies.
Solution Approach 2:
The delay element serves as an intermediary component in the feedback path. It provides the necessary temporal adjustment without requiring complex processing, acting as a simple yet effective mediator that enables high-resolution control by aligning the feedback signal phase with the reference waveform.
Data Source
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AI summary
The invention relates to a method for generating digital, high resolution pulse width modulation (PWM) signals and a digital feedback correction method suited to the method of generation intended for use in feed forward systems, feedback systems and combined feed forward and feedback systems.