DC Load Power Control Using Fixed-Frequency Fixed-Duration Pulses
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Solution Overview
Problem
Conventional methods for controlling power to DC loads, such as Pulse Width Modulation (PWM) and Variable Frequency (VF), have operational shortcomings, including inaccuracies in power delivery and inefficiencies, particularly in applications requiring precise motor movements and fine control.
Innovation Solution
The use of control pulses with fixed frequency and fixed duration (FFFD) techniques, which involve generating a sequence of control pulses of fixed duration and frequency to vary the power supplied to electrical loads, allowing for precise control by adjusting the number of pulses within a repeating time cycle.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If Pulse Width Modulation (PWM) is used to control power to DC loads, then power control capability is provided, but precision and accuracy of power delivery deteriorates
Solution Approach 1:
The control method segments the power delivery into discrete fixed-duration pulses at fixed frequency, where the number of pulses within a time period determines the power level. This segmentation approach replaces continuous PWM duty cycle control with discrete pulse counting, improving measurement precision for power delivery while maintaining manageable system complexity through standardized pulse generation.
2Measurement precision
If Variable Frequency (VF) pulses are used to control power to DC loads, then power control capability is provided, but operational accuracy deteriorates
Solution Approach 1:
The invention merges the advantages of fixed-frequency stability with fixed-duration precision by combining both constraints in the FFFD pulse train. This merging eliminates the need to trade off between frequency variation and response speed, as both frequency and duration are held constant while power control is achieved through pulse number modulation, simultaneously improving accuracy and maintaining response speed.
3Object-affected harmful factors
If conventional PWM or VF methods are used, then power control is achieved, but radio frequency interference increases
Solution Approach 1:
The invention converts the potential harm of radio frequency interference by using fixed-frequency pulses that operate at predictable, stable frequencies rather than varying frequencies. This allows for better EMI filtering and shielding design, as the interference occurs at known frequencies that can be targeted by filters, thereby reducing overall RFI impact while maintaining control simplicity through the same pulse train generation approach.
Data Source
AI summary
Fixed Frequency, Fixed Duration power controls methods and systems are described for application of power to electrical loads. FFFD techniques according to the present disclosure utilize power train pulses with fixed-frequency fixed-duration pulses to control power applied to a load. The load can be any type of DC load. FFFD techniques allows for controlled variation of the fixed length of the ON pulse, the Fixed length of the OFF or recovery period, the total time period for one cycle, and/or the number of pulses in that time period. Applications to electric motors, electric lighting, and electric heating are described. Related circuits are also described.