Dual Battery PWM Controller Phase Shift Noise Reduction
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing power supply systems using two batteries and pulse width modulation control signals for voltage conversion experience significant noise due to electromagnetic interference, which has not been adequately addressed in previous studies.
Innovation Solution
A power supply system with a controller that adjusts the phases and frequencies of pulse width modulation control signals for two batteries, ensuring that high-level periods do not overlap and increasing the frequency of the control signals beyond human audible range to reduce noise.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If the carrier frequency of pulse width modulation control signals is raised beyond human audible range to reduce noise, then noise reduction is achieved, but switching loss increases and control complexity increases
Solution Approach 1:
The patent applies parameter changes by dynamically adjusting the carrier frequency of PWM control signals based on operating conditions. The controller varies the frequency within a range that keeps electromagnetic sound beyond human audible range (typically above 20kHz) while optimizing switching loss. This resolves the contradiction by making frequency adjustable rather than fixed, allowing the system to maintain noise reduction while minimizing energy loss at different power levels.
Solution Approach 2:
The patent implements dynamics by making the carrier frequency adaptive and variable rather than static. The control system continuously monitors operating conditions and adjusts the PWM frequency dynamically. This allows the system to respond to changing loads and maintain optimal performance, resolving the contradiction between noise reduction and switching loss by adapting frequency to actual operating requirements.
2Object-affected harmful factors
If the carrier frequency of pulse width modulation control signals is raised beyond human audible range to reduce noise, then noise reduction is achieved, but control complexity increases
Solution Approach 1:
The patent uses parameter changes by implementing variable carrier frequency control where the PWM frequency is adjusted as a controllable parameter. The controller modifies frequency settings based on operating conditions while maintaining the constraint that frequency remains beyond human audible range. This approach achieves noise reduction without requiring overly complex control mechanisms, as frequency adjustment is a straightforward parameter modification.
3Productivity
If two pulse width modulation control signals are used for voltage conversion control of two batteries, then voltage conversion efficiency is improved, but electromagnetic noise increases
Solution Approach 1:
The patent applies periodic action by using two PWM control signals with different carrier frequencies for controlling the two batteries. By staggering the frequency periods, the electromagnetic noise from each converter operates at different frequencies, preventing constructive interference and reducing overall noise levels. This allows dual-battery voltage conversion to maintain high efficiency while minimizing electromagnetic interference through frequency diversification.
Solution Approach 2:
The patent implements parameter changes by assigning different carrier frequencies to the two PWM control signals. This frequency differentiation is a parameter modification that allows both converters to operate efficiently simultaneously while their electromagnetic emissions occur at different frequencies, thereby reducing overall noise. The parameter change (frequency assignment) resolves the contradiction between maintaining high conversion efficiency and reducing electromagnetic noise.
Data Source
AI summary
A power supply system includes: a first battery; a second battery; a voltage converter including a plurality of switching elements; and a controller configured to turn on or off the plurality of switching elements in accordance with pulse width modulation control. The controller is configured to control phases of the pulse width modulation control signals such that the first high-level period of the first pulse width modulation control signal and the second high-level period of the second pulse width modulation control signal do not overlap with each other at a predetermined condition.