PWM Algorithm Selection for HVAC Motor Drive Resonance Mitigation
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Solution Overview
Problem
Existing PWM methods in HVAC and refrigeration systems cause significant mechanical vibrations due to resonance frequencies, leading to noise and potential damage, and existing solutions fail to account for or adjust these vibrations effectively.
Innovation Solution
A system and method that use an electronic power converter and a controller to select a PWM algorithm based on the harmonic signature of the system, determining and mitigating resonance frequencies associated with the HVAC and/or refrigeration system to minimize mechanical vibrations by avoiding frequency overlaps.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If PWM is used to supply power efficiently, then power efficiency is improved, but mechanical vibrations increase due to resonance frequencies
Solution Approach 1:
The system dynamically selects PWM algorithms from a plurality of available algorithms based on real-time or predetermined resonance frequency characteristics of the HVAC system. The controller adapts the PWM switching pattern by choosing algorithms with harmonic signatures that avoid resonant frequencies, thereby maintaining power efficiency while minimizing mechanical vibrations.
Solution Approach 2:
The invention changes the parameters of the PWM algorithm selection by evaluating harmonic signatures against known resonance frequencies. Different PWM algorithms have different switching frequencies and harmonic content; by selecting algorithms whose harmonic signatures do not overlap with system resonance frequencies, the system maintains efficient power delivery while avoiding vibrational resonance.
2Device complexity
If PWM algorithms are selected without considering resonance frequencies, then device complexity is reduced, but mechanical vibrations and noise increase
Solution Approach 1:
The system performs preliminary analysis by obtaining resonance frequency characteristics of the HVAC system beforehand (either through measurement or predetermined data). This preliminary information is stored and used to guide the selection of PWM algorithms, allowing the controller to make informed decisions without complex real-time analysis during operation.
Solution Approach 2:
The invention uses harmonic signatures as simplified representations or copies of the complex PWM algorithm behaviors. Instead of analyzing entire PWM waveforms in real-time, the system compares compact harmonic signature profiles against resonance frequencies, reducing computational complexity while maintaining effective vibration mitigation.
3Device complexity
If a single PWM algorithm is used, then device complexity is minimized, but adaptability to different resonance conditions is reduced
Solution Approach 1:
The controller is designed with multi-functionality to handle multiple PWM algorithms within a single control system. The controller can select from a plurality of PWM algorithms based on the specific resonance conditions detected, making the system adaptable to different HVAC configurations, operating conditions, and resonance characteristics without requiring separate control systems.
Data Source
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AI summary
A system includes an electronic power converter (105) and a controller (115). The electronic power converter (105) supplies power to one or more motor drives of an HVAC and/or refrigeration system (110). The controller (115) obtains a plurality of pulse width modulation (PWM) algorithms. Each PWM algorithm has an associated harmonic signature. The controller (115) further determines one or more resonance frequencies associated with the HVAC and/or refrigeration system (110). The controller (115) also selects a first PWM algorithm from the plurality of PWM algorithms based at least in part on the harmonic signature associated with the first PWM algorithm mitigating the one or more resonance frequencies associated with the refrigeration system. The controller (115) further operates the electronic power converter (105) according to the first PWM algorithm.