Controlling systems with motor drives using pulse width modulation
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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 either require manual adjustment or increased material costs for dampening.
Innovation Solution
A system that uses a controller to select and operate an electronic power converter with a PWM algorithm that mitigates resonance frequencies by analyzing harmonic signatures and determining optimal PWM algorithms to minimize mechanical vibrations.
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 and switches between multiple PWM algorithms based on real-time vibration levels and resonance frequency detection. The controller monitors vibration sensors and adjusts the PWM algorithm selection during operation, making the power supply adaptive to changing system conditions rather than using a fixed algorithm.
Solution Approach 2:
The system changes key parameters of the PWM algorithm including switching frequency, pulse width, and harmonic injection patterns to avoid resonance frequencies. By modifying these parameters dynamically, the system maintains efficient power transfer while suppressing mechanical vibrations through frequency avoidance and active damping.
2Object-affected harmful factors
If manual adjustment or dampening materials are used to reduce vibrations, then mechanical vibrations are reduced, but device complexity and material costs increase
Solution Approach 1:
The system replaces passive mechanical dampening materials with an active electronic control system that uses sensor feedback and algorithmic adjustment. Instead of adding physical dampers, the system uses software-based vibration cancellation through dynamic PWM parameter adjustment, reducing material costs and simplifying the mechanical structure.
Solution Approach 2:
The system performs self-diagnosis and self-adjustment by monitoring its own vibration levels through integrated sensors and automatically selecting appropriate PWM algorithms without external intervention. This self-regulating capability eliminates the need for manual adjustment mechanisms and reduces overall system complexity.
3Device complexity
If a fixed PWM algorithm is used, then device complexity is reduced, but adaptability to resonance frequencies deteriorates
Solution Approach 1:
The system divides the control strategy into multiple discrete PWM algorithms, each optimized for specific frequency ranges and operating conditions. Instead of one complex adaptive algorithm, the system uses a library of simpler segmented algorithms that can be selectively applied based on detected resonance conditions, maintaining low individual algorithm complexity while achieving high overall adaptability.
Solution Approach 2:
The controller is designed with universal adaptability to handle multiple resonance scenarios by selecting from a family of PWM algorithms. Each algorithm serves multiple functions including power conversion, vibration suppression, and harmonic mitigation, allowing the system to adapt to various resonance frequencies without requiring dedicated solutions for each condition.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The solution effectively reduces mechanical vibrations by selecting a PWM algorithm that avoids resonance frequencies, thereby minimizing noise and damage, and allows for dynamic adjustment during the system's life cycle, improving operational efficiency and reducing material costs.
Implementation Method 1
Digital power supplies provide efficient power supply by using pulse-width modulation (PWM) to quickly switch on and off power, in order to provide the desired power at the one or more motor drives of the system
Implementation Method 2
The controller 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 HVAC and/or refrigeration system
Data Source
AI summary
A system includes an electronic power converter and a controller. The electronic power converter supplies power to one or more motor drives of an HVAC and/or refrigeration system. The controller obtains a plurality of pulse width modulation (PWM) algorithms. Each PWM algorithm has an associated harmonic signature. The controller further determines one or more resonance frequencies associated with the HVAC and/or refrigeration system. The controller 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 further operates the electronic power converter according to the first PWM algorithm.