Open-Delta H-Bridge PWM Selection for Harmonic and Ripple Reduction
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Solution Overview
Problem
Existing H-bridge control methods for AC permanent magnet machines fail to minimize harmonic content and ripple current effectively, leading to increased heating due to the conventional selection of unipolar or bipolar PWM based solely on current waveform signs, resulting in additional harmonics and inefficiencies.
Innovation Solution
A predictive method and system that determines the optimal polarity and type of pulse width modulation (PWM) for H-bridge drivers by using machine temperature measurements, operation conditions, and dynamic winding models, employing a predictive duty cycle algorithm to select between unipolar and bipolar PWM based on back EMF, reference current, phase resistance, winding temperature, and supply voltage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If conventional PWM selection based on current waveform signs is used, then control simplicity is maintained, but harmonic content and ripple current increase
Solution Approach 1:
The patent changes the selection parameter from simple current waveform sign to a comprehensive evaluation of machine parameters including temperature measurements, operation conditions, and dynamic winding models. This parameter change enables optimal PWM type and polarity selection that minimizes harmonic content and ripple current while maintaining controlled complexity through systematic decision-making.
Solution Approach 2:
The patent implements feedback by using real-time temperature measurements and machine parameter monitoring to dynamically select PWM type and polarity. The system continuously evaluates current waveform characteristics, machine temperature, and operational conditions to adaptively choose the optimal PWM strategy, thereby reducing harmonic content and ripple current through closed-loop control.
2Ease of operation
If conventional PWM selection based on current waveform signs is used, then control simplicity is maintained, but ripple current increases
Solution Approach 1:
The patent changes the selection parameter from simple current waveform sign to a comprehensive evaluation of machine parameters including temperature measurements, operation conditions, and dynamic winding models. This parameter change enables optimal PWM type and polarity selection that minimizes ripple current while maintaining controlled complexity through systematic decision-making.
Solution Approach 2:
The patent implements feedback by using real-time temperature measurements and machine parameter monitoring to dynamically select PWM type and polarity. The system continuously evaluates current waveform characteristics, machine temperature, and operational conditions to adaptively choose the optimal PWM strategy, thereby reducing ripple current through closed-loop control.
3Object-generated harmful factors
If optimal PWM selection using machine parameters is implemented, then harmonic content and ripple current are reduced, but control complexity increases
Solution Approach 1:
The patent applies preliminary action by pre-characterizing the machine with temperature measurements and dynamic winding models during manufacturing or initial operation. These pre-acquired parameters are stored and used during normal operation to guide PWM selection, eliminating the need for complex real-time calculations while achieving optimal harmonic reduction and ripple current minimization.
Solution Approach 2:
The patent changes the selection parameter from simple current waveform sign to a comprehensive evaluation of machine parameters including temperature measurements, operation conditions, and dynamic winding models. This parameter change enables optimal PWM type and polarity selection that minimizes harmonic content and ripple current while maintaining controlled complexity through systematic decision-making.
4Loss of energy
If optimal PWM selection using machine parameters is implemented, then heating is reduced, but control complexity increases
Solution Approach 1:
The patent applies preliminary action by pre-characterizing the machine with temperature measurements and dynamic winding models during manufacturing or initial operation. These pre-acquired parameters are stored and used during normal operation to guide PWM selection, eliminating the need for complex real-time calculations while achieving optimal harmonic reduction and ripple current minimization.
Solution Approach 2:
The patent implements feedback by using real-time temperature measurements and machine parameter monitoring to dynamically select PWM type and polarity. The system continuously evaluates current waveform characteristics, machine temperature, and operational conditions to adaptively choose the optimal PWM strategy, thereby reducing heating through closed-loop control.
Data Source
AI summary
Embodiments of the present method and system permit an effective method for determining the optimum selection of pulse width modulation polarity and type including determining machine parameters, inputting the machine parameters into a predicted duty cycle module, determining the optimum polarity of the pulse width modulation for a predicted duty cycle based on a pulse width modulation generation algorithm, and determining the optimum type of the pulse width modulation for a predicted duty cycle based on the pulse width modulation generation algorithm.