A Feedback Quantizer based Pulse Width Modulation (FBQ-PWM) methodology applied to voltage source converters has been developed. The invention proposes a different and much simpler method to control switches of a converter (applicable for inverter or rectifiers, two level or multi-level, single phase or multi-phase) for the purpose of achieving Pulse Width Modulation (PWM). The new invention includes methodology of designing a digital feedback filter so that given undesired frequencies or frequency ranges are rejected in the converter switching noise without hardware filters. Compared to existing PWM technology, the new invention offers much simpler solution with additional capability (in harmonic noise shaping), thus corresponds to lower costs of product manufacturing, added quality of humming noise suppression and EMI mitigation, with extended range of converter applications.
Dr. Galina Mirzaeva, School of Electrical Engineering, University of Newcastle, Australia.
Prof Graham Goodwin, School of Electrical Engineering, University of Newcastle, Australia.
Australian Patent Application has been filed.
Features and Benefits
• A simple software solution
• Alternative to Space Vector Modulation with similar harmonic performance but lower implementation cost;
• Added feature of arbitrary noise shaping without costly hardware filters;
• Flexible setting, can be adapted to comply with given harmonic requirements or to avoid specified resonant frequencies;
• Low demand computational power and can be performed at fast frequency if needed;
• Simple implementation: calculations can be performed at constant frequency and in the same cycle as current sampling;
• Low switching losses: average switching frequency per device is 4 to 6 times lower than modulation frequency;
• Transparency to the rest of the control scheme: FBQ-PWM works with PI-, resonant or other standard current controllers;
• Distributed harmonic spectrum: with exemption of the specified ranges of rejection, harmonic energy is evenly distributed over the rest of the spectrum;
• Consequently, no acoustic noise or EMI issues: suitable for applications with space limitations and close to humans (EV, renewable energy converters, etc.);
• Also suitable for inverters of active front end rectifies; for two-level or multilevel converter topologies.
Market Value and Size
The inverter market is estimated to be $45 billion in 2012 and to reach $71 billion by 2020. A total of more than 28 million units were shipped in 2012 and estimated to grow to 80 million units in 2020.
There is potentially a large market for the invention. Firstly, this market includes conventional inverters and active front end rectifiers, two-level or multilevel, with an added benefit of noise shaping. Additional applications include medium and high voltage converters requiring low switching losses, as well as converters with stringent EMI and acoustic noise requirement (renewable energy converters, EV, aircrafts, etc.)
Potential Application and Market Opportunities
Some of the most attractive applications of this invention are: Solar PV, wind turbines, EV/HEV, electric train, induction furnace, motor drives and UPS.
This invention can provide cost savings in capital spending and maintenance, alongside with improved quality of performance.
The new technology has been proven at laboratory scale and now requires scale-up for commercial application.