Last updated on Jun 30, 2024

How do you reduce the common-mode voltage and the EMI noise in PWM converters using space vector modulation?

Pulse width modulation (PWM) converters are widely used in power electronics applications, such as motor drives, renewable energy systems, and power supplies. However, PWM converters also generate common-mode voltage (CMV) and electromagnetic interference (EMI) noise, which can affect the performance and reliability of the converter and the load. How do you reduce the CMV and the EMI noise in PWM converters using space vector modulation (SVM)?

Key takeaways from this article

Optimized switching sequences:

Space Vector Modulation (SVM) can minimize common-mode voltage (CMV) and electromagnetic interference (EMI) by using specific switching sequences. This technique requires understanding your system's impedance and selecting the right vectors to reduce noise.
Stay updated on trends:

To combat CMV and EMI in PWM converters, keep abreast of new SVM strategies and research. Continuous learning helps you apply the latest advancements to maintain optimal performance.

This summary is powered by AI and these experts

1 What is SVM?

SVM is a technique that controls the switching of the power devices in a PWM converter based on the position and magnitude of the reference voltage vector. SVM can generate different switching patterns or sequences, which can influence the CMV and the EMI noise of the converter. SVM can also achieve higher voltage utilization and lower harmonic distortion than conventional PWM methods.

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Johannes Buedel

Electric Energy Storage & Drive Systems | Research Associate @TH Aschaffenburg | Home Barista ☕
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Eine der Herausforderungen bei der Anwendung von SVM in PWM-Wandlern besteht darin, die richtige Balance zwischen der Reduzierung von CMV und EMI-Rauschen und der Aufrechterhaltung einer hohen Spannungsausnutzung und geringen harmonischen Verzerrung zu finden. Zukünftige Trends könnten die Entwicklung von fortgeschrittenen Modulationstechniken umfassen, die eine noch effizientere Rauschunterdrückung ermöglichen.

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Sneha Narasimhan

PhD Candidate | Graduate Research Assistant | VP - Student Leadership Council at FREEDM Systems Center | LinkedIn - Top Electrical Engineering Voice
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Space Vector Modulation (SVM) is a technique used to control the switching of power devices in a Pulse Width Modulation (PWM) converter based on the position and magnitude of the reference voltage or current vector. Additionally, adjusting the switching pattern can impact common-mode emissions and the switching loss of the power converter.

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Waleed Sahhary

Chief Executive Officer at BWS e-Mobility Technologies GmbH, Specialist in Artificial Intelligence Basesd Electric Power Train Design, Instructor at hdt (Haus der Technik), and E-Tech Academy.
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Es gibt mehrere Möglichkeiten, die Gleichtaktstörung zu unterdrücken bzw. zu reduzieren. Bei Injektion von einem Zero-Sequence-Vector, der eine Gegenspannung darstellt, die zum Eleminieren der Störung beiträgt. Bei SVPWM werden nicht die Standard aktiven Vektoren ausgewählt, wie z.B. 0,7,1 and 2 im Sektor 1, sondern es wedren Vektoren von benachbarten Sektoren ausgewählt, die mathematisch die gleiche geometrische Summe ergeben, allerdings deren resultierende Spannung zum UNterdrucken der Gleichtaktspannung führt.

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2 How does SVM affect CMV?

CMV is the voltage difference between the converter output terminals and the ground. CMV can cause bearing currents, insulation degradation, and common-mode currents in the load. The CMV of a PWM converter depends on the switching state of the power devices and the parasitic capacitances of the converter and the load. SVM can reduce the CMV by minimizing the switching state changes and selecting the switching sequences that have zero or low CMV levels.

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Johannes Buedel

Electric Energy Storage & Drive Systems | Research Associate @TH Aschaffenburg | Home Barista ☕
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In einem ideal isolierten System führt die Gleichtaktspannung zu keinem Stromfluss. Allerdings gibt es in der Praxis kapazitive Umladeströme, die durch die Isolation der Wicklung oder die Lager der verbundenen elektrischen Maschine entstehen. Um die tatsächliche Belastung zu analysieren, müssen die Impedanzverhältnisse des gesamten Systems berücksichtigt werden. Die Raumzeigermodulation (SVM) bietet insbesondere bei Mehrpunktwechselrichtern die Möglichkeit, durch die Auswahl spezifischer Schaltvektoren die Gleichtaktbelastung zu minimieren.

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Waleed Sahhary

Chief Executive Officer at BWS e-Mobility Technologies GmbH, Specialist in Artificial Intelligence Basesd Electric Power Train Design, Instructor at hdt (Haus der Technik), and E-Tech Academy.
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indem man einen Zero-Vector einführt, dessen Frequenz und Amplitude zur Unterdrucken der Gelichtaktspannung beiträgt. Dies kann in Abhängigkeit vom aktuellen Sektor und Schaltmuster erfolgen.

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3 How does SVM affect EMI noise?

EMI noise is the unwanted electromagnetic radiation that can interfere with other devices or circuits. EMI noise can be classified into differential-mode noise and common-mode noise, depending on the source and the path of the noise. The differential-mode noise is mainly caused by the high-frequency switching of the power devices and the parasitic inductances of the converter and the load. The common-mode noise is mainly caused by the CMV and the parasitic capacitances of the converter and the load. SVM can reduce the EMI noise by minimizing the switching frequency and the rate of change of voltage and current, and by selecting the switching sequences that have low common-mode noise levels.

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4 How do you choose the optimal SVM switching sequence?

The optimal SVM switching sequence is the one that minimizes the CMV and the EMI noise while maintaining the desired output voltage and current. There are different criteria and methods to choose the optimal SVM switching sequence, such as minimizing the switching state changes, minimizing the switching frequency, minimizing the common-mode current, minimizing the EMI spectrum, or optimizing a multi-objective function. The choice of the optimal SVM switching sequence may also depend on the type and topology of the PWM converter, such as two-level, three-level, or multilevel converters.

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Waleed Sahhary

Chief Executive Officer at BWS e-Mobility Technologies GmbH, Specialist in Artificial Intelligence Basesd Electric Power Train Design, Instructor at hdt (Haus der Technik), and E-Tech Academy.
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Die Schaltreinfolge kann je nach Optimierungsziel anderes ausgewählt werden: z.B. wenn die Schaltverluste minimiert werden sollen, dann wird die Schaltreinfolge so ausgewählt, dass minimale Schaltvorgänge stattfinden, das wird erreicht, in dem pro Schaltvorgang nur ein Schalter umgeschaltet wird. Sollte der Fokus auf die gleichmäßige Verteilung von Verlusten auf alle Haalbleiter-Schalter sein, dann wedren solche Schaltvorgänge wie DSVPWM mit kontineurlichen oder split PWM ausgewählt

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5 What are some examples of SVM switching sequences?

There are many types of SVM switching sequences, such as active vector, zero vector, adjacent vector, non-adjacent vector, discontinuous vector, or continuous vector sequences. Each type of SVM switching sequence has different advantages and disadvantages in terms of CMV and EMI noise reduction. For example, active vector sequences use only the active voltage vectors to generate the output voltage, which can achieve high voltage utilization and low harmonic distortion, but also high CMV and EMI noise levels. Zero vector sequences use only the zero voltage vectors to generate the output voltage, which can achieve low CMV and EMI noise levels, but also low voltage utilization and high harmonic distortion.

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6 What are some challenges and future trends of SVM for PWM converters?

SVM is a powerful and flexible technique that can reduce the CMV and the EMI noise of PWM converters, but it also poses some challenges and opportunities for further research and development. Some of the challenges include the complexity and computation cost of selecting and implementing the optimal SVM switching sequence, the trade-off between CMV and EMI noise reduction and other performance parameters, such as efficiency, power quality, and thermal stress, and the compatibility and robustness of SVM with different converter topologies, control methods, and load characteristics. Some of the future trends include the development of new SVM algorithms and strategies that can adapt to different operating conditions and objectives, the integration of SVM with advanced modulation methods, such as pulse density modulation or random pulse width modulation, and the application of SVM to emerging converter technologies, such as wide bandgap devices or modular converters.

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Sneha Narasimhan

PhD Candidate | Graduate Research Assistant | VP - Student Leadership Council at FREEDM Systems Center | LinkedIn - Top Electrical Engineering Voice
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Staying informed through technical platforms and research publications, professionals can keep up with these challenges and trends, driving advancements in SVM for PWM converters.

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7 Here’s what else to consider

This is a space to share examples, stories, or insights that don’t fit into any of the previous sections. What else would you like to add?

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How do you reduce the common-mode voltage and the EMI noise in PWM converters using space vector modulation?

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1 What is SVM?

2 How does SVM affect CMV?

3 How does SVM affect EMI noise?

4 How do you choose the optimal SVM switching sequence?

5 What are some examples of SVM switching sequences?

6 What are some challenges and future trends of SVM for PWM converters?

7 Here’s what else to consider

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