Uniform Distribution Pulsewidth Modulation Strategy for Three-Phase Converters to Reduce Conducted EMI and Switching Loss
TL;DR: The cause of the EMI spikes for VSFPWM is investigated, and the analysis results show that the nonuniform distribution of switching frequency is the primary reason, and a novel PWM strategy called uniform distribution PWM (UDPWM) is proposed to eliminate the E MI spikes and to further reduce conducted EMI.
Abstract: It is necessary to suppress the emission level of conducted electromagnetic interference (EMI) for the power electronics converters, and the variable switching frequency pulsewidth modulation (VSFPWM) is an alternative approach to reduce conducted EMI without adding bulky passive components. However, the experimental results indicate that many obvious EMI spikes in spectrum remain so that the conducted EMI reduction for VSFPWM is limited. In order to eliminate the EMI spikes in spectrum, this article first investigates the cause of the EMI spikes for VSFPWM, and the analysis results show that the nonuniform distribution of switching frequency is the primary reason. Then, a novel PWM strategy called uniform distribution PWM (UDPWM) is proposed to eliminate the EMI spikes and to further reduce conducted EMI. The design of a UDPWM is based on the uniform distribution of switching frequency and the principle of less switching loss. Moreover, the analytical formula of switching frequency is also deduced in detail, which adopts fixed variation range of switching frequency whatever the modulation index is. Finally, the experiments are carried out to validate the effectiveness of the UDPWM in reducing conducted EMI and switching loss. The UDPWM can approximately reduce conducted EMI by 20 dB compared with the conventional constant switching frequency PWM, and all obvious spikes in the spectrum are eliminated compared with VSFPWM.
Citations
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TL;DR: A comprehensive review and comparison of different modeling approaches for conducted emissions are provided, which can be used as a design guideline for engineers to assist them with a more efficient and electromagnetically-compatible design.
Abstract: Electromagnetic interference issues are associated with high-speed switching of power converters. EMI modeling is an essential tool to study and control the EMI emission, enabling more efficient solutions. A comprehensive review and comparison of different modeling approaches for conducted emissions are provided in this paper, which can be used as a design guideline for engineers. For a motor drive application, common mode and differential mode conducted emissions are studied, and dominant noise production mechanisms are identified. Moreover, a review of various modeling techniques is presented for the main parasitic components of the system. Finally, time domain and frequency domain analysis approaches are explored along with the equivalent circuits which enable fast prediction of EMI emissions. This paper intends to help the reader develop an organized understanding of conducted emission modeling to assist them with a more efficient and electromagnetically-compatible design.
32 citations
Cites background from "Uniform Distribution Pulsewidth Mod..."
...• switching modulation schemes such as random, chaotic and variable frequency modulations: switching frequency spectrum is spread over a wide range of frequencies [84]–[86], • snubbers, soft-switching solutions and gate driver modifications [87]–[91]: EMI noise level is controlled by shaping the switching voltage and current, • component selection and circuit topology [92]–[94]: semiconductor technology and the circuit topology are optimized for emission reduction considering other design requirements....
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TL;DR: A family of spread-spectrum modulation strategies that can effectively reduce the conducted EMI for power electronics converters are proposed, which eliminate the noise spikes in conducted E MI spectrum, reducing the harsh requirements for designing EMI filters.
Abstract: Spread-spectrum modulation strategy is recognized as an effective solution to reduce conducted electromagnetic interference (EMI). This article proposes a family of spread-spectrum modulation strategies that can effectively reduce the conducted EMI for power electronics converters. The introduced modulation strategies eliminate the noise spikes in conducted EMI spectrum, reducing the harsh requirements for designing EMI filters. The proposed spread-spectrum methods are based on the distribution characteristic of switching frequency, which determine the waveform function of switching frequency. In addition, the design principles take reduced switching losses and fixed variation range of switching frequency into consideration. The differential equation that makes the switching frequency subject to arbitrary statistical distribution is derived in detail together with the corresponding solutions. Three typical statistical distributions represented by uniform distribution, exponential distribution and normal distribution are performed. Relevant experiments have verified that the proposed spread-spectrum modulation schemes can reduce the conducted EMI about 20 dB. Finally, several other typical spread-spectrum modulation schemes such as random pulsewidth modulation (PWM), periodic PWM, and programmed PWM are implemented in converters for comprehensive comparison to evaluate the proposed spread-spectrum modulation schemes.
18 citations
Cites background from "Uniform Distribution Pulsewidth Mod..."
...Periodic PWM changes the switching frequency periodically according to a certain law instead of being randomly changed [31]–[35]....
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TL;DR: In this paper , the authors proposed a spread-spectrum (SS) strategy, called space SS (SSS), to suppress the conducted EMI of a modular multilevel converter (MMC).
Abstract: A modular multilevel converter (MMC) is widely used due to its various advantages. However, it causes serious electromagnetic interference (EMI) problems. Therefore, it is necessary to suppress the conducted EMI of MMC. A novel spread-spectrum (SS) strategy, called space SS (SSS), is proposed in this article. The core idea of the SSS strategy is to make the carrier frequency of each submodule different. The principle and formula derivation of the SSS strategy are elaborated. SSS is a highly free strategy because carrier frequency can be distributed arbitrarily with space position. Several methods for determining carrier frequency distribution are proposed in this article. These methods not only achieve EMI suppression, but also take into account less circulating current, higher switching frequency, and lower switching loss. Total harmonic distortion (THD) and switching loss variation under the SSS strategy are also studied in the article. Experiments are carried out to validate the effectiveness of the SSS strategy. The SSS strategy can reduce the EMI by more than 12 dB and all obvious spikes in the spectrum are eliminated effectively. Besides, it is easy to implement and suitable for practical systems with quantities of submodules.
6 citations
28 Jun 2021
TL;DR: In this article, a modified Voltage Controlled-Virtual Synchronous Machine (VC-VISMA) controller is proposed aiming to control voltage and frequency even under black start, and the performance of this modified controller is validated in MATLAB/Simulink.
Abstract: Renewable Distributed Energy Resources (DERs) are on track to dominate in near future, mitigating the ever-growing energy demand. DERs mostly interact with the grid through power electronic converters, whereas traditional power grid’s power operations are controlled by Synchronous Machines (SMs). With more DERs coming into the picture and contributing an increasing portion of power flow, the power control architecture of the grid must be revisited. There are many benefits of using a Voltage Controlled-Virtual Synchronous Machine (VC-VISMA) controller, such as communication-less cooperation between power sources achieving tight regulation of grid voltage and frequency. But a major disadvantage of this controller is it cannot operate under conditions where the central grid is absent, such as black-start. In this paper, a modified VC-VISMA or Dropped VISMA (DVSM) is proposed aiming to control voltage and frequency even under black start. The performance of this modified controller is validated in MATLAB/Simulink.
4 citations
08 Jun 2020
TL;DR: Simulations proved that the delay compensation technique can be used to counteract the EMI increase due to the load parasitics, and an equivalent model is derived and verified by simulation.
Abstract: This paper analyzes the influence of the load parasitics on the conducted electromagnetic emissions, especially on their common mode component. The analyses have been performed on a BLDC motor driver, switched with bipolar PWM. According to the final installation of both the electronic module and the load, the prescribed test setup for the electromagnetic interference (EMI) measurements can vary. This modifies the parasitic element values and it can even worsen the emission level, when the load chassis is connected to the reference plane. In this paper, the effect of the load parasitic elements on the conducted emission is analyzed in details, and an equivalent model is derived and verified by simulation. Moreover, such simulations proved that the delay compensation technique can be used to counteract the EMI increase due to the load parasitics.
3 citations
References
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Book•
03 Oct 2003
TL;DR: In this paper, an integrated and comprehensive theory of PWM is presented and the selection of the best algorithm for optimum pulse width modulation is an important process that can result in improved converter efficiency, better load (motor) efficiency, and reduced electromagnetic interference.
Abstract: An integrated and comprehensive theory of PWM. The selection of the best algorithm for optimum pulse width modulation is an important process that can result in improved converter efficiency, better load (motor) efficiency, and reduced electromagnetic interference. However, the identification of the best approach is a complex process requiring extensive mathematical manipulation.
2,450 citations
"Uniform Distribution Pulsewidth Mod..." refers background in this paper
...Although PWM can achieve the fundamental frequency output voltage as expected through varying the duty cycle of the converter switches at a high switching frequency, the output trains of switched pulses also contain the affluent high-frequency harmonics [4], which can generate conducted electromagnetic interference (EMI) in the transmission lines....
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...The double Fourier series can accurately calculate the spectrum of CSFPWM, and the harmonic components of the pole output voltage are expressed as [4]...
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...quency PWM (CSFPWM) results in the harmonic energy mainly distributing near the carrier harmonics [4], which eventually manifests as the obvious EMI spikes in the spectrum because...
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TL;DR: This paper comprehensively analyzes the relationship between space-vector modulation and three-phase carrier-based pulse width modulation and shows that all the drawn conclusions are independent of the load type.
Abstract: This paper comprehensively analyzes the relationship between space-vector modulation and three-phase carrier-based pulse width modulation (PWM). The relationships involved, such as the relationship between modulation signals (including zero-sequence component and fundamental components) and space vectors, the relationship between the modulation signals and the space-vector sectors, the relationship between the switching pattern of space-vector modulation and the type of carrier, and the relationship between the distribution of zero vectors and different zero-sequence signal are systematically established. All the relationships provide a bidirectional bridge for the transformation between carrier-based PWM modulators and space-vector modulation modulators. It is shown that all the drawn conclusions are independent of the load type. Furthermore, the implementations of both space-vector modulation and carrier-based PWM in a closed-loop feedback converter are discussed.
1,004 citations
"Uniform Distribution Pulsewidth Mod..." refers methods in this paper
...sequence component into the three-phase balanced sinusoidal references to implement SVPWM equivalently [30], thereby reducing the calculation time....
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01 Jan 2015
TL;DR: An overview of the existing PV energy conversion systems, addressing the system configuration of different PV plants and the PV converter topologies that have found practical applications for grid-connected systems is presented in this paper.
Abstract: Photovoltaic (PV) energy has grown at an average annual rate of 60% in the last five years, surpassing one third of the cumulative wind energy installed capacity, and is quickly becoming an important part of the energy mix in some regions and power systems. This has been driven by a reduction in the cost of PV modules. This growth has also triggered the evolution of classic PV power converters from conventional singlephase grid-tied inverters to more complex topologies to increase efficiency, power extraction from the modules, and reliability without impacting the cost. This article presents an overview of the existing PV energy conversion systems, addressing the system configuration of different PV plants and the PV converter topologies that have found practical applications for grid-connected systems. In addition, the recent research and emerging PV converter technology are discussed, highlighting their possible advantages compared with the present technology. Solar PV energy conversion systems have had a huge growth from an accumulative total power equal to approximately 1.2 GW in 1992 to 136 GW in 2013 (36 GW during 2013) [1]. This phenomenon has been possible because of several factors all working together to push the PV energy to cope with one important position today (and potentially a fundamental position in the near future). Among these factors are the cost reduction and increase in efficiency of the PV modules, the search for alternative clean energy sources (not based on fossil fuels), increased environmental awareness, and favorable political regulations from local governments (establishing feed-in tariffs designed to accelerate investment in renewable energy technologies). It has become usual to see PV systems installed on the roofs of houses or PV farms next to the roads in the countryside. Grid-connected PV systems account for more than 99% of the PV installed capacity compared to
772 citations
TL;DR: An overview of the existing PV energy conversion systems, addressing the system configuration of different PV plants and the PV converter topologies that have found practical applications for grid-connected systems is presented in this article.
Abstract: Photovoltaic (PV) energy has grown at an average annual rate of 60% in the last five years, surpassing one third of the cumulative wind energy installed capacity, and is quickly becoming an important part of the energy mix in some regions and power systems. This has been driven by a reduction in the cost of PV modules. This growth has also triggered the evolution of classic PV power converters from conventional single-phase grid-tied inverters to more complex topologies to increase efficiency, power extraction from the modules, and reliability without impacting the cost. This article presents an overview of the existing PV energy conversion systems, addressing the system configuration of different PV plants and the PV converter topologies that have found practical applications for grid-connected systems. In addition, the recent research and emerging PV converter technology are discussed, highlighting their possible advantages compared with the present technology.
772 citations
"Uniform Distribution Pulsewidth Mod..." refers background in this paper
...generation, transportation traction, high-voltage direct current transmission, and so on [1]–[3]....
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TL;DR: In this paper, variable switching frequency control methods are proposed to satisfy different ripple requirements, which can improve the performance of EMI and efficiency without impairing the power quality of three-phase converters.
Abstract: Compared with the widely used constant switching frequency pulse-width-modulation (PWM) method, variable switching frequency PWM can benefit more because of the extra freedom Based on the analytical expression of current ripple of three-phase converters, variable switching frequency control methods are proposed to satisfy different ripple requirements Switching cycle $T_{s}$ is updated in DSP in every interruption period based on the ripple requirement Two methods are discussed in this paper The first method is designed to arrange the current ripple peak value within a certain value and can reduce the equivalent switching frequency and electromagnetic interference (EMI) noise; the second method is designed to keep ripple current RMS value constant and reduce the EMI noise Simulation and experimental results show that variable switching frequency control could improve the performance of EMI and efficiency without impairing the power quality
149 citations
"Uniform Distribution Pulsewidth Mod..." refers background or methods in this paper
...VSFPWM, which can spread the concentrated harmonic energy [23], is a good candidate to replace the CSFPWM scheme....
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...ing frequency according to the current ripple prediction model [23]....
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...Step two: The KVL equation for a single phase to solve the current ripple is calculated according to the equivalent circuit [23]....
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...domly varies the switching frequency so that the unpredictability of the current ripple is adverse to the design of the power electronic converters [20], [23]....
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