Conducted Emission in an 85 kHz, 50 kW WPT System with Opposite-Phase Transfer and Spread Spectrum

Suzuki, Masatoshi; Ogawa, Kensuke; Shijo, Tetsu; Kanekivo, Yasuhiro; Inoue, K.; Ogura, Koji; Obayashi, Shuichi; Ishida, M.

doi:10.1109/wow45936.2019.9030666

Cited by 7 publications

(5 citation statements)

References 18 publications

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“…In order to reduce size and cost of the passive filters or even eliminate them, an interesting and useful approach called the spread spectrum was adapted from communication engineering and applied to conventional switch-mode power converters last decade [10]. Recently, the approach was also applied to inductive-resonant wireless battery chargers for reducing conducted and radiated emissions [11][12][13][14][15][16]. Spreading the spectrum of the conducted emissions of the wireless chargers can be achieved by different approaches, such as switching frequency modulation [5,13,16], simultaneous switching frequency and duty cycle modulation (also known as the hybrid modulation) [11], multi-switching frequency technique [12] or even multi-frequency-multi-duty-cycle approach [15].…”

Section: Introductionmentioning

confidence: 99%

Thorough Study of Multi-Switching-Frequency-Based Spread-Spectrum Technique for Suppression of Conducted Emissions from Wireless Battery Chargers

2023

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The multi-switching-frequency technique is one of the spread-spectrum techniques for suppression of conducted emissions generated by wireless battery chargers. Its advantage is a relatively easy implementation with a microcontroller. In this paper, an original thorough experimental study of the effect of the multi-switching-frequency-based spread spectrum technique parameters (e.g., combinations of number of pulses, frequency order, etc.) on the performance characteristics (conducted emissions levels, efficiency, etc.) of an inductive-resonant wireless battery charger with a closed loop control is presented. It is shown that combinations of a number of pulses and frequency order have a noticeable impact on the performance characteristics of the wireless chargers. The suppression of the conducted emissions can be improved significantly by using optimized parameters of the technique. Moreover, it is proved experimentally that a relatively inexpensive microcontroller with a transceiver can be used to implement both closed-loop control of the wireless charger and the multi-switching-frequency technique.

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Section: Introductionmentioning

confidence: 99%

Thorough Study of Multi-Switching-Frequency-Based Spread-Spectrum Technique for Suppression of Conducted Emissions from Wireless Battery Chargers

2023

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“…When designing a wireless battery charger, electromagnetic compatibility (EMC) issues should also be considered, because they are significant sources of conducted and radiated electromagnetic interference (EMI) to sensitive electronic devices [5][6][7][8][9][10], as is depicted in Figure 1a. Therefore, different national or international EMC standards specify the limits and measurement methods of EMI of the wireless battery chargers.…”

Section: Introductionmentioning

confidence: 99%

“…Although less effective (in terms of EMI suppression), the spread-spectrum approach has gained substantial popularity over the last two decades because it can be used for suppressing conducted and radiated EMI simultaneously and can be implemented by using a suitable program code for a microcontroller. The spread-spectrum technique was initially used for the suppression of EMI from traditional switching power converters [11,12], and recently, it was applied to inductive-resonant WPT systems (including wireless battery chargers) [5,[7][8][9]. Several types of the spread-spectrum technique exist for EMI reduction from wireless battery chargers, but the multi-switching frequency technique is preferable to other spread-spectrum techniques for wireless battery chargers because it can be implemented by using a relatively inexpensive microcontroller that can be used simultaneously for implementing constant current (CC) or constant voltage (CV) battery charging modes [9].…”

Section: Introductionmentioning

confidence: 99%

Wireless Battery Chargers Operating at Multiple Switching Frequencies with Improved Performance

et al. 2023

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The operation of wireless battery chargers at multiple switching frequencies may lead to a noticeable suppression of conducted and radiated electromagnetic interference (EMI) at the cost of decreased efficiency (mainly at lower load resistances) and increased peak and root mean square values of currents of power components of the wireless battery charger. Moreover, the reduction in conducted EMI is only moderate (<8.3 dB). Therefore, a novel approach based on modified resonant circuits and a modified control technique to obtain better reduction in the conducted and radiated EMI without significantly compromising other performance characteristics of the wireless battery charger is proposed and validated by using simulations and experiments. It is shown in this paper that the wireless charger operating at multiple switching frequencies with the proposed approach for the performance improvement has a more effective implementation of the four-switching frequency spread-spectrum technique with better conducted and radiated EMI reduction at all load resistances, lower values of peak and RMS currents at all load resistances, and higher efficiency in constant current mode and in the beginning of constant voltage mode (at lower values of the load resistances) than that of the conventional wireless charger operating at multiple switching frequencies.

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“…As a traditional way for conducted EMI reduction-input EMI filtering-adds noticeable cost, size and weight to the inductive-resonant WPT system, a spread-spectrum technique based on modulation of WPT system inverter switching frequency has been applied to inductive-resonant WPT systems [16][17][18][19][20][21][22]. A typical approach for the reduction of radiated emissions is shielding, but shields are expensive and they increase the size and cost of the WPT systems.…”

Section: Introductionmentioning

confidence: 99%

“…There are many papers related to the reduction of conducted emissions using a spread-spectrum approach in WPT systems [16][17][18][19]21,22], but there is only one paper [20] about the suppression of radiated emissions using the approach in WPT systems. As shown in [20], fundamental components of the radiated emissions of the inductive-resonant WPT system can be reduced by up to 8.3 dB when the spread-spectrum technique based on the random modulation of inverter-switching frequency is used.…”

Section: Introductionmentioning

confidence: 99%

Suppression of Radiated Emissions from Inductive-Resonant Wireless Power Transfer Systems by Using Spread-Spectrum Technique

et al. 2022

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Inductive-resonant wireless power transfer systems are often used for wireless transfer of electric power. However, they are significant sources of radiated electromagnetic emissions. The effect of spread-spectrum approach based on classical switching frequency modulation of inductive-resonant wireless power transfer system inverter operating frequency and multi-frequency technique on the radiated emissions and efficiency is studied experimentally in detail. The influence of the classical frequency modulation and multi-frequency technique parameters on the peak radiated emission levels and the efficiency of the inductive-resonant wireless power transfer system are investigated more comprehensively. It is shown in the paper that the spread-spectrum approaches can lead to an appreciable radiated emissions reduction with small or large impact on the system’s efficiency. Some useful recommendations on how to choose parameters of the periodic switching frequency modulation or the multi-frequency technique considering a trade-off between the radiated emissions reduction and the efficiency are also proposed.

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Conducted Emission in an 85 kHz, 50 kW WPT System with Opposite-Phase Transfer and Spread Spectrum

Cited by 7 publications

References 18 publications

Thorough Study of Multi-Switching-Frequency-Based Spread-Spectrum Technique for Suppression of Conducted Emissions from Wireless Battery Chargers

Thorough Study of Multi-Switching-Frequency-Based Spread-Spectrum Technique for Suppression of Conducted Emissions from Wireless Battery Chargers

Wireless Battery Chargers Operating at Multiple Switching Frequencies with Improved Performance

Suppression of Radiated Emissions from Inductive-Resonant Wireless Power Transfer Systems by Using Spread-Spectrum Technique

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