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2022 | Buch

Second Harmonic Current Reduction Techniques for Single-Phase Power Electronics Converter Systems

verfasst von: Prof. Xinbo Ruan, Dr. Li Zhang, Dr. Xinze Huang, Fei Liu, Prof. Guoping Zhu, Prof. Shiqi Kan

Verlag: Springer Nature Singapore

Buchreihe: CPSS Power Electronics Series

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Two-stage single-phase converters, including two-stage single-phase dc-ac inverters and two-stage single-phase PFC converters, are interfacing power converters between dc and ac voltage/current sources, which have been widely applied for dc-ac and ac-dc power conversion. For the two-stage single-phase converter, the ac-side power pulsates at twice the ac voltage frequency, resulting in second harmonic current (SHC) which might flow into the dc-dc converter, the dc voltage source, and dc load. This book clarifies the generation, propagation, and side-effects of this SHC and proposes the SHC reduction control schemes for the dc-dc converter, with different topologies and/or different operating modes, in the single-phase converter. On this basis, the second harmonic current compensator (SHCC) is proposed to compensate the SHC, significantly reducing the dc bus capacitance. In doing so, the electrolytic capacitors, with short lifetimes, are removed from the two-stage single-phase converter, leading to extended system lifetime and enhanced system stability. For having flawless SHC compensation performance, the port-current control schemes are proposed for the SHCC. Additionally, the stability analysis is carried out for the two-stage single-phase converter with the addition of SHCC. This book is a monograph combining theoretical analysis and engineering design, which could not only be a reference book for master students, Ph.D. students, and teachers majoring in power electronics but also be a handbook for the electrical engineers working on the research and development of LED drivers, EV on-board chargers, railway auxiliary power supplies, aviation power supplies, renewable energy generation systems, etc.

Inhaltsverzeichnis

Frontmatter
Chapter 1. Introduction
Abstract
Two-stage single-phase converters, including the two-stage single-phase dc-ac inverters and two-stage single-phase power factor correction (PFC) converters, are the power conversion interface between the ac port and dc port, which have been widely applied in various power conversion applications. For the two-stage single-phase converters, the instantaneous power at the ac port pulsates at twice the ac voltage frequency (2fac), generating the second harmonic current (SHC) at the intermediate dc bus. In this chapter, the generation and propagation mechanism of the SHC are revealed. Then, the negative effects of the SHC on the dc-dc converter, dc source and dc load are illustrated. Finally, three kinds of SHC reduction methods, including the passive-components-based methods, closed-loop-control methods of the dc-dc converter, and power-decoupling methods, are reviewed comprehensively.
Xinbo Ruan, Li Zhang, Xinze Huang, Fei Liu, Guoping Zhu, Shiqi Kan
Chapter 2. Basic Approaches for Reducing Second Harmonic Current in Two-Stage Single-Phase Converters
Abstract
This chapter studies the basic approaches for reducing the second harmonic current (SHC) in the two-stage single-phase converter from the dc-bus port-impedance perspective. The dc-dc converters in two-stage single-phase converters are categorized into two types, namely, bus-voltage-controlled converter (BVCC) and bus-current controlled converter (BCCC). The dc-bus port impedances of the BVCC and the BCCC are derived. Based on the dc-bus port-impedance characteristics, advanced control schemes are expected to increase the dc-bus port-impedance for reducing the SHC in the BVCC, whereas the dc bus voltage ripple should be limited for reducing the SHC in the BCCC. Targeted at the practical applications where the use of electrolytic capacitors must be prohibited, the electrolytic capacitor-less second harmonic current compensator (SHCC) is further presented to replace the electrolytic capacitors to serve as the dc bus capacitor. Doing so removes the electrolytic capacitors in the two-stage single-phase converters, and therefore benefits the two-stage single-phase converter with enhanced reliability and extended lifetime.
Xinbo Ruan, Li Zhang, Xinze Huang, Fei Liu, Guoping Zhu, Shiqi Kan
Chapter 3. Second Harmonic Current Reduction for Two-Stage Single-Phase Inverter with Buck-Derived Front-End Bus-Voltage-Controlled Converter
Abstract
This chapter studies the second harmonic current (SHC) reduction for the two-stage single-phase inverter with buck-derived front-end bus-voltage-controlled converter (BVCC). The mechanism for the SHC propagation is revealed, indicating that the buck-derived BVCC and the input dc voltage source would be free of the SHC if the average value of the inductor current is constant while the ripple of the dc bus voltage is small. For reducing the SHC in the inductor current, a virtual series impedance, whose magnitude is high at twice the output voltage frequency (2fo) but low at other frequencies, is introduced in series with the filter inductor. For improving the dynamic performance, a virtual parallel impedance, whose magnitude is infinite at 2fo but low at other frequencies, is introduced in parallel with the dc bus capacitor. Based on the virtual-impedance-based approach and the closed-loop-design-based approach, this chapter not only derives a variety of SHC reduction control schemes but also provides an insight into their inner relationships. Considering both the SHC reduction and the system stability, a step-by-step closed-loop parameters design approach is also presented. Finally, a 1-kVA prototype is built and tested, and experimental results are provided to compare and evaluate the performance of different SHC reduction control schemes.
Xinbo Ruan, Li Zhang, Xinze Huang, Fei Liu, Guoping Zhu, Shiqi Kan
Chapter 4. Second Harmonic Current Reduction for Two-Stage Single-Phase Inverter with Boost-Derived Front-End Bus-Voltage-Controlled Converter
Abstract
This chapter focuses on the second harmonic current (SHC) reduction for the two-stage single-phase inverter with boost-derived front-end bus-voltage-controlled converter (BVCC). To reduce the SHC, a virtual series impedance, which has high impedance at twice the output frequency (2fo) while low impedance at other frequencies, is introduced in series with the boost-diode (or the boost-inductor) to increase the impedance of the boost-diode (or boost-inductor) branch at 2fo. For having good dynamic performance, meanwhile, a virtual parallel impedance, which exhibits infinite impedance at 2fo while low impedance at other frequencies, is introduced in parallel with the dc bus capacitor to reduce the output impedance of the boost-derived converter at the frequencies except for 2fo. The virtual series impedance is realized by the feedback of the boost-diode current or the boost-inductor current, while the virtual parallel impedance is implemented by the feedback of the dc bus voltage. On account of the virtual-impedance-based approach and the closed-loop-design-based approach, a variety of SHC reduction control schemes are derived. With considerations for both the SHC reduction and the system stability, a step-by-step closed-loop parameters design approach is also presented. Finally, a 1-kVA prototype is built and tested in the lab, and experimental results are provided to verify the effectiveness of the proposed SHC reduction control schemes.
Xinbo Ruan, Li Zhang, Xinze Huang, Fei Liu, Guoping Zhu, Shiqi Kan
Chapter 5. Second Harmonic Current Reduction for Two-Stage DC-AC Inverter with DCX-LLC Resonant Converter in the Front-End DC-DC Converter
Abstract
In this chapter, the second harmonic current (SHC) reduction for the two-stage dc-ac inverter with DCX-LLC resonant converter in the front-end dc-dc converter is studied. The small-signal model of the DCX-LLC resonant converter is derived and based on which, the unified small-signal model of the preregulator + LLC converter is built. Then, the basic ideas for reducing the SHC are proposed, including the determination of the filter capacitors in the preregulator + LLC converter and the control approaches. After that, from a perspective of output impedance, the control schemes for reducing the SHC in the front-end preregulator + LLC converter are proposed. By inserting a notch filter in the voltage loop and/or introducing a virtual impedance in series with the output rectifier of the LLC resonant converter, the output impedance of the preregulator + LLC converter at 2fo is increased, and thus the SHC can be reduced. Finally, a 6-kVA two-stage three-phase dc-ac inverter with boost + LLC converter as the front-end dc-dc converter was fabricated and tested in the lab. The experimental results are provided to verify the proposed control schemes.
Xinbo Ruan, Li Zhang, Xinze Huang, Fei Liu, Guoping Zhu, Shiqi Kan
Chapter 6. Second Harmonic Current Reduction for Two-Stage Single-Phase Inverter with Front-End Bus-Current Controlled Converter
Abstract
This chapter studies the control schemes of reducing the second harmonic current (SHC) for the two-stage single-phase photovoltaic (PV) grid-connected inverter where the front-end dc-dc converter is operated as a bus-current controlled converter (BCCC). To limit the SHC in the BCCC and the PV panel, the input voltage loop gain of the BCCC should be high enough at twice the output frequency (2fo). Since there is a −180° phase abrupt at the resonant frequency of the input side filter capacitor and the inductor, the system may be unstable. To cope with this problem, the inductor current feedback active-damping scheme (ADS) is adopted. For further improving the input voltage loop gain at 2fo, the proportional-integral- resonant regulator with active-damping scheme is proposed in this chapter. Besides, a step-by-step closed-loop parameters design method is presented. Finally, a 3-kW two-stage single-phase grid-connected PV inverter prototype is fabricated and tested in the lab, and the experimental results are provided to verify the feasibility of the proposed control schemes.
Xinbo Ruan, Li Zhang, Xinze Huang, Fei Liu, Guoping Zhu, Shiqi Kan
Chapter 7. Second Harmonic Current Reduction for DC-DC Converter in Two-Stage PFC Converters
Abstract
This chapter studies the approaches for reducing the second harmonic current (SHC) in the dc-dc stage in the two-stage single-phase power factor correction (PFC) converter. The dc-dc stage is used to regulate the output voltage or the dc bus voltage in different applications, When the dc-dc stage regulates the output voltage, it is pointed out that the control bandwidth of the dc-dc stage is required to be high enough and the dc bus capacitor should be large enough to suppress the SHC, and the design of the dc bus capacitor is given. When the dc-dc stage regulates the dc bus voltage, a virtual impedance is added in series with the input/output of the dc-dc stage to suppress the SHC, and a virtual impedance is added in parallel with the dc bus to improve the dynamic performance. Based on that, three specific control schemes are presented for the dc-dc stage to suppress the SHC, and the detailed parameters design procedure is also presented. A 3.3-kW two-stage single-phase PFC converter is fabricated in the lab, and the experiment results are provided to verify the effectiveness of the control schemes for reducing the SHC.
Xinbo Ruan, Li Zhang, Xinze Huang, Fei Liu, Guoping Zhu, Shiqi Kan
Chapter 8. Control Schemes for Reducing Second Harmonic Current in AC-DC-AC Converter System
Abstract
In the ac-dc-ac converter system, the second harmonic current (SHC) appears at the output of the ac-dc rectifier and input of the dc-ac inverter, which propagates to the dc-dc converter, leading to poor performance. In this chapter, the generation and propagation mechanism of the SHC in the ac-dc-ac converter system is analyzed. Then, from a perspective of control bandwidth and dc bus port-impedance, the basic ideas for reducing the SHC in the dc-dc converter with different control targets are proposed. Based on that, the virtual-impedance-based control scheme is proposed to increase both the input impedance and output impedance of the dc-dc converter. In addition, the realization and design guideline of the virtual impedance is presented. Finally, a single-phase 3-kVA ac-dc-ac converter system is fabricated and tested in the lab. The experimental results are provided to verify the effectiveness of the proposed SHC reduction control scheme.
Xinbo Ruan, Li Zhang, Xinze Huang, Fei Liu, Guoping Zhu, Shiqi Kan
Chapter 9. A Current Reference Feedforward Scheme for the Second Harmonic Current Compensator
Abstract
This chapter presents the control schemes for the second harmonic current compensator (SHCC) to compensate the second harmonic current (SHC) in two-stage single-phase converters. The dual closed-loop control scheme for the SHCC is firstly proposed. Due to the limited current regulator gain at the second harmonic and its multiples, the port current of the SHCC cannot accurately track the SHC. To improve the tracking accuracy of the port current, the current reference feedforward control scheme is then proposed, where the required harmonic components are introduced into the modulation signal by the feedforward path and a series of calculation operations. Furthermore, the current reference feedforward control scheme is simplified, and the reciprocal and square rooting circuits are removed, leading to reduced complexity of the control circuit. Finally, a 33.6 W light-emitting diode (LED) driver with SHCC is fabricated and tested in the lab, and the experimental results are presented to verify the effectiveness of the proposed control schemes.
Xinbo Ruan, Li Zhang, Xinze Huang, Fei Liu, Guoping Zhu, Shiqi Kan
Chapter 10. One-Cycle Control for Electrolytic Capacitor-Less Second Harmonic Current Compensator
Abstract
In this chapter, electrolytic capacitor-less second harmonic current compensator (SHCC) is presented to compensate the SHC. The SHCC has two operating modes, namely, charging mode and discharging mode. To attain an excellent SHC compensation performance, a hybrid one-cycle control (OCC) is proposed to regulate the port current of the SHCC, ensuring stable operation in both charging modes and discharging mode. To avoid the mode detection required in the hybrid OCC and realize seamless transition between the two modes, the OCC with dc bias is further proposed. A 1-kVA two-stage single-phase dc-ac inverter with the SHCC is fabricated and tested, and the experimental results are provided to verify the effectiveness of the proposed control schemes.
Xinbo Ruan, Li Zhang, Xinze Huang, Fei Liu, Guoping Zhu, Shiqi Kan
Chapter 11. A Virtual-Impedance-Based Control Scheme for Modular Electrolytic Capacitor-Less Second Harmonic Current Compensator
Abstract
The second harmonic current compensator (SHCC) can be added into the single-phase converters for compensating the second harmonic current (SHC) and thus removing the undesired electrolytic capacitor. In this chapter, a virtual impedance, which is in the form of a capacitor and a resistor connected in parallel, is introduced to be in parallel at the bus-side port of the SHCC for effectively compensating the SHC while guaranteeing the system stability. This virtual parallel impedance is realized by the feedforward of the bus-side port voltage of the SHCC, and thus the SHCC can be designed as an independent module. The closed-loop parameters design of the SHCC is also presented. A 3.3-kW prototype of a two-stage single-phase PFC converter is built and tested in the lab, and the experimental results verify the effectiveness and feasibility of the proposed control method.
Xinbo Ruan, Li Zhang, Xinze Huang, Fei Liu, Guoping Zhu, Shiqi Kan
Chapter 12. Adaptive Storage Capacitor Voltage Control for Second Harmonic Current Compensator in Single-Phase Converters
Abstract
For the second harmonic current compensator (SHCC) in the single-phase converters, the storage capacitor voltage should be controlled for ensuring normal operation. Basically, the storage capacitor voltage ripple becomes smaller as the load decreases. Thus, when the average value of the storage capacitor voltage is controlled, the voltage difference between the dc bus voltage and storage capacitor voltage will increase at light load, making the SHCC produce higher power losses. To solve this problem, the adaptive storage capacitor voltage control is proposed for the SHCC in this chapter. Specifically, the maximum storage capacitor voltage control is proposed for the buck-type SHCC, making the storage capacitor voltage adaptively increase as the load becomes lighter. By contrast, the minimum storage capacitor voltage control is proposed for the boost-type SHCC, making the storage capacitor voltage adaptively decrease as the load becomes lighter. In this manner, the voltage difference between the dc bus voltage and the storage capacitor voltage will be minimized over the entire load range, saving the power losses by the SHCC. Finally, a two-stage dc–ac inverter with buck-type SHCC and a light-emitting diode (LED) driver with boost-type SHCC are respectively fabricated to verify the effectiveness of the proposed adaptive storage capacitor voltage control.
Xinbo Ruan, Li Zhang, Xinze Huang, Fei Liu, Guoping Zhu, Shiqi Kan
Chapter 13. Stability Analysis of Two-Stage Single-Phase Converter System Adopting Electrolytic Capacitor-Less Second Harmonic Current Compensator
Abstract
For the two-stage single-phase converters, including the power factor correction (PFC) ac–dc converter and dc–ac inverter, a second harmonic current compensator (SHCC) can be introduced to handle the second harmonic current (SHC) for removing the undesired electrolytic capacitor. Consequently, the two-stage single-phase converter becomes a multi-converter system. In this chapter, the ac–dc stage or dc–ac stage in the system is categorized into two types in terms of the control objectives, i.e., the bus-voltage-controlled converter (BVCC) and the bus-current controlled converter (BCCC). The SHCC is a BCCC since its bus-port current is directly controlled. The system stability is investigated with the impedance-based stability criterion, and it is found that the system stability is different when the ac–dc stage or dc–ac stage is operated as a BVCC or a BCCC. Specifically, only when the ac–dc stage is operated as a BVCC, the system is unstable; while for other cases, the system is certainly stable. For the applications where the ac–dc stage is operated as a BVCC, a virtual resistor is introduced and realized by the control scheme of the SHCC to ensure the system stability. Finally, a 3.3-kW two-stage single-phase PFC ac–dc converter is fabricated and tested to verify the theoretical analysis and the proposed control scheme.
Xinbo Ruan, Li Zhang, Xinze Huang, Fei Liu, Guoping Zhu, Shiqi Kan
Backmatter
Metadaten
Titel
Second Harmonic Current Reduction Techniques for Single-Phase Power Electronics Converter Systems
verfasst von
Prof. Xinbo Ruan
Dr. Li Zhang
Dr. Xinze Huang
Fei Liu
Prof. Guoping Zhu
Prof. Shiqi Kan
Copyright-Jahr
2022
Verlag
Springer Nature Singapore
Electronic ISBN
978-981-19-1547-5
Print ISBN
978-981-19-1546-8
DOI
https://doi.org/10.1007/978-981-19-1547-5