Xiaosheng Liu

S/CLC Compensation Topology Analysis and Circular Coil Design for Wireless Power Transfer

Wireless power transfer (WPT) has drawn a lot of attention due to its inherent advantages and great potential in various applications. This paper proposes a novel compensation topology composed of one compensation inductor and three compensation capacitors. The newly proposed compensation topology, named as S/CLC, provides the advantages of constant voltage output and easy achievement of zero phase angle and zero voltage switching. It is also free from the constraints imposed by the loosely coupled transformer (LCT) parameters. All the above-mentioned merits are theoretically analyzed and verified by simulation and experiment. Compared to double-sided LCC compensation topology, S/CLC compensation topology needs less compensation components, meaning lower cost, smaller size, higher power density, and greater potential in practical applications. The optimization of a circular pad is conducted as well since the properties of the LCT have a significant impact on the performance of a WPT system. A circular pad is manufactured in terms of the conclusions obtained from the optimization. The coupling coefficient Circular pad design, constant voltage output (CVO), wireless power transfer (WPT), zero phase angle (ZPA), zero voltage switching (ZVS).of the circular pad is quite appealing, demonstrating the validity of the optimization.

An LC/S Compensation Topology and Coil Design Technique for Wireless Power Transfer

Wireless power transfer (WPT) has attracted a lot of attention these years due to its convenience, safety, reliability, and weather proof features. First and foremost, the consistency of mutual model and T model of loosely coupled transformer (LCT) was deduced. The application scenarios of these two models were then concluded so as to choose suitable model in circuit analysis. Then, a new WPT compensation topology, which is referred to as LC /S compensation topology and consists of one inductor and two capacitors, is proposed. The constant-current-output (CCOut) characteristic of the newly proposed topology is analyzed in detail on the basis of the discussion about LC and CL resonant tank. The equivalent resistance of the rectifier, filter, and resistor circuit is also analyzed to simplify circuit analysis. Then, the current and voltage stress on each component and the system performance under imperfect resonant condition are studied with the help of MATLAB. The LCT is deliberately designed by the finite element analysis software ANSYS Maxwell as well because the coupling coefficient, primary, and secondary self-inductance have a significant impact on system efficiency, power level, and density. The LCT design approach employed in this paper can be extended to magnetic design of almost all WPT systems. Theoretical analyses are verified by both Pspice simulation and practical experiments. Practical output currents with transient loads show an excellent CCOut characteristic of LC/S compensation topology.

A Single-Stage LED Driver With High-Performance Primary-Side-Regulated Characteristic

A traditional flyback LED driver is limited by its low performance, which usually does not meet the power factor (PF) and total harmonic distortion requirements according to Energy Star or IEC61000-3-2. The control loop from the secondary side to the primary side has low reliability and employs more components, which reduces the power density of the system and increases the cost. In this brief, based on single-stage single ended primary inductor converter (SEPIC) and flyback converter, a primary-side-regulated LED driver is proposed to improve the performance of the system. Working in DCM, the SEPIC circuit realizes the PF correction naturally. For the flyback converter, the proposed primary-side-regulated method improves the power density and guarantees accurate control of the output current. A 100-W prototype based on SEPIC-flyback was built to verify the analysis and the experimental results coincided with the analysis results satisfactorily.

A double-T-type compensation network and its tuning method for IPT system

This paper presents a new design strategy for S-LCC type compensation network in Inductive Power Transfer (IPT) systems. It was found that four resonant elements (three capacitors and one inductor) can compose two symmetric T type resonant tanks, which is well-known for its impedance transformation characteristic and reciprocity between voltage source and current source. A simplified analytical technique is used to calculate the voltage gain and parameters for each resonant element. Besides, the proposed tuning method for S-LCC network has negligible response to high-order harmonics, allowing wide range of output voltage regulation and easy implementation of ZVS. To verify the analysis, a prototype with 20mm gap was fabricated and tested. An overall efficiency 86% was achieved from DC 60V to DC 24V.

A novel compensation topology for Inductively Coupled Power Transfer

Compensation is a vital part in Inductively Coupled Power Transfer (ICPT) to achieve higher efficiency, power density and reliability. This article proposes two unilateral LC compensation topologies for ICPT system after thorough theoretical analysis, which achieve both zero-voltage switching and constant voltage output characteristics over a wide range of load. A 300W phase-shifted full bridge DC-DC Wireless Power Transfer device is designed and built which achieves an efficiency of 87.8% using proposed structure.

A Novel Parameter Tuning Method for a Double-Sided LCL Compensated WPT System With Better Comprehensive Performance

Wireless power transfer (WPT) has attracted a large amount of attention owing to its inherent advantages such as convenience, safety, low maintenance, being weather proof, etc. A parameter tuning method is crucial for a WPT system due to its function of reducing reactive power and improving system efficiency. Three deficiencies of the conventional double-sided inductor–capacitor–inductor (DS-LCL) compensated system, i.e., low design freedom, weak high-order harmonic suppression capability, and discontinuous input current of a full-wave diode rectifier (FDR), are first analyzed by means of theoretical derivation, numerical calculation, and Pspice simulation. In order to overcome these disadvantages, a novel parameter tuning method is proposed. The characteristic of constant current output of the proposed DS-LCL system is analyzed, followed by a detailed derivation about secondary compensation inductance. Theoretical analysis indicates that the proposed system has four attractive characteristics: higher design freedom, reduced coil current, enhanced high-order harmonic suppression capability, and continuous input current of the FDR. The overall efficiencies of two comparative WPT prototypes, tuned by conventional and proposed methods, are 87.3% and 90.2%, respectively. Experimental results show great coincidence with theoretical analysis, demonstrating the superiority of the newly proposed parameter tuning method.

A novel modulation and demodulation method for wireless power and data transmission

This paper proposes a novel wireless power and data transmission (WPDT) scheme to meet the communication requirements in a wireless power transfer system. The scheme borrows the idea of power line communication which modulates a high-frequency data carrier into fundamental AC electric wave. The scheme provides a number of appealing characteristics, such as shared magnetic linkage, low cost, small size, high power density, weak interference to power transfer and high data bit, as well as limited bit error rate. The cross interference between power transfer and data transmission is analyzed in depth. The parameter design methods concerning communication cells are given. Data transmission model is built as well to obtain optimum system performance. Eight binary data 10011010 are correctly transferred at a bit rate of 28.33 kbps, validating the feasibility of proposed WPDT scheme.

A dynamic wireless power transfer system with parallel transmitters

This paper proposes a dynamic wireless power transfer system with parallel transmitters for electric vehicles. The transmitter consists of two DD type coils which connect with one inverter in parallel. To overcome the power-null phenomenon, one additional rectangular coil named Q coil is added into the DD type receiver, composing the DDQ type receiver. One big challenge in dynamic wireless power transfer system is the output power pulsation. To mitigate that challenge, the Q coil is optimized using Finite Elements Method. For the compensation network, a double-side LCC topology is adopted. Each LCC network together with the self-inductance of the loosely coupled transformer composes a symmetric T type network, which can turn a constant sinusoidal voltage source into a constant sinusoidal current source. It is shown that constant current output characteristic the symmetric T type network can great simplify the design. Moreover, to maximize the efficiency of the whole system, an optimized design method for the receiver is proposed. Finally, a prototype is fabricated to verify the aforementioned analysis.

Research on the relations between the ballast conditions and the luminous efficacy of low pressure sodium lamp

To fully incarnate the characteristic of the high luminous efficacy of the low pressure sodium lamp (LPS) and to optimize the efficiency of the system which is made up of the LPS and the electronic ballast, a detailed research on the system has been done. Theoretically, the luminous efficacy of the LPS and the efficiency of the electronic ballast are both vary obviously with the work frequency of the LPS, and the trend is opposite, it means there is a frequency point which can optimize the efficiency of the system. The researched system is composed of the ballast with the input of 55 W, by measuring the luminous flux of the LPS and the input power of the ballast, the relation between the efficiency of the system and the ballast conditions is analyzed. The experimental results show that the proper ballast technologies can optimize the efficiency of the system.

A high-power-factor integrated-stage AC-DC LED driver based on flyback-class E converter

This paper presents an integrated-stage AC-DC LED driver based on Flyback and Class-E converter with high power factor. The Flyback circuit works in discontinuous conduction mode (DCM) to realize the power factor correction (PFC) function, and the Class-E circuit is used as DC-DC converter to transform the energy to the LED load. The integrated topology can decrease the cost of system. Moreover, the Class-E converter provides soft switching operation in resonant mode, which can improve the converter efficiency. The active switch is operated with constant duty radio and pulse frequency modulation (PFM). A 100W prototype is presented in experimental condition to certify the validity of the proposed integrated-stage LED driver.