Secondary Side Voltage Research Articles

Development of Wireless In-Wheel Motor Using Magnetic Resonance Coupling

In-wheel motors (IWMs) in electric vehicles are particularly important for motion control. A conventional IWM is powered from a battery aboard the vehicle via cables. Since power cables and signal cables of an IWM are exposed to harsh environments, they can possibly become disconnected by high acceleration or vibration. In order to overcome this problem, the wireless-in wheel motor (W-IWM) has been proposed. The risk of disconnection would disappear if the cables of the IWM are removed. One way to implement wireless power transfer is by utilizing the magnetic resonance coupling method. However, motion of the W-IWM, and thus, a misalignment between the wheel and the vehicle, leads to variations in the secondary-side voltage provided. To account for this, this paper discusses two new control methods. One proposed method maintains the secondary voltage using a hysteresis comparator. The other proposed method estimates the secondary inverter output power, applying it to a feedforward controller in order to keep the secondary dc-link voltage constant. Experimental results show that these methods can drive a W-IWM effectively with high efficiency.

Modular Matrix Converter Based Solid State Transformer for smart grids

This paper proposes a grid forming Modular Matrix Converter Based Solid State Transformer for smart grids. The Modular Matrix Converter Based Solid State Transformer regulates the voltage amplitude and frequency of the low voltage grid, enabling sag and swell mitigation. Each module includes a three-phase Matrix Converter, connected to a three-phase High Frequency Transformer, whose secondaries are connected to three Single-Phase Matrix Converters. Input and output LC filters are required to guarantee nearly sinusoidal waveforms in the MV connection and in the LV grid.The three-phase Matrix Converter uses a modified High Frequency Space Vector Modulation, with a novel feature to guarantee the non-saturation of the High Frequency Transformer at 2kHz operation. To restore the waveform that would result from the original Space Vector Modulation the High Frequency Transformer is connected to three Single-Phase Matrix Converters. Combining the advantages of Matrix Converters with high frequency operation, the volume of the galvanic isolation transformer can be reduced, and using decoupled controllers, the output voltage waveforms are regulated both in amplitude and frequency, to form a low voltage grid.The proposed Modular Matrix Converter Based Solid State Transformer is simulated and the obtained results show that it is able to regulate the secondary side voltage and frequency, even in a bidirectional power flow operation scenario, allowing power factor correction in the local MV connection, and providing mitigation capability of voltage sags and swells up to 20%, therefore improving power quality in the smart grid.

Analysis and Simulation of Full-Bridge Boost Converter using Matlab

Improvement of high power and high performance applications causes attention to the DC-DC converter topologies. In this paper we analyze and simulate full-bridge boost converter, an isolated DC-DC converter. The advantages of isolated DC-DC converters include high efficiency, low manufacturing cost, safety, electrical isolation using transformer. The transformer is used to produce a higher voltage in secondary voltage side. Matlab Simulink is used for simulation of this converter. Nominal input voltage in this simulation is 30V and the output voltage is 55V. Also other parameters are given in this paper.

The Influence of Electric Parameters on Film Quality of GZO Thin Film Fabricated by APPJ Process

In this paper, APPJ (Atmospheric pressure Pules arc Plasma Jet) is used to generate a DC pulse source depositing GZO thin film under atmospheric pressure. Thus, no vacuum chamber needed leads to the cost downward. With scanning operation, makes single unit area into large size area. Several key process parameters have been studied, including the power supply voltage, DC pulse, the length of the nozzle extended head, and depositing gap to understand their relationship with the film quality and atmospheric plasma state.In this study, with adjusting DC pulse, the pulse frequency is found to have a great impact on the plasma state and the film quality. When the pulse frequency is near 25 kHz, lower sheet resistance can be retained. Besides, adjusting Toff time, the plasma and thin film quality are influenced more than Ton time. By changing the power supply voltage, the secondary-side voltage decreases with increasing of the instantaneous current; moreover, the plasma will become more intense.

An Electrolytic-Capacitor-Free Single-Phase High-Power Fuel Cell Converter With Direct Double-Frequency Ripple Current Control

This paper proposes a direct double-frequency ripple current control in a single-phase high-power fuel cell converter that can achieve low-frequency ripple-free input current without using large electrolytic capacitors. To eliminate the double-frequency ripple current disturbance introduced by the single-phase inverter load, a proportional-resonant controller is developed to achieve an extra high control gain at designed resonant frequency. This high gain can be viewed as the virtual high impedance for blocking the double-frequency ripple energy propagation from inverter load to fuel cell stack. More particularly, the proposed control system can realize the utilization of all capacitive ripple energy sources in the system by regulating all the capacitors to have large voltage swing. In addition, this voltage swing is synchronized to keep real-time balancing of the transformer primary- and secondary-side voltages. As a result, the zero-voltage-switching operation for all switching devices in the dc-dc stage can be guaranteed. The controller design guidelines are derived based on the system small-signal model. The experimental results are presented to validate the theoretical analysis and proposed technology.

Study on Maximize Efficiency by Secondary Side Control Using DC-DC Converter in Wireless Power Transfer via Magnetic Resonant Coupling

Wireless power transfer via magnetic couple resonance has been widely studied as an attractive research target. In order to improve the transmitting efficiency, not only increasing performance of antenna is important but also controlling secondary (receiver) side input impedance value. As a method of controlling secondary input impedance, the method of using a DC-DC converter is proposed in previous research. Mutual inductance what related to transmitting distance and load resistance value is needed to know for control the DC-DC converter. Moreover, the transmitting distance and load resistance has changed in actual WPT situation. Therefore, control method for DC-DC convertor what keep best efficiency in actual WPT situation is needed. In this paper, the novel method of controlling a DC-DC converter for maximize efficiency which used for wireless power transfer via magnetic couple resonance is proposed. A mutual inductance can be known the voltage sensor in secondary side by setting power supply voltage constant. Furthermore, efficiency could be maximized regardless of the state of load by controlling a DC-DC converter so that the secondary side voltage constant value. This principle was explained by equation. Thereby, even when transmission distance and a load resistance value change, wireless power transfer system keep best efficiency automatically without communication between primary to secondary side.

Design and analysis of a high frequency DC–DC converters for fuel cell and super-capacitor used in electrical vehicle

This work focuses on the application of the high frequency DC–DC converters used in electric vehicles. Two converters are necessary. The first converter is interposed between the fuel cell and the DC–AC inverter. It is unidirectional. The second one is used as interface between the ultra-capacitor and the DC–AC inverter. It allows the bidirectional of the power transfer. Each converter is composed of two full bridges, LC resonant filter and two planar transformers. The use of high frequency transformer allows to minimize the size and weight of the converter, produce a higher voltage in secondary side from input voltage (fuel cell or super-capacitor) and isolate the full bridges. The control strategy of the converters is the phase shift. The converters have been designed, realised and controlled by an FPGA board. To demonstrate the converters feasibility, two converters are implemented and tested. The switching frequency of two converters is 20 kHz. The first converter has a 24-V input and 200 V/1.2 kW output. But, the second converter has a 12.5-V input and 100 V/400 W output.

1-W 3.3–16.3-V Boosting Wireless Power Transfer Circuits With Vector Summing Power Controller

This paper presents SD-card-size wireless power transfer system for large-volume contactless memory cards. Voltage is boosted simultaneously with power transfer, which eliminates the dc-dc converter or charge-pump circuit for data write operation into the flash memory chip. The proposed approach reduces the number of components and BOM cost and improves the total power efficiency. A vector summing technique is proposed to control the transmitting power and secondary side voltage. The transmitter and rectifier have been designed and fabricated using 0.18-μ m-CMOS with high voltage option. Voltage boost from 3.3 to 16.3 V and 1-W power transfer with 50% total efficiency have been successfully demonstrated, and the response time for the power control loop is shorter than 35 μs .

Detailed Review and Application of the 3-Phase Self-Limiting Transformer with Magnetic Flux Applied

The paper describes in detail the 3-phase self-limiting transformer with magnetic flux applied and contains measured results. The solution includes two independent iron cores. I applied two pieces of iron cores with 3 limbs on each. One of the iron cores contains the 3 primary coils on the limbs respectively and the other iron core also contains 3 secondary coils. As I use two iron cores the loss, the size, the weight and the cost are higher compared to the conventional transformers but this solution has several advantages. For example, the fault power is less, switching is fast. In the case, when there is no load on the secondary side and primary voltage increases, the arrangement is able to break coupling between the primary and secondary sides. The work has been carried out by me as a novel possibility of application of the principle of magnetic flux constancy in the closed loop.

Analysis of a Commercial Wind Farm in Taiwan Part II: Different Current-Limit Reactors and Load Tap Changers on System Performance

This paper presents the effects of installing variable current-limit reactors (CLRs) and adjusting load tap changers (LTCs) on the performance of a commercial wind farm in Taiwan using computer simulations. The companion paper (Part I) demonstrates the field-measured results, simulation model, and simulation results of the studied Jang-Bin wind farm with 23 2-MW doubly fed induction generator-type wind turbine generators connected to the utility system through a 23/161-kV 60-MVA step-up main transformer (MT) from six feeders. Six CLRs, which were originally designed to limit short-circuit currents under faulted conditions, are connected in series with the six feeders. The LTCs of the MT are used to adjust/regulate the secondary-side voltage at the 23-kV bus. Some simulated steady-state and transient results of the studied wind farm with variable values of the proposed CLRs and LTCs are analyzed and compared.

Active asynchronous secondary side voltage clamping

An asynchronous active voltage clamp for the secondary side of switching DC-DC converters is proposed. The control of the proposed clamping circuit is independent from the main converter, thus allowing use of a physically small inductor and offering increased control over the clamping operation. Measurements on a 1 MHz implementation of the asynchronous active voltage clamp on the secondary side of a prototype 220 kHz phase shifted full bridge DC-DC converter confirm the effectiveness of the voltage clamping and the improved converter efficiency.

A Universal Grid-Connected Fuel-Cell Inverter for Residential Application

This paper describes a universal fuel-cell-based grid-connected inverter design with digital-signal-processor-based digital control. The inverter has a direct power conversion mechanism with a high-frequency zero-voltage-switched dc/ac primary-side converter followed by a pair of ac/ac cycloconverters that operates either in parallel or in series to simultaneously address the issues of universal output and high efficiency. The critical design issues focus on the impact and optimization of transformer leakage inductance with regard to effectiveness of zero voltage switching of a primary-side converter, duty-cycle loss, resonance, and voltage spike that has effect on the breakdown voltage rating of the cycloconverter devices. An additional concept of dynamic transformer tapping has been explored to address the impact of varying input voltage on secondary-side voltage spike and inverter efficiency. Finally, detailed grid-parallel and grid-connected results are presented that demonstrate satisfactory inverter performances.

An Adaptive Distance Relay Based on Transient Error Estimation of CVT

Simple delay solutions are usually used to prevent transient overreach caused by the transient error of a capacitor voltage transformer (CVT), which is very harmful to the safety and stability of operation of the power system. A proposed real-time CVT transient error estimation approach based on the chosen fundamental wave algorithm and the rated CVT parameters consists of two stages. The first stage obtains the error coefficient. The second stage estimates the measured error of the voltage amplitude according to the secondary side voltage. A novel adaptive distance relay approach is proposed, which can adjust operating thresholds according to the error. The approach hardly affects the performance for lines of normal length and operates rapidly for short lines with close-in faults, which is verified by the simulation studies. The overall performance is improved greatly in comparison with the general approach for distance relays