Research on Push-pull-type Inductively Coupled Power Transfer System for ZVS

Inductive coupled power transfer (ICPT) is an emerging technology that may create new applications for wireless power charging. However, low efficiency is one of the main obstructing factors for promoting this technology. In this paper, a method of resonant frequency optimization based on resonant current calculation at the secondary side of the system is proposed to achieve higher efficiency. In order to research the influences of resonant frequency on system efficiency, the resonant current of the secondary side circuit is calculated, from which the phase shift angle between resonant current and voltage, and the conduction angle of diodes of rectifier can be obtained. Furthermore, a set of simulations are performed to find the optimized resonant frequency relationship between output power and the resonant current amplitude, because the copper loss and core loss of a loosely coupled transformer are all positively associated with resonant current. Finally, a 1.6 kW ICPT system is built and tested to verify the effectiveness of the proposed system. The results prove that the optimized resonant frequency can achieve a system efficiency of 92.5%, when that of a conventional system with a resonant frequency equal to the working frequency is 92%.

In this paper, the generalized model of an inductively coupled power transfer (ICPT) system, which could transfer power efficiently, is built to predict the output power and voltage of the system. The basic concept and structure of ICPT systems is described and a current source push-pull resonant converter for ICPT is presented, and some characteristics of the ICPT system are discussed. The equivalent circuit model is built with mutual inductance concept. Based on this model, equations are obtained to calculate the output power, voltage and resonant frequency, which are verified by experimental results. A brief loss analysis based on Steinmetz equation is given to explain the difference between the predicted and measured values, which are verified by experimental results to make the model more accurate.

A study on renewed perspectives of electrified road for wireless power transfer of electric vehicles

Autonomous Underwater Vehicle non-contact charging system using a separate structure, When the technology is used in the underwater environment, the inductive coupled power transmission system will produce a gap and eccentricity under the influence of the water shock, causing the coupling state changed, which will affect the output power. This paper presents a control algorithm based on neural network system that compensate the system output power by adding a DC/DC switching according to the changes of the magnetic coupling state, in order to achieve a stable output voltage.

Dual Active Bridge (DAB) Converter and PushPull Converters are mainly used for Conversion of power with large cycles per second. Dual active bridge converter consists of couple of full bridge converters linked through a transformer. Two way power flow capacity, high power density, high proficiency, soft switching, less number of passive elements and galvanic separation are the important characteristics of DAB pulling in industry. The push-pull converter is utilized as DC-DC converters are reasonable for low and medium power application. High efficiency, low switching loss and high power density are the important characteristics of this converter. By increasing the switching frequency, it results in the reduction of complexity of the circuit. However the switching loss increases as the switching frequency is increased. In this paper, the study is focused on a comparative analysis of DAB converter and Push-Pull converter.

In this paper, a novel soft switching push-pull LC resonant DC-DC converter for energy sources is presented. In a high step-up converter, the input of primary side possesses low voltage and high current, so the losses caused by the current account for most of the total power loss. At the same time, the high-voltage stress of the high-voltage output components on the secondary side is also a major problem. Therefore, a high-gain isolated push-pull converter with a secondary-side resonant circuit is proposed, so that the primary-side switches have zero voltage switching (ZVS) and the secondary-side diodes have zero current switching (ZCS). The push-pull structure can reduce the number of active switches, so that the total power loss on the primary side can be reduced. The converter has a resonant tank circuit arranged between the secondary side of isolation transformer and the high-voltage output rectification module. The high-voltage output rectifier module adopts a full-bridge architecture suitable for high-voltage coupling connection. The low-side power switching module adopts a push-pull architecture suitable for low-voltage and high-current applications. The resonant tank circuit uses an inductor–capacitor (LC) structure to improve the resonant tank circuit, which achieves soft switching during power transfer, increasing the efficiency of the converter and improving the electromagnetic compatibility. The main advantage of this technology is that the secondary-side leakage inductance of transformer and the resonant capacitance are connected in series to achieve ZVS for switches and ZCS for diodes. Finally, a prototype of a high-gain push-pull resonant converter was established. The converter was operated at a fixed switching frequency of 135 kHz and a duty cycle of approximately 0.5. The efficiency of the converter can reach 97.1% under experimental tests at an output voltage of 400 V and a rated output power of 500 W.

Wireless power transfer (WPT) is a popular research field in recent years and can be categorized into three approaches: inductive coupling, laser beaming, and microwave power transmission (MPT). MPT system operates at the microwave and transfers the energy over more than a few wavelengths. It has its unique advantages of supplying power to non-accessible and mobile receivers. The overall efficiency, which is the ratio between available DC power at the receiver and supplied DC power at the transmitter, depends on both circuit design and wave propagation. As a comprehensive theory of MPT system is not available, this chapter starts with the study of MPT system from the perspectives of mathematical formulation and the experiment in the indoor environment, in Sect. 3.1. The preliminary study leads to the conclusion that highly directional wireless transmitter is very useful in the MPT system for achieving high transmission efficiency. For this reason, phased array antennas with beamforming functionality are usually used to direct the electromagnetic wave toward mobile receivers, and adaptive array algorithms are implemented to enable wireless power focusing in the complex environment. Section 3.3 presents a novel beamforming algorithm, which is proven to give the optimal transmission efficiency and applies to the arbitrarily positioned unequal array based on our problem formulation. To verify this algorithm, Sect. 3.4 validates it with numerical electromagnetic simulation in different cases. The numerical comparison in these examples shows that this algorithm gives higher transmission efficiency over other optimal beamforming algorithms discussed in Sect. 3.2.

To date inductively coupled power transfer (ICPT) systems have already found many practical applications including battery charging pads. In fact, current charging platforms tend to largely support only one- or two-dimensional planar movement in load. This paper proposes a new concept of extending the aspect ratios of the operating power transfer volume of ICPT systems to support arbitrary three dimensional load movements with respect to the primary coils. This is done by use of modern finite element method analysis software to propose the primary and secondary magnetic structures of such an ICPT system. Firstly, two primary magnetic structures are proposed based on contrasting modes of operation and different field directions. This includes a single-phase and multi-phase current model. Next, a secondary magnetic structure is customized to be compatible with both primary structures. The resulting system is shown to produce a 3D power transfer volume for battery cell charging applications.

The operation of a push-pull converter with an input choke and an autotransformer current divider operating in the soft switching mode of all transistors, which is provided by reversing the instantaneous value of the inductor current, is considered. The implementation of the soft switching condition of all transistors, except for reducing dynamic losses on them, leads to an in-crease in dynamic losses in the inductor and static losses in the circuit due to an increase in the effective value of the inductor current. As a result of the experiment, it was shown that an increase in the variable component of the inductor current leads to an increase in the converter efficiency to a certain level of the average inductor current.

Inductive power transfer (IPT) and capacitive power transfer (CPT) are two basic near-filed approaches for efficient wireless power transfer. Although they share similar system configurations, it is the coupler that determines power transfer characteristics and coupling efficiency. Given the same coupling space (i.e., coupler size constrains), this paper would study and compare the coupler characteristics for the inductive and capacitive coupler. The uniform induced voltage source is applied for both couplers, and the influence of the coupler size parameters and resonance frequencies are evaluated and used to optimize the coupler model parameters. The peak efficiency of the different couplers and their corresponding series-series compensated systems are used to judge the coupler performance. Finally, the design constrain is proposed to show the performance boundary of inductive and capacitive coupler.

As battery-electric vehicle technology advances as a viable alternative to internal combustion engine vehicles, consumer acceptance becomes a critical factor for the future of these vehicles, with driving range and vehicle cost being the preeminent parameters of concern. Unique to battery-electric vehicles is the direct inverse relationship between these parameters. Battery pack costs often account for over one half of the vehicle cost, with the vehicle range determined by the capacity (and thus cost) of the battery pack as well. An increase in vehicle range would therefore result in a significant increase in battery pack cost, and vice versa. In addition, the relationship between overall vehicle mass and total range further inversely couples vehicle cost and range. It is apparent then that a fundamental trade-off will always exist between the two parameters, unless an additional factor is added to decouple the direct relationship between them. This paper presents results of an analytical investigation of the aforementioned relationships unique to battery-electric vehicles and proposes inductively coupled power transfer (ICPT) as a potential solution and decoupling method for the vehicle range –1 vehicle cost relationship. The proposed inductively coupled power transfer (ICPT) system was found to be very effective by allowing the battery pack size to be reduced by up to 48%.

Purpose This paper aims to present an approach to the design of the compensation networks (CNs) based on a genetic optimization algorithm. The algorithm is applied to CNs with T-topology and considers the effects of the parasitic series resistances of their inductive components. The effectiveness of the algorithm is verified using Bode diagrams and simulation results. Design/methodology/approach The paper at first describes the problem and the approach followed to reach a set of optimal solutions, then explains the optimization algorithm, reports the obtained solutions and selects the optimal CNs. Finally, the actual performance of the wireless power transfer system (WPTS) when the selected CNs are used are checked. Findings This approach gave interesting results and made available a number of different sizing solutions of complex networks in a very short time. Most of the obtained solutions outperform the widely used series-series compensation. An accurate post processing of the obtained result is mandatory to discriminate the solutions that could be implemented from those that in a real system would originate uncontrolled high frequency current oscillation. Originality/value This paper offers a rather new approach to solve the problem of sizing the CNs of a dynamic WPTS. This approach makes available a large number of optimal solutions to the problem in a short time, without solving complex system of equations.

Inductive WPT of the resonant category is generally employed for medium and high-power transmission applications like electric vehicle charging due to it contributes excellent efficiency. The high-frequency resonant full-bridge inverter using series-series resonant topology is proposed. The design of the high-frequency resonant inverter is simulated and verified by MATLAB/SIMULINK software. The charging scheme which is available in the AC-DC as well as in the DC-DC converter should operate with the two steps to achieve a duty cycle-based voltage control and hysteresis current control. The resonant frequency of the proposed system has a frequency range of 65 kHz with a DC voltage of 12V. The simulation has been carried out successfully and transmitted a 5KW power load of constant current and voltage control. The Performance chart of with the existing method is carried out in terms of parameters and the efficiency can be achieved by 95%.

Inductive power transfer (IPT) systems have become increasingly popular in recharging electric vehicle (EV) batteries. This paper presents an investigation of a series parallel/series (SP/S) resonant compensation network based IPT system for EVs with further optimized circular pads (CPs). After the further optimization, the magnetic coupling coefficient and power transfer capacity of the CPs are significantly improved. In this system, based on a series compensation network on the secondary side, the constant output voltage, utilizing a simple yet effective control method (fixed-frequency control), is realized for the receiving terminal at a settled relative position under different load conditions. In addition, with a SP compensation network on the primary side, zero voltage switching (ZVS) of the inverter is universally achieved. Simulations and experiments have been implemented to validate the favorable applicability of the modified optimization of CPs and the proposed SP/S IPT system.

A wide variety of applications can benefit from near-field wireless power transfer using coupled inductive links, such as wireless sensors and implantable microelectronic devices. The use of inductive power transmission is expected to see an explosive growth over the next decade as engineers try to cut the last cord from mobile electronics, small home appliances, and even electric vehicles [1]. The inductive link power transfer efficiency (PTE) is highly dependent of the loading of the receiver (Rx) coil, referred to as R L . As shown in Fig. 12.7.1a, magnetic resonance-based power transmission in the form of a 3-coil link has been proposed to maximize PTE for any given R L by transforming it to an optimal load, using k 34 variable [2,3]. Alternatively, an off-chip matching circuit has been used to transform R L [4]. However, these methods need either an additional coil or a network of off-chip capacitors and inductors, which add to the size/cost of Rx. Moreover, in the above applications, R L can change drastically during operation and there is a need for Rx to dynamically compensate for a wide range of R L to maintain high PTE.