In vehicle-to-grid applications, the battery charger of the electric vehicle (EV) needs to have a bidirectional power flow capability. Galvanic isolation is necessary for safety. An ac–dc bidirectional power converter with high-frequency isolation results in high power density, a key requirement for an on-board charger of an EV. Dual-active-bridge (DAB) converters are preferred in medium power and high voltage isolated dc–dc converters due to high power density and better efficiency. This paper presents a DAB-based three-phase ac–dc isolated converter with a novel modulation strategy that results in: 1) single-stage power conversion with no electrolytic capacitor, improving the reliability and power density; 2) open-loop power factor correction; 3) soft-switching of all semiconductor devices; and 4) a simple linear relationship between the control variable and the transferred active power. This paper presents a detailed analysis of the proposed operation, along with simulation results and experimental verification.

/pdf/a-bidirectional-soft-switched-dab-based-single-stage-three-28qbzd6z42.pdf

A Bidirectional Soft-Switched DAB-Based Single-Stage Three-Phase AC–DC Converter for V2G Application

In this article, a new bidirectional single-stage interleaved totem-pole electrolytic capacitorless ac–dc converter with high-frequency isolation and low components count is proposed. The proposed converter is constructed using nonregulating two-phase interleaved totem-pole converter switched with a fixed 50% duty on the grid side and a full-bridge on the dc-side for active power and dc output regulation. This switching method results in a ripple-free grid current regardless of the magnitude of the input inductances. Consequently, a proper design of input inductance secures soft switching for all switches under wide voltage and load ranges without an auxiliary circuit or resonant tank. Hence, the proposed topology overcomes the reverse recovery issue, thereby enabling the use of Si devices in CCM. Moreover, the current spike around the ac main zero-crossing is avoided in the CCM operation due to small rectified voltage around zero-crossing. Furthermore, the instantaneous powers at the grid side and dc-side are identical since the proposed topology is electrolytic capacitorless with inherent second harmonic ripple current at the dc-side. PFC is inherently performed in the proposed converter without a current shaping control loop, and the phase-shift angle is the only control variable. Hence, the control system is simple and reliable. A 3.3 kW prototype of the proposed converter is built and tested in order to verify the performance and the theoretical claims.

Interleaved Totem-Pole ZVS Converter Operating in CCM for Single-Stage Bidirectional AC–DC Conversion With High-Frequency Isolation

Mobile platforms cover a broad range of applications from small portable electric devices, drones, and robots to electric transportation, which influence the quality of modern life. The end-to-end energy systems of these platforms are moving toward more electrification. Despite their wide range of power ratings and diverse applications, the electrification of these systems shares several technical requirements. Electrified mobile energy systems have minimal or no access to the power grid, and thus, to achieve long operating time, ultrafast charging or charging during motion as well as advanced battery technologies are needed. Mobile platforms are space-, shape-, and weight-constrained, and therefore, their onboard energy technologies such as the power electronic converters and magnetic components must be compact and lightweight. These systems should also demonstrate improved efficiency and cost-effectiveness compared to traditional designs. This paper discusses some technical challenges that the industry currently faces moving toward more electrification of energy conversion systems in mobile platforms, herein referred to as E-Mobility, and reviews the recent advancements reported in literature.

/pdf/e-mobility-advancements-and-challenges-1hki7u5nil.pdf

E-Mobility — Advancements and Challenges

The rise of greenhouse gas levels in the atmosphere is a severe climate change concern. A significant part, such as CO2 emission, comes from internal combustion engine-driven vehicles, incited the automotive sector to focus more on the sustainable electric transportation system. However, electric vehicles face significant charging time, charging methods, and range anxiety challenges. To overcome these challenges, charging technologies for electric vehicle batteries play an essential role. Many types of electric vehicle charging topologies have been discussed in the literature and implemented in many practical applications. This paper presents a state of art criticism of advanced converter topologies and charging methodology for electric vehicle applications. Apart from the conventional topologies, this manuscript has covered the comparative criticism of the recently proposed EV charging technologies regarding charging methods, control strategies, and power levels. Further, this paper discussed the different onboard chargers with their power factor correction topologies, drawbacks, and required corrections. This manuscript provides the research directions for the academic and industrial communities. 

A comprehensive review on advanced charging topologies and methodologies for electric vehicle battery

The subsequent rapid increase in the Hybrid Electric Vehicles (HEVs) in the past one decade, has led to the significant intensification of one particular type of Electric Vehicles (EVs) known as Plug-in hybrid electric vehicles (PHEVs). An expeditious gain in PHEVs is due to the clean environmental considerations and secondly because of the ability of recharging its own energy storage (battery) from an off-board power sources peculiarly a grid. The most prominent issue in these vehicles is the method by which the charging of the batteries should be done and secondly the increasing demand of power required due to the rapid demand of electric power necessitated by PHEVs. This paper surveys the state of the art of existing converter topologies which is indispensable for charging the PHEVs battery charging schemes. This paper will make an attempt as an assessment to give a detailed review of different power electronic topologies used in PHEVs such as bi-directional AC-DC and DC-DC converters which fulfill these requirements. Further, an inference would be drawn by discussing the best choice of topology to be adopted for the efficient and more reliable applications in PHEVs.

A Review of Converter Topologies for Battery Charging Applications in Plug-in Hybrid Electric Vehicles

This paper proposes a novel bidirectional single-phase single-stage ac–dc converter for Electric Vehicle (EV) charging application. AC side of the proposed converter has current-fed half-bridge converter that is connected to the full-bridge converter on secondary side of a high-frequency transformer. Current at the input of the ac side can be regulated to realize power factor correction. The proposed converter achieves Zero Current Switching of primary side switches and zero current turn-ON for secondary side devices throughout the operation without any additional components. This paper also presents novel modulation technique and control algorithm to ensure soft switching throughout the operation range of the converter in both directions of power flow. Design equations are derived to help suitable selection of components for a given specification. Design of the converter, control strategy, and the results are presented for a 1.5-kVA converter for EV charger.

Novel Bidirectional Single-phase Single-Stage Isolated AC–DC Converter With PFC for Charging of Electric Vehicles

An electric system includes a local power controller and solar panel system that includes a plurality of solar modules on one or more branch circuits. A method for commissioning the electric system includes an installer using a commissioning device to send and receive information from a remote system and the local power controller performing an automatic self-test of the electric system. The results of the self-test may be packaged with photographs and measurements of the electric system and sent to a remote system where an inspector can inspect the electric system remotely. After receiving approval by the inspector, the local power controller may automatically activate each branch circuit of the electric system and thus enabling the electric system to generate electricity.

Automated commissioning and inspection for PV systems

The small signal analysis of bidirectional single-phase single-stage AC-DC converter and its application for EV charging are presented in this paper. A unique control strategy for establishing soft switching without any additional circuit is developed utilizing the traditional state-space averaging technique. The small signal model in each mode of operation is presented. Using this model, current at the input of the ac side can be regulated to realize power factor correction (PFC) and also to regulate active and reactive power flow in either direction. Four quadrant operation of the converter can be utilized for improving the stability of the power grid. Controller designed using the derived small signal model is used to validate the operation as well as transition of the converter between V2G and G2V modes. Simulation results are presented to demonstrate four quadrant operation of the designed converter. Design of the converter, closed loop controller, and the results are presented for 1.5kVA converter.

Modelling and Control of Novel Bidirectional Single-Phase Single-Stage Isolated AC-DC Converter with PFC for Charging of Electric Vehicles

Torque smoothness is an essential requirement for high-performance motor drive applications. Synchronous reluctance machines have high torque ripple due to non-linear magnetic path coupled with saturation of the rotor core segments during operation. This paper proposes an active torque ripple minimization technique for Synchronous reluctance machine using current injection. The proposed method is aimed to compensate for both cogging and torque ripple generated by the machine. The method also optimizes for the minimum magnitude of ripple injection for active cancellation. The effectiveness of the proposed method is evaluated with both simulation and experimental results.

Torque Ripple Minimization Control Strategy in Synchronous Reluctance Machines

This paper discusses the effect of the position measurement delay on the performance a Permanent Magnet Synchronous Motor (PMSM) drive. The delays occurring in the measurement of the signals required for the control are usually neglected. This paper, explicitly focuses on the effect of position error due to delays in the measurement. The accurate prediction and compensation of position measurement delay is required to achieve the optimum performance of electrical machines. The performance is evaluated in terms of the average torque output under a given current command condition. A mathematical model of the average torque output with the various position delay usually present in practical system, is presented. Experimental results are provided showing the effect of such position delay and the improvement obtained after compensating for such delays. The knowledge of the measurement delay could be used to optimize the control implementation methods. The ignorance of such small delays could cause significant negative impact in high speed electric drives.

Anant Kumar Singh

Papers

Novel Bidirectional Single-phase Single-Stage Isolated AC–DC Converter With PFC for Charging of Electric Vehicles

Automated commissioning and inspection for PV systems

Modelling and Control of Novel Bidirectional Single-Phase Single-Stage Isolated AC-DC Converter with PFC for Charging of Electric Vehicles

Torque Ripple Minimization Control Strategy in Synchronous Reluctance Machines

Effect of Position Measurement Delay on the Performance of PMSM Drive