0018-9545 (c) 2018 IEEE. Personal use is permitted, but republication/redistribution requires IEEE permission. See http://www.ieee.org/publications_standards/publications/rights/index.html for more information. This article has been accepted for publication in a future issue of this journal, but has not been fully edited. Content may change prior to final publication. Citation information: DOI 10.1109/TVT.2019.2897118, IEEE Transactions on Vehicular Technology Copyright (c) 2015 IEEE. Personal use of this material is permitted. However, permission to use this material for any other purposes must be obtained from the IEEE by sending a request to pubs-permissions@ieee.org. 1 Power Factor Improvement in Modified Bridgeless Landsman Converter Fed EV Battery Charger Radha Kushwaha, Member, IEEE and Bhim Singh, Fellow, IEEE Abstract- This work deals with the design and implementation of a new charger for battery operated electric vehicle (BEV) with power factor improvement at the front- end. In the proposed configuration, the conventional diode converter at the source end of existing electric vehicle (EV) battery charger, is eliminated with modified Landsman power factor correction (PFC) converter. The PFC converter is cascaded to a flyback isolated converter, which yields the EV battery control to charge it, first in constant current mode then switching to constant voltage mode. The proposed PFC converter is controlled using single sensed entity to achieve the robust regulation of DC-link voltage as well as to ensure the unity power factor operation. The proposed topology offers improved power quality, low device stress, low input and output current ripple with low input current harmonics when compared to the conventional one. Moreover, to demonstrate the conformity of proposed charger to an IEC 61000-3-2 standard, a prototype is built and tested to charge a 48V EV battery of 100Ah capacity, under transients in input voltage. The performance of the charger is found satisfactory for all the cases. Keywords— Battery Operated Electric Vehicle; Battery Charger; Power Factor Improvement; Modified Landsman Converter; Power Quality I. INTRODUCTION With the strict supervision on emissions, fuel savings, global warming issues and limited energy resources, the contribution of electric mobility is significant towards the development of sustainable and efficient alternative in the transport sector [1-2]. Regarding this, a survey based on the present scenario and future technologies for the propulsion of electric vehicle (EV), are presented in [3]. The electric mobility provides several advantages over the conventional petrol and diesel powered vehicles. However, to incorporate the transportation electrification thoroughly, deep attention of the researcher is required. Certain efficacious control strategies need to be developed to integrate them with the existing distribution system. Some of the above mentioned strategies are correlated with the power quality issues addressed by the EV chargers that associate with the charging process of battery packs [4-5]. The EVs are powered up by the rechargeable batteries to provide the necessary traction force. These batteries are typically recharged using an AC–DC converter known as an EV charger. The most general architecture of EV battery charger, comprises a boost converter at front-end and an isolated converter at the next stage [6]. The performance characteristic of this kind of charger, is exclusively decided by the performance of the DC-DC converter due to regulated output voltage and output current. Several interleaved and zero voltage switching (ZVS) PFC (Power Factor Correction) converter based battery chargers are reported in [7-10], which reduce the inductor size and output current ripple. However, interleaving the PFC converter comes with the cost of high current stress in switches. The full-bridge topology is the prominent for PFC based EV chargers with the advantages like high power density and high efficiency but the arrangement of four switches, makes the charger control complex [11]. An LLC (Inductor–Inductor–Capacitor) resonant converter offers an attractive solution with high efficiency, low EMI (Electromagnetic Interference) noise and a high power density at wide input range [12-13]. However, due to added difficulty in design and analysis process of LLC converter, this type of topology is being substituted by unidirectional or bidirectional AC-DC converters in integrated on-board or off-board configurations [14]. Considering AC-DC conversion as the distinguished feature of EV battery chargers, many DBR (Diode Bridge Rectifier) fed unidirectional isolated single stage or two- stage converters without isolation, are identified in [15]. In this context, Fig.1 (a) shows the configuration of a classical single phase DBR fed unidirectional E-rickshaw battery chargers. The corresponding specification of E- rickshaw under observation, is also given in Table-I, which battery is used as load to show the power quality performance of conventional DBR fed charger. However, the performance of the conventional charger do not match with the prescribed power quality (PQ) standard IEC 61000-3-2 [16], as shown in Fig.1 (b). The presence of full-wave diode bridge at the input of the charger, generates a large amount of harmonics distortion (55.3%) in the input current drawn during the process of battery charging. This makes the source power factor poor. Moreover, the input current shape is no more sinusoidal, resulting in an increase in displacement between source voltage and current. Therefore, an efficient power factor correction (PFC) technique, which eliminates the adverse effects of input DBR as well, is needed at the front-end of the conventional DBR fed charger. + - Lac DBR Flyback Converter Vdc vs Sf Cdc Idc Cac D Co - Control unit-2 PWM generator Current controller Voltage controller + - Sawtooth generator + EMI Filter Cac Vdc * Vdc Idc Idc * (a) (b) Fig. 1 Conventional E-Rickshaw Battery Charger: (a) Configuration (b) Measured input current, input power and THD in input current