High‐efficiency duty‐cycle controlled full‐bridge converter for ultracapacitor chargers

The light rail vehicles (commonly known as tramways or lightly laid railways) offer environmental advantages and have evoked an impressive attraction. The hybrid energy-storage systems efficiently supply energy for the light rail vehicles during the travel. This study implements and analyses an ultracapacitor charger in hybrid energy-storage system for electricvehicle applications. Moreover, an ultracapacitor charger based on a full-bridge DC-DC converter that utilises a synchronousrectification technique and high charging-current capability is presented. The proposed converter's current-doubler synchronous rectification reduces the secondary circulating current and recycles the energy of the leakage current to the power-source lead to further increase conversion efficiency. A prototype of this ultracapacitor charger, with an input voltage of 380 V and an output voltage of 14.6 V, has been implemented; the measured efficiency is 92.1% at a full load of 1 kW. In addition, the experimental results show the highest efficiency is 93.4% at an output power of 600 W. Furthermore, an ultracapacitor of 250 F is charged by the presented converter with a charging current of 65 A, and experimental waveforms illustrate that the charging time of the ultracapacitor voltage from 0 to 14.6 V is within 1 min.

Section: Introductionmentioning

confidence: 99%

Implementation and analysis of ultracapacitor charger in hybrid energy‐storage system for electric‐vehicle applications

Tseng

Chang

Cheng

2020

“…Furthermore, the isolated converters can handle multi-output with different voltage value. Five main isolated DC/DC converters are as follows: the flyback [5][6][7][8][9][10][11], forward [12][13][14], push-pull [15], half-bridge [16], and full-bridge converters [17][18][19][20][21][22]. The manufacturing cost, the power transfer capability and the rated voltage and current of the desired converter usually limit our selection between the above topologies.…”

Section: Introductionmentioning

confidence: 99%

Design, modelling, and implementation of a modified double‐switch flyback‐forward converter for low power applications

Eshkevari¹,

Mosallanejad

Sepasian

2019

This study proposes a modified double-switch flyback-forward (DSFF) converter for low-power applications with a reduced number of windings in its transformer. This circuit has resulted from the combination of the two-switch flyback and twoswitch forward converters. It includes a simple transformer with one set of secondary side windings, and it is not necessary to design two separate sets of windings for the desired output voltage which is the main problem of other flyback-forward converters. An auxiliary winding has been designed for self-biasing, and consequently, it improves the overall efficiency in the no-load condition. Due to the modifications on the previously presented two-switch flyback-forward converter, the circuit model has changed. This study, first, analyses the operation of the proposed converter in detail, then it explains a method to design this converter in continuous inductor current mode. Also, a start-up voltage regulator circuit and a modified bootstrap gate driver will be investigated, and the DC and AC model of the converter will be presented. Experimental results validate the proposed DSFF converter. The tested circuit includes a DSFF converter, a pulse generator circuit, a start-up voltage regulator, and a modified bootstrap gate driver.

“…Electric drives based on ultracapacitor have been investigated intensively in recent years [1][2][3][4]. The reason for this lies in the outstanding features of the ultracapacitor: the ability of regenerative energy storage and instantaneous high-power discharge characteristic.…”

Section: Introductionmentioning

confidence: 99%

Controllable regenerative braking process for hybrid battery–ultracapacitor electric drive systems

Peng

Wang

Shen

et al. 2018

This study proposes a controllable regenerative braking process for hybrid battery-ultracapacitor electric drive systems. The motor in the system is controlled to brake with a constant torque. To this end, a control framework is proposed which includes a circuit topology, decentralised active disturbance rejection controllers (ADRCs) and an operational modes switch controller (OMSC). The motor brakes with ultracapacitor when its speed is fast, and brakes with a dissipative resistor when its speed is slow. Decentralised ADRCs guarantee that ultracapacitor-based braking mode and dissipative resistor-based braking mode can be controlled individually. OMSC coordinates the decentralised ADRCs working cooperatively. Modified ADRC is proposed to implement bumpless transfer when the operational mode or braking mode is switched. The advantages of the proposed control system are as follows: (i) the control of the regenerative braking process based on ultracapacitor and dissipative resistor is linked with the control of the motor; (ii) speed of the motor in the electric drive system is controllable during the regenerative braking process; and (iii) bumpless transfer is guaranteed when braking mode changes from ultracapacitorbased braking mode to dissipative resistor-based braking mode. The following experimental results validate the proposed control framework for the controllable regenerative braking process.