Wide Input Voltage Operation Research Articles

Analysis of a Resonant Converter with Wide Input Voltage

A DC-DC converter with a 16:1 (Vin,max = 16Vin,min) wide input voltage operation is presented for auxiliary power supplies on solar power conversion circuits or railway vehicles. The solar cell output voltage is associated with the solar intensity (day or night) and geographical location. Thus, the wide input voltage capability of DC converters is required for photovoltaic power conversion. For low power supplies on railway vehicles, the nominal input voltages are 24 V~110 V for the electric door system, motor drive, solid state lighting systems and braking systems. The presented converter uses buck/boost and resonant circuits to achieve the wide input voltage range operation from 18 V to 288 V. If Vin stays on a low input voltage range (18 V~72 V), the buck/boost circuit is operated at a voltage boost characteristic. On the other hand, the buck/boost circuit is operated at a voltage buck characteristic when the input voltage climbs to a high voltage range (72 V~288 V). Thus, the buck/boost circuit can output a constant voltage. Then, the resonant circuit in the second stage is worked at a constant input voltage case so that the frequency variation range is reduced. Finally, to investigate the performance and effectiveness of the studied circuit, experiments with a 500 W prototype were conducted to investigate the performance of the studied circuit.

Stand‐alone PV water pumping system based on high‐gain resonant inverter fed induction motor serving two‐head for permanent water supply

SummaryA vast community of developing countries, like India, is still deprived of a proper water supply system. Such communities often depend on hand‐pumps, ponds, and ravines for their daily water needs. Government‐subsidized PV‐based water pumps have emerged as a boon for such communities. But intermittent nature of solar irradiation and unavailability at night time poses a big challenge. To mitigate this challenge, the present article proposes a stand‐alone PV‐based induction motor‐driven water pumping system serving a dual‐head, that is, an overhead storage tank and ground level supply. A single‐stage three‐phase high‐gain resonant inverter (HGRI) is proposed for driving the induction motor. A back‐ended wide bandgap (WBG) device‐based boost converter is used to extract maximum power from PV by employing the MPPT algorithm. HGRI injects sinusoidal current to the induction motor while operating it through PV power matched modified V/f control algorithm, thus minimizing the torque ripple. HGRI coupled with boost converter provides a high‐gain voltage boost at the output; enabling wide input voltage operation, which increases the operability of the system in high as well as low irradiation level. The practicality of the system is validated on a laboratory‐developed hardware test bed with a 1.5HP induction motor.

Analysis of a Wide Voltage Hybrid Soft Switching Converter

A hybrid PWM converter is proposed and investigated to realize the benefits of wide zero-voltage switching (ZVS) operation, wide voltage input operation, and low circulating current for direct current (DC) wind power conversion and solar PV power conversion applications. Compared to the drawbacks of high freewheeling current and hard switching operation of active devices at the lagging-leg of conventional full bridge PWM converter, a three-leg PWM converter is studied to have wide input-voltage operation (120–600 V). For low input-voltage condition (120–270 V), two-leg full bridge converter with lower transformer turns ratio is activated to control load voltage. For high input-voltage case (270–600 V), PWM converter with higher transformer turns ratio is operated to regulate load voltage. The LLC resonant converter is connecting to the lagging-leg switches in order to achieve wide load range of soft switching turn-on operation. The high conduction losses at the freewheeling state on conventional full bridge converter are overcome by connecting the output voltage of resonant converter to the output rectified terminal of full bridge converter. Hence, a 5:1 (600–120 V) hybrid converter is realized to have less circulating current loss, wide input-voltage operation and wide soft switching characteristics. An 800 W prototype is set up and tested to validate the converter effectiveness.

Hybrid LLC Converter with Wide Range of Zero-Voltage Switching and Wide Input Voltage Operation

A new hybrid inductor-inductor-capacitor (LLC) converter is investigated to have wide voltage input operation capability and zero-voltage turn-on characteristics. The presented circuit topology can be applied for consumer power units without power factor correction or with long hold-up time requirement, photovoltaic energy conversion and renewable energy power transfer. To overcome the weakness of narrow voltage gain of resonant converter, the hybrid LLC converter with different turns ratio of transformer is presented and the experimental investigation is provided to achieve wide voltage input capability (400 V–50 V). On the input-side, the converter can operate as full bridge resonant circuit or half bridge resonant circuit with input split capacitors for high or low voltage input region. On the output-side, the less or more winding turns is selected to overcome wide voltage input operation. According to the circuit structures and transformer turns ratio, the single stage LLC converter with wide voltage input operation capability (400 V–50 V) is accomplished. The laboratory prototype has been developed and the experimental waveforms are measured and demonstrated to investigate the effectiveness of the presented hybrid LLC converter.

Implementation of a Wide Input Voltage Resonant Converter with Voltage Doubler Rectifier Topology

A new circuit structure of LLC converter is studied and implemented to achieve wide zero-voltage switching range and wide voltage operation such as consumer power units without power factor correction and long hold up time demand, battery chargers, photovoltaic converters and renewable power electronic converters. The dc converter with the different secondary winding turns is adopted and investigated to achieve the wide input voltage operation (50–400 V). To meet wide voltage operation, the full bridge and half bridge dc/dc converters with different secondary turns can be selected in the presented circuit to have three different voltage gains. According to input voltage range, the variable frequency scheme is employed to have the variable voltage gain to overcome the wide input voltage operation. Therefore, the wide soft switching load variation and wide voltage operation range are achieved in the presented resonant circuit. The prototype circuit is built and tested and the experiments are demonstrated to investigate the circuit performance.

Resonant converter with less voltage rating of power switches and wide voltage operation

A resonant converter with less voltage rating of power switches and wide voltage operation is investigated in this Letter for medium voltage applications. Four active switches and two split capacitors are adopted on the primary side to reduce the voltage rating on power semiconductors. The resonant converter is adopted in the converter to have a wide soft switching operation range. Two flying capacitors are used in the presented circuit to operate as the resonant capacitor and also to achieve voltage balance of two input split capacitors. The variable winding turns are used on the secondary side to overcome the problem of the limited voltage operation in the conventional resonant converter. If the input voltage is in the low-input voltage range, the low turns-ratio of the power transformer is used to increase the voltage gain of the resonant converter. If the input voltage is in a high-voltage range, then the high turns-ratio of the transformer is adopted to reduce the voltage gain. Thus, the proposed converter can achieve wide input voltage operation. Experimental results with a 0.8 kW prototype are provided to confirm the effectiveness of wide input voltage operation from 260 to 800 V.

Wide load

Researchers working at the National Yunlin University of Science and Technology in Taiwan present a new resonant converter. The converter has two advantages; firstly, it uses two flying capacitors to balance input split voltages and secondly, it has a wide input-voltage range of operation, along with variable secondary winding turns, due to use of an AC switch. Resonant converters are power electronics devices containing a network of inductors and capacitors known as a ‘resonant tank’. They can be tuned to resonate at specific frequencies and find a multitude of applications in electronics as parts of integrated circuits. Power converters for medium and high voltage applications are widely used for reactive power control and in AC motor-drives. Whilst full-bridge converters are excellent for high-voltage uses, the materials used to produce them (silicon carbide or gallium nitride) are very expensive, and so it is more economically efficient to use cheaper devices and optimise their performance. Circuit diagram of the proposed device. Experimental waveforms of the proposed converter. a Vin, VCin1, VCin2 at Vin = 260 V and the rated power b Vin, VCin1, VCin2 at Vin = 800 V and the rated power c iD1, iD2, Vo, Io at Vin = 260 V and the rated power d iD3, iD4, Vo, Io at Vin = 800 V and the rated power As we move to more renewable energy sources, such as solar and wind power, we find that the voltage output of harvesting devices, such as solar panels and wind turbines, fluctuates over time. Due to this fluctuation, it is important that power electronics used to transfer the energy from these devices are equipped to deal with a range of voltages. The basic circuit topology for these applications is a two-stage power converter. An alternative topology is a series or parallel connection of full bridge converters. Both topologies have drawbacks however, two-stage converters suffer from low circuit efficiency, whilst series/parallel full bridge converters require a large number of circuit components and also introduce additional power losses. The device presented in this issue of Electronics Letters boasts zero-voltage switching on active devices and a wide input-voltage operation range, between 260 and 800 V. The proposed device comprises a two-part circuit. Input voltage is provided by a unstable input, such as a solar panel or wind turbine device. Two split capacitors and two half bridge legs are included on the input-side of the circuit to reduce the voltage rating on the 4 power switches. Power MOSFETS (metal-oxide-semiconductor field-effect transistors) in the circuit are able to withstand ∼800 V of input voltage. The other side of the converter is a voltage double rectifier, effectively doubling the output voltage. Different parts of the second half of the converter are active depending on the voltage coming across from the input-half of the converter, ensuring that the converter is working optimally across the input-voltage range. Frequency modulation is adopted in the converter to control load voltage and to generate pulse-width modulation (PWM) signals of active devices. Experimental verification of the converter is provided by the authors. It can be seen that the device clearly performs well across the wide input range of 260–800 V. The two split capacitor voltages are well balanced, showing the device is stable. As the device does not rely on expensive semiconductor materials such as silicon carbide or gallium nitride, the device is more economically viable for mass production. This device is promising as a candidate for resonant converter applications such as renewable energy conversion, especially for renewable energy sources with unstable voltage outputs (such as solar and wind power). Future experiments could look at the feasibility of improving the input voltage range of the device even further, or further improving the amount by which the input voltage is increased post-conversion.

Analysis and Verification of a Wide Input Voltage PWM Converter with Variable Windings

A three-leg pulse-width modulation converter with auxiliary windings is provided and investigated to realize wide voltage operation and zero voltage switching characteristics on power switches. The presented converter has three converter legs on the input-side and two sets of winding turns on the output-side. Owing to the on/off states of the three converter legs and the two sets of secondary winding turns, the proposed converter can be operated under three different equivalent circuits to have wide input voltage operation from 30V ~ 240V (Vin,max = 8Vin,min). Compared with the multi-stage converters to realize wide input voltage operation, the proposed circuit topology has fewer circuit components and a simple control algorithm. Conventional duty cycle control with phase-shift between each converter leg is adopted to regulate load voltage and also accomplish zero voltage switching on active switches. The presented three-leg converter is tested with a laboratory circuit. Finally, experiments testify to the performance and validity of the presented converter.

Analysis and Implementation of a Phase-Shift Pulse-Width Modulation Converter with Auxiliary Winding Turns

A phase-shift pulse-width modulation converter is studied and investigated for railway vehicle or solar cell power converter applications with wide voltage operation. For railway vehicle applications, input voltage range of dc converters is requested to have 30–40% voltage variation of the nominal input voltage. The nominal input voltages of dc converters on railway vehicles applications may be 37.5 V, 48 V, 72 V, 96 V and 110 V. Therefore, a new dc converter with wide input voltage operation from 25 to 150 V is presented to withstand different nominal input voltage levels such as 37.5–110 V on railway power units. To realize wide input voltage operation, an auxiliary switch and auxiliary transformer windings are used on output side of conventional full-bridge converter to have different voltage gains under different input voltage values. Phase-shift pulse-width modulation is adopted in the developed dc converter to accomplish soft switching operation on power switches. To confirm and validate the practicability of the presented converter, experiments based on a 300 W prototype were provided in this paper.

Hybrid Resonant Converter with Three Half-Bridge Legs for Wide Voltage Operation

This paper studied a hybrid resonant converter with three half bridge legs for wide input voltage operation. Compared to the conventional resonant converters with narrow voltage operation, the presented converter can achieve wider voltage operation. On the basis of the proper switching status of power switches, the developed converter can operate at half-bridge resonant circuit under high input voltage range and the other two full-bridge resonant circuits under medium and low input voltage ranges. Each resonant circuit has a 2:1 (Vin,max = 2Vin,min) input voltage operation range. Therefore, the developed converter can achieve an 8:1 (Vin,max = 8Vin,min) wide voltage operation. The main advantage of the studied converter is the single-stage direct current (DC)/DC power conversion instead of the two-stage power conversion to achieve wide voltage operation. Because the equivalent resonant tank of the adopted converter is controlled by frequency modulation, the soft switching operation on power switches or rectifier diodes can be realized to improve circuit efficiency. The performance of the proposed circuit was confirmed and verified by experiments with a laboratory circuit.

Phase-Shift PWM Converter with Wide Voltage Operation Capability

A soft switching three-level pulse-width modulation (PWM) converter is presented for industrial electronics with wide voltage range operation, such as solar power or fuel cell applications. Phase shift PWM scheme is used on the input-side to accomplish the zero voltage turn-on on power switches and improve the converter efficiency. Three-level diode-clamp circuit topology is adopted in the presented circuit to lessen the voltage ratings on active devices for high voltage applications. Three sub-circuits with the different turns-ratio of transformers can be selected in the presented converter in order to achieve 10:1 (Vin,max = 10Vin,min) wide input voltage operation when compared to the conventional multilevel converter. The proposed circuit is a single-stage converter instead of two-stage converter to realize wide voltage operation. Therefore, the presented converter has less component counts. Finally, the design procedure and experiments with a 300W laboratory circuit are presented and discussed to confirm the circuit analysis and converter performance.

Implementation of a Parallel-Series Resonant Converter with Wide Input Voltage Range

A new resonant converter is presented to have the advantages of soft switching operation on power devices, without reverse recovery current loss on power diodes and wide input voltage range operation. Resonant converter with frequency modulation is adopted in the proposed circuit to accomplish the low switching loss on power switches and possible zero current switching operation on fast recovery diodes. To improve the problem of limit voltage range operation in the conventional resonant converter, a new parallel-series structure resonant converter is studied to achieve wide input voltage operation capability, such as from Vin,min to 4Vin,min. A 1.8 kW laboratory circuit is implemented, and the measured results are provided to confirm the theoretical analysis and circuit performance.

Resonant converter with wide input voltage range and input current ripple‐free

A current fed resonant converter is presented and developed to have the advantages of wide input voltage operation range and less ripple current. The developed circuit includes two boost inverters in the front stage and one resonant converter in the rear stage. Two boost converters are operated using interleave pulse-width modulation in order to reduce the input ripple current. The resonant converter with voltage doubler circuit topology is adopted to obtain high-voltage output and realise zero-voltage turn-on switching for all power switches over all load ranges. The active switches of two boost converters and the resonant converter share the same power switches so that the switch counts in the studied circuit are reduced. In order to extend the input voltage operation range, an additional boost converter is active when the input voltage is lower than the defined voltage level. Therefore, a wide input voltage range operation, 24–76 V, of the developed circuit can be realised to apply in the fuel cells or solar cells input applications. The feasibility and practicality of the developed circuit are confirmed by the test results with an 800 W prototype circuit.