A two-input boost converter with voltage multiplier cell is proposed in this paper. Then a family of two-input converters with and without voltage multiplier cell are derived and their results are compared to achieve high voltage gain, low duty cycle, and reduced voltage stress. From the analysis of different topologies, a modified two-input converter with two-stage voltage multiplier cell has good operating characteristics. The switch voltage stress and duty cycle of the modified converter is significantly very less than that of the other converter topologies. The modified DC-DC converter with 50% duty cycle achieves a voltage gain of 10 and the results are verified by using MATLAB/Simulink software.
Boost converter with high gain finds applications in various renewable energy sources such as solar energy systems, fuel cell systems and also in electric vehicles. Mostly two types of DC-DC converters are present and they are: transformer less (isolated DC-DC converter) and with transformer (non-isolated DC-DC converter) [
The size and efficiency of the power transformer is a major constraint of the isolated DC-DC converters. Some non-isolated DC-DC converters such as boost can provide increased voltage gain but the voltage, current stress and duty cycle are high [
The proposed modified two-input converter has high step-up voltage gain with reduced component count, reduced voltage stress across the switches and diodes which in turn reduce both switching and conduction losses. The voltage and current stress of the devices are also less because of low duty cycle.
This paper is organized as follows. The generation of the new converter family is presented in Section 2, and the principle of operation is also given. An extension of the new topology to other topologies is also presented in Section 2. The simulation results are presented in Section 3. The comparison of different topologies is presented in Section 4 and the conclusion is given in Section 5.
The two-input boost converter without voltage multiplier cell is shown in
A. First Operation Mode: In Mode 1, the switch S1 & S2 are turned ON. So the input voltage vin1 charges the input inductor L1 and input voltage vin2 charges the input inductor L2. Due to this, there is no conduction in diodes D1, D2.So that the load is isolated from the input.
B. Second Operation Mode: In Mode 2 Operation, the switch S1 & S2 are turned OFF. So the diodes come to conduction and the input inductors current flows through diode D1 & D2 and capacitance C01 & C02 to load so the capacitors C01 & C02 gets charging. When the switches are OFF, current in the diodes is reduced to zero. So the diode D1 & D2 is blocked. It will minimize diode reverse recovery current also with low di/dt. So that capacitors are discharges the energy to load.
The two-input boost converter with voltage multiplier cell is shown in
A. First Operation Mode: When the switches S1 & S2 are turned OFF, the energy stored in the input inductor Lin1 & Lin2 will be transferred to the multiplier capacitor CM1 & CM2 through the diodes DM1 & DM2 respectively. The resonant inductor current (Lr1 & Lr2) rise linearly from zero to the maximum value of the input inductor currents (ILin1 & ILin2) and the current in the diode DM1 & DM3 is reduced at same proportion.
B. Second Operation Mode: At the instant (t1), the current in the diode DM1 & DM3 is zero and this diode is blocked with low di/dt, minimizing the diode reverse recovery current. The resonant inductor current is same as the input inductor current during this stage and the energy stored in the input inductor is transferred to the load through the diodes Do1 & Do2.
C. Third Operation Mode: At time instant (t2), the switches S1 & S2 are turned-on with zero current and the current in the resonant inductor Lr1 & Lr2 and in the output diode D01 & D02 reduces linearly until zero, at time instant (t3). Thus the reverse recovery current of the output diode is also minimized.
D. Fourth Operation Mode: When output diode is blocked, DM2 & DM4 conducts and transfers part of the energy stored in the capacitors CM1 to CM2 and CM3 to CM4. When there is a balance of energy between the multiplier capacitors, the diode DM2 & DM4 are blocked (t4) also with low di/dt. During the switch turn-on the input inductor stores energy as the classical boost.
The two-input boost converter with and without voltage multiplier cell is shown in
A. First Operation Mode: In this mode S1 is turned ON and S2 is turned OFF. The input voltage charges the input inductor Lin1 and energy stored in the inductor Lin2 is transferred to CM1 through the diode DM1. The resonant inductor current (ILr) rises linearly from zero until to reach the value of the input inductor current (ILin1) and the current in the diode DM1 is reduced at same the quantity. The resonant inductor current which in turn charges the output capacitor Co through the diode D0.
B. Second Operation Mode: In this mode S1 is turned OFF and S2 is turned OFF. The current in the diode DM1 is zero and this diode is blocked with low di/dt, minimizing the diode reverse recovery current. The resonant inductor current is same as the input inductor current and the energy of the input inductor is transferred to
the load through the diode Do.
C. Third Operation Mode: In this mode switches S1 and S2 are turned ON and the resonant inductor Lr and the output diode Do current reduces linearly to zero. Thus the reverse recovery current of the output diode is also minimized.
D. Fourth Operation Mode: In this mode S1 is turned ON and S2 is turned ON, when output diode is blocked, DM2 conducts transferring part of the energy stored in the capacitor CM1 to the capacitor CM2 in resonant way. When there is a balance of energy between the multiplier capacitors, the diode DM2 is blocked (t4) also with low di/dt. During the switch turn on the input inductor stores some energy as the classical boost.
The modified two-input boost converter with voltage multiplier cell is shown in
A. First Operation Mode 1: In this mode both switches S1 and S2 are ON. Both the inductors are charged from their input sources Vin1 and Vin2. The current in both the inductors rise linearly. The diodes in different VM stages are reverse biased and do not conduct. The VM capacitor voltages remain unchanged and the output diode Do is reverse biased. Thus the load is supplied by the output capacitor Co.
B. Second Operation Mode 2: In this mode switch S1 is OFF and S2 is ON. All the odd numbered diodes are forward biased and the inductor current ILin1 flows through the voltage multiplier capacitors charging the capa-
citors (C2, C5) and discharging the capacitors (C1, C4). If the number of VM stages is odd, then the output diode Do is reverse biased and the load is supplied by the output capacitor. However, if the number of VM stages is even, then the output diode is forward biased charging the output capacitor and supplying the load. In the particular case considered here, since there are four VM stages, the output diode is forward biased.
C. Third Operation Mode: In this mode switches S1 and S2 are turned ON and resonant inductor Lr and the output diode Do current reduce linearly to zero. Thus the reverse recovery current of the output diode is also minimized.
D. Fourth Operation Mode: In this mode S1 and S2 are turned OFF, when output diode is blocked, DM2 conducts and transfers the energy stored in the capacitor CM1 to CM2. When there is a balance of energy between the multiplier capacitors, the diode DM2 is blocked (t4) also with low di/dt. During the switch turn on the input inductor stores some energy as the classical boost.
The simulation of the converters with & without voltage multiplier cell is done by using the MATLAB/Simulink tool and the results are analyzed.
The output voltage and output current waveform of Proposed Two-Input Boost Converter without Voltage Multiplier Cell/Proposed Two-Input Voltage Multiplier Cell with Voltage Multiplier Cell/Proposed Two-Input Boost Converter with Voltage Multiplier Cell/Modified Two-Input Boost Converter with Voltage Multiplier Cell are given in Figures 5(a)-(d). The output voltage waveform of modified converter was well settled at 136.5 V. There exists less overshoots before settling the voltage waveform and the output voltage waveform is less from ripples. The voltage across the switches of Modified Two-Input Boost Converter with Voltage Multiplier Cell is given in
The
The principle of operation and analysis of different converters with modified DC-DC converter are presented in this paper. The high voltage gain with low duty cycle is achieved for the modified topology. The modified converter significantly minimizes the voltage stress in the two active diodes and switches with high voltage gain. This approach will lead to reduce switching and conduction losses and also to select MOSFET and diodes with lower voltage rating respectively. Furthermore, the topology explores the way to eliminate the usage of additional circuitry, complex control and also guide to uniform current sharing. From the analysis and comparison of results, the high step-up voltage gain with low duty cycle and reduced switch voltage stress modified converter is ap-
Type of converter | Parameters value | Input voltage (V) | Duty cycle (Sec) | Input current stress (A) | Voltage across switch (V) | Output voltage gain (V) | Output current(A) | output power (W) | Peak overshoot (%) |
---|---|---|---|---|---|---|---|---|---|
Single input boost converter | L = 1.15 mH, C = 483 µF, Ro = 100 Ω | Vin = 12 V | D = 0.90 | Iin = 13 A | Vsw = 111.3 V | Vo = 110.5 V | Io = 1.105 A | Pout = 122 W | 29.86% |
Proposed two input boost converter without VMC | Lin1 = Lin2 = 1.64 mH, Co1 = Co2 = 241.7 µF, Cm = 21 µF, Ro1 = Ro2 = 100 Ω | Vin1 = 12 V, Vin2 = 12 V | D1 = 0.90, D2 = 0.90 | Iin1 = 7.25 A Iin2 = 7.25 A | Vsw1 = 116.1 V Vsw2 = 116.1 V | Vo = 115.3 V | Io = 1.153 A | Pout = 132.9 W | 45.7% |
Proposed two input VMC with VMC converter | Lin1 = Lin2 = 0.665 mH, Co1 = Co2 = 29.86 µF, Cm = 21 µF, Ro1 = Ro2 = 100 Ω | Vin1 = 12 V, Vin2 = 12 V | D1 = 0.82, D2 = 0.82 | Iin1 = 9.6 A Iin2 = 9.6 A | Vsw1 = 61 V Vsw2 = 61 V | Vo = 121.7 V | Io = 1.217 A | Pout = 148 W | 24% |
Proposed two input boost converter with VMC | Lin1 = 1.64 mH, Lin2 = 0.665 mH, Co1 = 241.7 µF, Co2 = 29.86 µF, Cm = 21 µF, Ro1 = Ro2 = 100 Ω | Vin1 = 12 V, Vin2 = 12 V | D1 = 0.90 D2 = 082 | Iin1 = 6 A Iin2 = 11 A | Vsw1 = 117.3 V Vsw2 = 58.03 V | Vo = 116.5 V | Io = 1.165 A | Pout = 135.7 W | 26.14% |
Modified two input boost converter with VMC | Lin1 = 0.571 mH, Lin2 = 0.571 mH, Co1 = 50 µF, Co2 = 50 µF, Cm = 47 µF, Ro = 100 Ω | Vin1 = 12 V, Vin2 = 12 V | D1 = 0.5 D2 = 0.6 | Iin1 = 8.2 A Iin2 = 7.9 A | Vsw1 = 25 V Vsw2 = 25 V | Vo = 116.5 V | Io = 1.165 A | Pout = 135.7 W | 20% |
propriate one for multi-input source applications.
L. Chitra,M. Karpagam,K. Saranyadevi, (2016) Proposal of High Gain, Reduced Stress with Low-Duty-Cycle Two-Input Boost Converter for Renewable Energy Systems. Circuits and Systems,07,489-496. doi: 10.4236/cs.2016.74041