Design and Simulation of a High Gain Boost Converter with Reduced Input Current Ripple

Abstract

This paper proposes a high gain novel DC- DC converter. According to this topology gain of the converter can be improved more than a boost converter without using any transformer. In this topology it is possible to increases the gain of the converter without increasing the current ripple in the input current. This proposed topology is capable to reduce the voltage stress of the switches. Implementation of non-isolated topology eliminates the need of the transformer and reduces the magnetic size. The maximum duty restriction problem can be reduced by the higher gain of this proposed converter. The ripple reduction in the input current increases the life of energy storage system.

Introduction

I. INTRODUCTION

For the past few years energy demand is increasing rapidly which has a major impact on the storage of energy. Though the energy demand is increasing day by day the storage of fossil fuel is decreasing with time.  In this current scenario the focus on renewable energy is more concentrated. Another benefit of renewable energy is that it maintains the cleanliness of the environment. For electrical energy generation Photovoltaic system are gaining popularity [4]. In small power generating units the generated voltage is comparatively much lower than the voltage required to consume by the load. [2] To operate the load from this source a converter is needed which will boost the voltage. In low and medium power range a battery storage system is sometimes used as a energy storage system with the PV. Most of the cases 48V batteries are used [1]. To supply load 110V AC a bus voltage magnitude of 155V is needed. For the pulse width modulation control bus voltage is needed be increased upto 200V DC. With lower bus voltage, transformer is used in output side of the transformer to increase the output voltage level and provide isolation. Transformers connected in the output side of the inverter generally operates in low frequency which increases the magnetics size and thus increases the total size of the power converter. Low voltage DC supply can be boosted up by using a boost converter which can reduce the magnetics size because they operate at higher frequency. A conventional boost converter is not sufficient for higher voltage boosting application. The major problem associated with the conventional boost converter is the restriction of the maximum duty ratio. Though theoretically 99% duty is possible but in practical cases the duty is restricted after a certain level. Generally, a boost converter is used to generate maximum output voltage equal to four times of the input voltage [2]. If duty of the converter is increased to a higher value, then off time reduces which will be the cause of the reverse recovery problem and thus the Electromagnetics interreference (EMI) issue. If the off time is increased, it will increase the magnetics size and current ripple of the converter.[3] Another issue is that by increase in duty the voltage stress of the switch increases. Voltage level of a converter can be improved by using transformer which will increase the magnetics size of the converter. One of the most suitable way is to use some extra passive components to improve the gain of a non-isolated converter. To improve the gain of a boost converter several voltage lifting topologies are introduced in the past few years. In several voltage boost topologies, it is recommended to reduce the voltage stress of the switching devices. Generally, the voltage stress of the devices is equal to the output voltage. By increasing the voltage level of the switches on state resistance increases which reduces the efficiency. Some of the voltage lifting topology in input side increases the current ripple which increases the size of the bus capacitor. If two boost converters are connected in series then the voltage stress of one switch can be reduced whereas that of another switch becomes equal to the output voltage of the converter.

This paper proposes a novel DC-DC converter topology by using two switches. In this proposed topology the voltage stress for both the devices can be reduced. No series parallel combination of passive elements is used in the first stage of the converter which maintains the continuous input current as well as reduces the input current ripple of the converter which is highly recommended for a battery storage system. Though this converter is used for voltage boost application this converter is different form a boost converter. This proposed converter is capable to supply maximum output at lower duty as well as maximum duty. Both of the switch operates in complementary operation which reduces the complexity of the converter. Gain of the converter is more than two boost converters connected in series.

II. PROPOSED CONVERTER

This topology proposes a high gain DC-DC converter for voltage boosting application by reducing the input current ripple. This proposed topology follows the operation of a boost converter. To reduce the current ripple of the converter no passive component is used in parallel with the inductor L1 during its charging time. In this converter S1 is the main switch and S2 is the auxiliary switch. On time of the Switch S1 is DT. When the Switch S1 is off the auxiliary switch will conduct. Dead time is not required for this proposed converter. During the on time of S1 if S2 turns on then it will freewheel only the current of inductor L2. It will however, not be able to affect the load current or the capacitor C1 current because of the presence of diode D1 in reverse biased condition. This proposed converter follows some rules of the boost converter. During the on time of the switch S1 the inductor L1 is charged from the supply voltage Vs. In voltage lifting application some extra passive components are generally connected in parallel with the inductor of the boost converter during its charging time and connected in series during the discharging time which increases the input current ripple of the converter. In this proposed topology voltage lifting is not applied in the first stage of the converter which reduces the current ripple of the converter. One of the most advantageous points in this converter is that all of the switch voltage stress of this proposed converter is less than the output voltage. This converter will supply minimum input voltage at 50% of the duty cycle. This converter is capable to supply maximum voltage at the minimum duty as well as at the maximum duty. The second stage of the converter is controlled by the auxiliary switch S2. When the switch S1 turned off S2 turn on and the series combination of charged inductor and the supply voltage charge the parallel combination of the capacitor C1 and the inductor L2. When the auxiliary switch S2 is turned on the diode D1 is in reverse biased condition which makes the series combination of C1 and L1 which are already charged. So this series combination of capacitor and inductor increases the voltage level and transfer the energy to the load. The diode D2 is used to avoid the discharge of load during the charging of capacitor C1. As during transferring the power to the load, L2 and C2 are connected in series the load voltage cannot appear across the Switch S2 which reduces the voltage stress of the switch S2. With the reduction of the maximum voltage stress on state resistance of the switch decreases which improves the efficiency of the system. As the volage lifting is introduced in the second stage of the converter, it will not increase the input current ripple. The major difference of this converter from a boost converter is that during on time of the switch S1, energy is transferred to the load whereas in a boost converter energy is transferred to the load during the off period.

Conclusion

This proposed improved gain boost converter is designed by the help of equation and the passive elements are selected for the continuous conduction operation. The designed converter is simulated in MATLAB Simulink. All of the output waveform ensures about the continuous conduction of the passive elements. Output voltage of the converter obeys the equation by ignoring the small voltage drop of the semiconductor devices. This converter is suitable to deliver power from a 48V battery to a inverter DC bus to generate 110V AC. Inverter DC bus voltage require more than the equivalent DC voltage of the generated AC voltage due to the PWM control. This proposed converter can be applicable for low or medium power PV application where PV array voltage is not too much and the loads are operating at higher voltage.

References

[1] Debadyuti Banerjee, Anirban Giri, “Design And Simulation Of A High Gain Boost Converter With Continuous Input Output Current,” YMER,Volume 22, Issue 06, 2023 pp. 968-974. [2] Julio Cesar Rosas-Caro, Fernando Mancilla-David, Jonathan Carlos Mayo-Maldonado, Juan Miguel Gonzalez-Lopez, Hilda Lizeth Torres-Espinosa, Jesus Elias Valdez-Resendiz, “A Transformer-less High-Gain Boost Converter With Input Current Ripple Cancelation at a Selectable Duty Cycle,” IEEE TRANSACTIONS ON INDUSTRIAL ELECTRONICS, VOL. 60, NO. 10, OCTOBER 2013, pp. 4492-4499. [3] H. E. Mohamed and A. A. Fardoun, \"High gain DC-DC converter for PV applications,\" 2016 IEEE 59th International Midwest Symposium on Circuits and Systems (MWSCAS), Abu Dhabi, United Arab Emirates, 2016, pp. 1-4. [4] M. Veerachary, \"Two-switch High Gain Boost Converter,\" 2020 IEEE 17th India Council International Conference (INDICON), New Delhi, India, 2020, pp. 1-6. [5] S. Gore, A. Iqbal, P. Kiran Maroti, M. A. Al-Hitmi, R. Al-ammari and J. Lam, \"A Double Duty Converter: A New High Gain Modified Triswitching State Boost Converter for Nanogrid Application,\" IECON 2020 The 46th Annual Conference of the IEEE Industrial Electronics Society, Singapore, 2020, pp. 3132-3137. [6] L. Wang, D. Zhang, J. Duan and J. Li, \"A novel interleaving and magnetically integrated high gain boost converter used in new energy power system,\" 2018 13th IEEE Conference on Industrial Electronics and Applications (ICIEA), Wuhan, China, 2018, pp. 305-310. [7] A. Suganya and M. Sudhakaran, \"Performance analysis of high step-up DC-DC converter for photovoltaic (PV) system,\" 2015 International Conference on Circuits, Power and Computing Technologies [ICCPCT-2015], Nagercoil, India, 2015, pp. 1-8. [8] M. Zhu, T. Wang and F. L. Luo, \"Analysis of voltage-lift-type boost converters,\" 2012 7th IEEE Conference on Industrial Electronics and Applications (ICIEA), Singapore, 2012, pp. 214-219.

Copyright

Copyright © 2023 Debadyuti Banerjee, Anirban Giri. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.