IJRIT International Journal of Research in Information Technology, Volume 3, Issue 6, June 2015, Pg.222-227

International Journal of Research in Information Technology (IJRIT) www.ijrit.com

ISSN 2001-5569

Hybrid Boost Converter for Simultaneous AC and DC Outputs Akash Mohan J, Nagesh B K M.tech 4th sem student, Department of EEE, REVA Institute of Technology and Management Bangalore, Karnataka, India [email protected] Associate Professor, Department of EEE, REVA Institute of Technology and Management Bangalore, Karnataka, India [email protected]

Abstract This Project introduces a new hybrid converter topology that can supply AC and DC loads simultaneously from a single DC input. By changing the controlled switch of traditional boost converter with voltage source inverter (VSI) bridge network the new Hybrid Converter can be performed. The altered hybrid converter has lesser number of switches compared to conventional one, which also provides DC and AC outputs with an increased stability, resulting in protection of shoot through effect in the inverter stage. The altered converter is called hybrid-boost-converter (HBC) as it is obtained from conventional boost converter. For controlling switches a suitable PWM control strategy, based on unipolar Sine-PWM is explained. Simulink model is used to verify the operation of the converter. The altered Converter can supply AC load of 30V RMS and DC load of 175V from a 48V DC supply. The simulations were performed using MATLAB/SIMULINK.

Keywords:-Voltage source inverter(VSI), Hybrid Boost Converter(HBC).shoot-through protection, Duty ratio, Modulation index.

1. Introduction The proposed system there is DC and AC loads supplied by DC sources (battery, PV cells etc.) using efficient power electronic converters. Fig.1 shows the schematic of the system in which single DC source supplies both AC and DC loads. Figure.1 (a) shows the conventional system in which DC and AC load supplied by separate DC-DC converter and DC-AC inverter from a single DC source respectively. Whereas in Figure.1 (b) referred as hybrid converter in which a single converter stage perform both operations. This hybrid converter has the property of higher power processing capability and improved reliability resulting from the inherent shoot through protection. This paper investigates the use of single boost stage architecture to supply hybrid loads.The conventional VSI in Hybrid converter would involve the use of dead time circuitry to manage the shoot-through. Also misfiring of switches may take place due to various noise resulting in damage of switches. So VSI in such application need to be highly reliable with appropriate measures against shoot-through and EMI induced misfiring of switches. Akash Mohan J,

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IJRIT International Journal of Research in Information Technology, Volume 3, Issue 6, June 2015, Pg.222-227

(a)

(b)

Figure 1. Architectures supplying DC and AC load from a single DC source. (a) Dedicated power converter based architecture and (b) Hybrid converter based architecture

2. Hybrid Boost Converter 2.1 Proposed circuit modification Conventional boost circuit is having two switches, one is a controllable switch (controls the duty cycle) and other can be implemented using a diode. Hybrid converter can be realized by replacing controllable switch in the boost circuit with a voltage source inverter, either single phase or three phase Voltage Source Inverter (VSI). The resulting converter called as Hybrid Boost Converter (HBC).

2.2 Derivation of HBC topology Control-switch Q of a boost converter (shown in Figure. 2(a)) is replaced with a single phase inverter bridge network, switches (Q1-Q4) to obtain Hybrid Boost Converter (shown in Figure. 2(b)). AC and DC outputs are controlled using same set of switches (Q1-Q4). So challenges involved in the operation of HBC are, defining duty cycle (D) for boost operation and modulation index (M) for inverter operation

Duty ratio is determined by: (1)

And Modulation Index is determined by (2)

Figure 2. (a) Conventional boost converter, (b) Proposed Hybrid Boost converter obtained by replacing Qa with a single phase inverter bridge network

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3. Operation of HBC The boost operation is obtained by switching on both switches of a particular leg (Q1-Q4 or Q3-Q2). This is equivalent to shoot through operation in VSI operation. However in the operation of hybrid converter operation this is equivalent to switching on controllable switch Qa of the conventional boost converter. The ac output is controlled using a modified version of the unipolar sine width modulation [4]. The HBC during inverter operation has the same circuit states as the conventional VSI. The switching scheme must ensure that the power transfer with source occurs only when sn is positive. The HYBRID BOOST CONVERTER has three distinct switching states as described below:

3.1 Interval 1: Shoot-Through interval Figure. 3.1 showing the equivalent circuit during shoot-through interval. In this interval we adjust the duty cycle for the boost operation by turning on both switches of any particular leg at the same time. Diode D is reverse biased during this interval. Inverter current circulates within the bridge switches.

Figure 3.1. Shoot through interval (Boost operation)

3.2 Interval 2: Power interval Figure. 3.2 showing the equivalent circuit during power interval. Here inverter current enters or leaves through switch node terminal Q. Switches Q1-Q2 or Q3-Q4 turned on. Diode is forward biased. Power delivered to both ac and dc loads.

Figure 3.2. Power interval

3.3 Interval 3: Zero interval Figure. 3.3 showing the equivalent circuit during zero interval. Here diode is in forward biased condition and power delivered to dc load. Inverter current circulates within the bridge switches.

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Figure 3.3. Zero interval

4. Simulation and Results As we have understood the circuit operation in the section 3, now it is necessary to simulate the circuits in MATLAB/SIMULINK. The parameters for the simulation is shown in the below table. The circuit of Hybrid Boost Converter (HBC) is simulated as shown in the Figure 4, the results of this converter is shown in the Figure 5 and gate pulses as shown in Figure 6. TABLE I PARAMETERS FOR SIMULATION Symbols Vdci Vdc0 Vac0 Rac fr Q Lac Cac C0 Lmin Rdc fs

Names Input DC voltage Output DC voltage Output AC voltage ac load Resistance Resonant frequency Quality factor Inductor (Lac1 + Lac2) Capacitor (Cac) Minimum capacitance Minimum inductance dc load Resistance Switching frequency

Values 48V 180V 30V 10ohms 1kHz 2.48 3.95mH 6.41µF 1000µF 72µH 20ohms 20kHz

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Figure 4. Simulink model of Hybrid Boost converter.

Figure 5. Waveforms of DC output voltage, AC output voltage

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Figure 6. Gate pulses to the switches

5. Conclusions The circuit of Hybrid Boost Converter is simulated using MATLAB/SIMULINK. The simulation results shows that it can perform as boost converter as well as single phase inverter without any problem of shoot– through condition and absolute control over AC and DC output and the converter can also be suitable to generate AC outputs at frequencies other than line frequencies by a proper choice of the reference carrier waveform.

References [1] Ray and S. Mishra, “Boost-Derived Hybrid Converter with Simultaneous DC and AC Outputs,” in IEEE Transactions on Industry Applications, vol. PP, July. 2013. [2] Jince Jose, Emmanuel Babu, Aleyas.M.V “Boost & Buck-Boost Derived Hybrid Converter for Simultaneous DC & AC Applications” in IJERD Volume 10, Issue 2 (February 2014), PP.94-99 [3] F. Z. Peng, M. Shen, and Z. Qian, “Maximum boost control of the Z-source inverter,” IEEE Trans. Power Electron., vol. 20, no. 4, pp. 833– 838, Jul. 2005 [4] R. Adda, S. Mishra, and A. Joshi, “A PWM control strategy for switched boost inverter,” in Proc. IEEE ECCE, Phoenix, AZ, USA, Sep. 2011, pp. 991–996. [5] M. Shen, J. Wang, A. Joseph, F. Z. Peng, L. M. Tolbert, and D. J. Adams, “Constant boost control of the Z-source inverter to minimize current ripple and voltage stress,” IEEE Trans. Ind. Appl., vol. 42, no. 3, pp. 770–778, May/Jun. 2006. [6] S. Mishra, R. Adda, and A. Joshi, “Switched-boost inverter based on inverse Watkins-Johnson topology,” in Proc. IEEE ECCE, Phoenix, AZ, USA, Sep. 2011, pp. 4208–4211. [7] S. Upadhyay, R. Adda, S. Mishra, and A. Joshi, “Derivation and characterization of switchedboost inverter,” in Proc. 14th Eur. Conf. Power Electron. Appl.—EPE, Birmingham, U.K., Aug. 2011, pp. 1–10. [8] D. Maksimovic and S. Cuk, “Switching converters with wide dc conversion range,” IEEE Trans. Power Electron., vol. 6, no. 1, pp. 151–157, Jan. 1991.

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