A Control Map for a Bidirectional PWM Plus Phase-Shift-Modulated Push-Pull DC-DC Converter
Abstract
In this paper, a bidirectional push-pull converter is investigated with new add-on feature of three-level PWM plus phase-shift (PPS) control scheme, and a control map is proposed to assist converter operation and design in the optimized region. The PPS control strategy is adopted to reduce peak current of the transistors, to increase the input-voltage-variation range and to expand the soft-switching region. A comprehensive analysis of operation principle, transmission capability and soft-switching operation in 12 different operation modes is presented. Based on the complete analysis, a control map is proposed to assist converter operation that can effectively avoid high-circulating-current regions, low-power-transmission-capability regions, and hard-switched regions. In the control map, a circuit parameter k is signified and its range is found, beyond which the PPS converter no longer operates normally. The proposed control map and the circuit parameter k are general to all PPS converters, providing a meaningful analyzing method to design and operate all PPS converters. A 30~48V/380V prototype rated at 100~1000W was built under the guideline. The analysis is verified by both simulation and experimental results.
PROPOSED SYSTEM:
So far PPS control has only been applied to a specific group of converters. In this paper, the PPS control strategy is extended to a bidirectional push-pull converter whose structure originated from [18]. With the PPS control, the transistor channel rather than the parasitic diode conducts the current in steady-state periods, avoiding the diode reverse recovery phenomenon. Meantime, the input-voltage-variation range and the soft-switching operation region of the primary transistors are expanded. A comprehensive analysis of 12 different operation modes is presented. Based on this understanding, a control map and a circuit parameter k are proposed to assist converter design and operation that can avoid high-circulating-current regions, low-power-transmission -capability regions, and hard-switched regions. The proposed control map can provide a guideline about how to choose the duty cycle and the corresponding phase-shift value to achieve PPS control. The limit of the circuit parameter k is found, beyond which the PPS converter no longer operates normally. The above analyzing method is suitable for all PPS converters. A 30~48V/380V prototype rated at 100~1000W was built to verify the analysis.
EXISTING SYSTEM:
A dual half bridge with phase-shift control was proposed in. It has small input current ripple and large voltage gain. But in many IBDC applications, both dc buses have voltage variations imposed by the system. When the voltage amplitudes of the primary side and secondary side are not matched, the current stress and circulating current become much higher, deteriorating the efficiency badly. For a specific group of IBDCs, the PWM plus phase-shift (PPS) control strategy can be adopted. In those two-level PPS converters, the duty cycle is controlled to match the voltage amplitudes of the two-level square waves on both sides, while phase-shift angle is regulated to control the power flow. Low current stress, large ZVS range and wide input-voltage-variation range can be achieved. With this control, the voltage on the transformer’s primary side becomes a three-level square wave with an extra zero level, defined as a three-level PPS converter. Similarly, another three-level PPS converter was reported. However, provided complete analysis about different operation modes to find the optimized region. In addition, the relationship between duty cycle and phase-shift ratio in different operation modes was not revealed, bringing difficulties to operate the PPS converters. the traditional current-fed push-pull with active clamp was proposed. This converter applies PWM control and it has small input current ripple with the help of the input inductor. But the secondary-side diodes are hard switched, causing high reverse recovery current.], a unidirectional resonant push-pull converter was proposed, whose structure originated from The ZCS operation of the secondary diodes can be obtained. However, due to the resonance, the voltage stress and current stress of the components are much higher. And the resonant tank should be carefully designed to ensure the normal operation a bidirectional resonant push-pull converter is modified based on , to regulate bidirectional power flow.
CONCLUSIONS
In this paper, a bidirectional three-level PPS converter is investigated with new add-on feature of PPS control scheme. Extensive analysis is presented to reveal the comprehensive characteristics for this converter. According to different profiles of leakage current waveform, 12 operation modes are traversed. A control map based on the complete analysis is proposed to assist converter design and operation that can effectively avoid high-circulating-current regions, low-power-transmission-capability regions and hard-switched regions. A 30~48V/380V prototype rated at 100~1000W was built to verify the analysis.
REFERENCES
[1] Hamid R. Karshenas, Hamid Daneshpajooh, Alireza Safaee, Praveen Jain and Alireza Bakhshai (2011). Bidirectional DC – DC Converters for Energy Storage Systems, Energy Storage in the Emerging Era of Smart Grids, Prof. Rosario Carbone (Ed.), ISBN: 978-953-307-269-2, InTech, Available from: http://www.intechopen.com/books/energy-storage-in-the-emerging-era-o f-smart-grids
[2] Xiao Li; Bhat, A.K.S., “Analysis and Design of High-Frequency Isolated Dual-Bridge Series Resonant DC/DC Converter,” in Power Electronics, IEEE Transactions on , vol.25, no.4, pp.850-862, April 2010
[3] Kheraluwala, M.N.; Gascoigne, R.W.; Divan, D.M.; Baumann, E.D., “Performance characterization of a high-power dual active bridge DC-to-DC converter,” in Industry Applications, IEEE Transactions on , vol.28, no.6, pp.1294-1301, Nov/Dec 1992
[4] De Doncker, R.W.A.A.; Divan, D.M.; Kheraluwala, M.H., “A three-phase soft-switched high-power-density DC/DC converter for high-power applications,” in Industry Applications, IEEE Transactions on , vol.27, no.1, pp.63-73, Jan/Feb 1991
[5] Jain, A.K.; Ayyanar, R., “Pwm control of dual active bridge: Comprehensive analysis and experimental verification,” in Power Electronics, IEEE Transactions on , vol.26, no.4, pp.1215-1227, April 2011
[6] Biao Zhao; Qingguang Yu; Weixin Sun, “Extended-Phase-Shift Control of Isolated Bidirectional DC–DC Converter for Power Distribution in Microgrid,” in Power Electronics, IEEE Transactions on , vol.27, no.11, pp.4667-4680, Nov. 2012
[7] Hua Bai; Mi, C., “Eliminate Reactive Power and Increase System Efficiency of Isolated Bidirectional Dual-Active-Bridge DC–DC Converters Using Novel Dual-Phase-Shift Control,” in Power Electronics, IEEE Transactions on , vol.23, no.6, pp.2905-2914, Nov. 2008
[8] Biao Zhao; Qiang Song; Wenhua Liu, “Power Characterization of Isolated Bidirectional Dual-Active-Bridge DC–DC Converter With Dual-Phase-Shift Control,” in Power Electronics, IEEE Transactions on , vol.27, no.9, pp.4172-4176, Sept. 2012
[9] Biao Zhao; Qiang Song; Wenhua Liu; Yan Sun, “Overview of Dual-Active-Bridge Isolated Bidirectional DC–DC Converter for High-Frequency-Link Power-Conversion System,” in Power Electronics, IEEE Transactions on , vol.29, no.8, pp.4091-4106, Aug. 2014
[10] Karshenas, H.R.; Daneshpajooh, H.; Safaee, A.; Bakhshai, A.; Jain, P., “Basic families of medium-power soft-switched isolated bidirectional dc-dc converters,” in Power Electronics, Drive Systems and Technologies Conference (PEDSTC), 2011 2nd , vol., no.,