• Journal of Power Electronics
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• v.13 no.2
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• pp.296-303
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• 2013

This paper proposes a high efficiency three-phase cascaded phase shifted H-bridge multi-level inverter without DC/DC converters for grid-tied multi string photovoltaic (PV) applications. The cascaded H-bridge topology is suitable for PV applications since each PV module can act as a separate DC source for each cascaded H-bridge module. The proposed phase shifted H-bridge multi-level topology offers advantages such as operation at a lower switching frequency and a lower current ripple when compared to conventional two level topologies. It is also shown that low ripple sinusoidal current waveforms are generated with a unity power factor. The control algorithm permits the independent control of each DC link voltage with a maximum power point for each string of PV modules. The use of the controller area network (CAN) communication protocol for H-bridge multi-level inverters, along with localized PWM generation and PV voltage regulation are implemented. It is also shown that the expansion and modularization capabilities of the H-bridge modules are improved since the individual inverter modules operate more independently. The proposed topology is implemented for a three phase 240kW multi-level PV power conditioning system (PCS) which has 40kW H-bridge modules. The experimental results show that the proposed topology has good performance.

• Journal of Power Electronics
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• v.16 no.5
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• pp.1763-1772
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• 2016

To reduce system complexity and implementation costs, fully-controlled H-bridge (FHB) modules and diode H-bridge PFC (DHB) modules are cascaded to form a hybrid cascaded H-bridge rectifier (HCHR). In this paper, the advantages of such a HCHR over other cascaded rectifiers are analyzed depending on the numbers of FHB modules and DHB modules. Therefore, to assign proper numbers to these two kinds of modules for the HCHR, a configuration determination method is investigated under balanced and imbalanced loads. Three principles are also presented to guide the configuration determination for the HCHR. In addition, the constraints for selecting the step-up ratio and filter inductance are derived based on a phasor diagram analysis. The proposed configuration determination method is validated by simulations under three different conditions in the PSIM environment. Finally, experiments are carried out on a scaled-down prototype where the configuration can be easily adjusted. The feasibility of the proposed theory is then verified by experimental results.

• The Transactions of the Korean Institute of Electrical Engineers B
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• v.52 no.12
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• pp.641-648
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• 2003

This paper proposes a novel UPFE based on H-bridge modules, isolated through single-phase multi-winding transformers. The dynamic performance of proposed system was analyzed by simulation with EMTDC, assuming that the UPFC is connected with the 138-kV transmission line of one-machine-infinite-bus power system. The proposed system can be directly connected to the transmission line without series injection transformers. It has flexibility in expanding the operation voltage by increasing the number of H-bridge modules.

• The Transactions of the Korean Institute of Electrical Engineers A
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• v.54 no.1
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• pp.1-7
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• 2005

This paper proposes a novel UPQC(unified power quality conditioner) based on H-bridge modules, isolated through single-phase multi-winding transformers. The dynamic performance of proposed system was analyzed by simulation with PSCAD/EMTDC, assuming that the UPQC is connected with the 22.9kV distribution line. The proposed system can be directly connected to the transmission line without series injection transformers. It has flexibility in expanding the operation voltage by increasing the number of H-bridge modules and can compensate reactive power, harmonics, voltage sag and swell, voltage unbalance. The proposing UPQC has the ultimate capability of improving power quality at the point of installation on power distribution systems.

• The Transactions of the Korean Institute of Electrical Engineers B
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• v.54 no.9
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• pp.422-430
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• 2005

This paper describes experimental analysis of UPFC, which is composed of cascaded H-bridge modules and single-phase multi-winding transformers for isolation. The operational characteristic was analyzed through experimental works with a scaled model, and simulation results with PSCAD/EMTDC. The UPFC proposed in this paper can be directly connected to the transmission line without series injection transformers. It has flexibility to expand the operation voltage by increasing the number of H-bridge modules. The analysis results can be utilized to design the actual WFC system applicable for the transmission system.

• Proceedings of the KIPE Conference
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• 2005.07a
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• pp.389-391
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• 2005

This paper describes experimental analysis of UPFC, which is composed of cascaded H-bridge modules and single-phase multi-winding transformers for isolation. The operational characteristic was analyzed through experimental works with a scaled model, and simulation results with PSCAD/EMTDC. The UPFC proposed In this paper can be directly connected to the transmission line without series injection transformers. It has flexibility to expand the operation voltage by increasing the number of H-bridge modules. The analysis results can be utilized to design the actual UPFC system applicable for the transmission system.

• The Transactions of the Korean Institute of Electrical Engineers P
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• v.53 no.3
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• pp.116-121
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• 2004

This paper proposes a novel UPFC based on 3-level Half-bridge modules, isolated through single-phase multi-winding transformers. The dynamic performance of proposed system was analyzed by simulation with EMTDC, assuming that the UPFC is connected with the 138-kV transmission line of one-machine-infinite-bus power system. The proposed system can be directly connected to the transmission line without series injection transformers. It has flexibility in expanding the operation voltage by increasing the number of 3-level Half-bridge modules.

• Journal of international Conference on Electrical Machines and Systems
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• v.2 no.2
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• pp.190-196
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• 2013

It presents a unification of buck-boost and flyback converter for driving a cascaded H-bridge multilevel inverter with a single independent DC voltage source. Cascaded H-bridge multilevel inverter is useful to make many output voltage levels for sinusoidal waveform by combining two or more H-bridge modules. However, each H-bridge module needs an independent DC voltage source to generate multi levels in an output voltage. This topological characteristic brings a demerit of increasing the number of independent DC voltage sources when it needs to increase the number of output voltage levels. To solve this problem, we propose a converter combining a buck-boost converter with a flyback converter. The proposed converter provides independent DC voltage sources at back-end two H-bridge modules. After analyzing theoretical operation of the circuit topology, the validity of the proposed approach is verified by computer-aided simulations using PSIM and experiments.

• Journal of international Conference on Electrical Machines and Systems
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• v.1 no.4
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• pp.448-456
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• 2012

This paper presents a multilevel inverter configuration which is designed by insertion of a bidirectional switch between capacitive voltage sources and a conventional H-bridge module. The modified inverter can produce a better sinusoidal waveform by increasing the number of output voltage levels. By serial connection of two modified H-bridge modules, it is possible to produce 9 output voltage levels including zero. There are 24 basic switching patterns with the 9 output voltage levels. Among the patterns, we select the 2 most efficient switching patterns to get a lower switching loss and minimum dv/dt stress. We then analyze characteristics of Total Harmonic Distortion (THD) of the output voltage with variation of input voltage by computer-aided simulations and experiments.

• Proceedings of the KIPE Conference
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• 2001.10a
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• pp.539-545
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• 2001

This paper proposes a static synchronous series compensator based on multi-bridge inverter. The proposed system consists of 6 H-bridge modules per phase, which generate 13 pulses for each half period of power frequency. The dynamic characteristic was analyzed by simulations with EMTP code, assuming that it is inserted in the 154-kV transmission line of one-machine-infinite-bus power system. The feasibility of hardware implementation was verified through experimental works using a scaled model. The proposed system does not require a coupling transformer for voltage injection, and has flexibility in expanding the operation voltage by increasing the number of H-bridge modules.