This invention provides a Delta Hybrid Modular Multilevel Converter (DHMMC). The DHMMC comprises of at least three primary chain-links and an auxiliary chain-link. Each of the at least three primary chain-links and the auxiliary chain-link are inter-connected through at least one inductor to form a delta configuration, and each of the at least three primary chain-links and the auxiliary chain-link comprises a predefined number of chopper cell modules. The DHMMC further comprises at least three bridge modules configured to receive output from the predefined number of chopper cell modules in each of the at least three primary chain-links and at least three single-phase transformers configured to receive output from the at least three bridge modules. Preselected windings of the at least three single-phase transformers are connected in a predefined manner to feed ac grid in the DHMMC.
Type of IP
Faculty
Category of Patent
Department
- Occupies less footprint and offers less cost and hence is likely to consume less funds from the government (save tax payers money) in the installment process.
- Improves power quality of the grid and hence prevents emergency loads (such as medical equipment, military equipment).
This patent proposes a new Hybrid Modular Multilevel Converter (HMMC) converter which is named as Delta-HMMC-STATCOM (DHMMC) as shown in Fig. 1. The proposed DHMMC has lower number of energy storing devices, smaller capacitance size, and low switching losses compared to MMC. The proposed DHMCC configuration has a provision for circulating current which can be controlled to balance the capacitor voltages of the chain-links when the converter is feeding an unbalanced network. Also, during unbalanced conditions, the capacitor voltages of the DHMMC can be regulated by injecting common mode voltage to the chain-links unlike the conventional Delta Cascade H-bridge configuration. Hence, the DHMMC has two degrees of freedom for regulating the capacitor voltages during unbalance. The proposed converter can operate in the full range of modulation index, since there is no fixed DC link. The auxiliary chain-link does not have any H-bridge associated with it nor does it feeds any power to the grid but still the auxiliary chain-link plays a vital role for forming the closed loop.
This patent proposes a new Hybrid Modular Multilevel Converter (HMMC) converter which is named as Delta-HMMC-STATCOM (DHMMC) as shown in Fig. 1. The proposed DHMMC has lower number of energy storing devices, smaller capacitance size, and low switching losses compared to MMC. The proposed DHMCC configuration has a provision for circulating current which can be controlled to balance the capacitor voltages of the chain-links when the converter is feeding an unbalanced network. Also, during unbalanced conditions, the capacitor voltages of the DHMMC can be regulated by injecting common mode voltage to the chain-links unlike the conventional Delta Cascade H-bridge configuration. Hence, the DHMMC has two degrees of freedom for regulating the capacitor voltages during unbalance. The proposed converter can operate in the full range of modulation index, since there is no fixed DC link. The auxiliary chain-link does not have any H-bridge associated with it nor does it feeds any power to the grid but still the auxiliary chain-link plays a vital role for forming the closed loop.
- Validated with simulations and theoretical analysis
- A prototype has been developed
- Experimental Results need to be analyzed to validate the operating principles
HITACHI Energy Private Limited, ABB, GENERAL ELECTRIC, SIEMENS, LARSEN & TOUBRO.
- Very much suitable for FACTS and high/medium voltage power system applications.
- Useful for high voltage and medium voltage applications, simple, easy to adopt, modular construction, energy storage required to generate an output of one MVA is less, lesser number of capacitors, lower capacitor size, lower switching losses, Zero Voltage Switching (ZVS soft switching) capability, can be applied to compensate unbalance in grid/load,