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Flexible AC Transmission System (FACTS) is applied to manage a number of varied situations of the power line. The Unified Power Flow Controller (UPFC) as one of the FACTS is used in order to keep conditions of the power line. The UPFC consists of two components. One is connected in parallel to the power line, and the other is connected in series. By the parallel system, the reactive power and 3-phase...
IPMSM have attracted attention for its high efficiency. Extended electro motive force (EMF) based sensorless vector control system is one of the representative methods. In this paper, we propose a simplified sensorless vector control system without using an observer on the basis of the extended EMF. In order to verify the effectiveness of the proposed system, we perform stability analysis and comparison...
The power conditioning system (PCS) is widely used as a grid connected inverter for the photovoltaic system. The PCS applying a circuit construction of the modular multi-level converter (MMC) is investigated. the MMC is focused on as the transformer-less converter to realize light weight and downsizing. And it can be applied to a high voltage and high power convertor with less distorted output by...
The Modular Multilevel Converter (MMC) with cascaded full bridge cells enables the multi-level output and has the big merit that the system is not required the transformers when it is used as a distributed power supply in high voltage system. The control method of the MMC for single phase AC-AC conversion system investigated in this study. The full bridge type MMC, which is expanded from the half-bridge...
From the viewpoint of miniaturization and cost reduction, sensor-less vector control systems without using an encoder have been proposed in many papers. We proposed a simplified method which estimates the rotor position using the d-axis voltage without using observer and controls motor speed using the d-axis voltage too. In order to verify the effectiveness of the proposed method, we have performed...
The modular multilevel converter (MMC) with cascaded full bridge cells is available for an AC/AC transmission system without transformers in high voltage line. When it is interconnected with power line, it is possible to control the active power flow in order to supply the power to the power line. This research applied the MMC to grid connection system of distributed generator for single phase AC/AC...
The modular multilevel converter (MMC) with cascaded full bridge cells is available for a utility interactive inverter and AC/AC transmission system without transformers in high voltage line. When it is interconnected with power line, it is possible to control the active power flow in order to supply or charge the power in the line. This research applied a Hexagonal type MMC (H-MMC) to 3-phase AC-AC...
Flexible AC Transmission System (FACTS) component is available to manage a number of varied situations of the power line. The Unifier Power Flow Controller (UPFC) as one of the FACTS is used in order to keep conditions of the power line. The UPFC consists of two inverters. One is connected in parallel to the power line, the other is connected in series. In parallel side, the reactive power can be...
Distributed generation is violent fluctuations because it depends on output of the clean energy generation system. Thus a power leveling system (PLS) is applied to maintain a balance between power supply and such an irregular power generation. The PLS is required to operate charge or discharge of storage and bidirectional power flow. Thus the PLS consists of a bidirectional buck/boost DC/DC converter...
The power conditioning system (PCS) is widely used as a grid connected inverter to keep output constant. A novel power conditioning system (PCS) using a circuit of modular multi-level converter (MMC) construction is investigated. The feature of the system is that output voltage becomes multilevel for low distortion and circuit has an energy storage system such as a battery or an electric double layer...
Renewable energy system such as a photovoltaic, a wind turbine generation and fuel cell has attracted attention as alternative energy sources of fossil fuel. However, a distributed generating system with the photovoltaic or the wind turbine generation is difficult to obtain a constant power supply. Thus control of power leveling system is required to maintain the balance of power flow for irregular...
A non-singular terminal-sliding-mode (NTSM) observer which contains a high-order sliding mode is introduced into a direct torque control (DTC) system of permanent magnet synchronous motor (PMSM). The proposed system uses the non-singular terminal-sliding-mode observer to obtain the back electromotive force which is used to estimate the rotor position and speed of PMSM for sensorless DTC system. Compared...
Physical meaning of the conventional space vector of salient permanent magnet synchronous machine is studied. For this purpose, we define physical space vectors. The electromagnetic torque is derived by using the physical space vectors. A space vector diagram in transient state is derived and discussed.
Sensorless vector control of an interior permanent magnet synchronous motor (IPMSM) has been studied in many papers. The extended electromotive force (EMF) based method is one of the representative systems. We proposed a simplified method which estimates the rotor position using the controlled voltage without using observer. In this paper we have compared these methods through trajectories of poles...
As a distributed generation system increases, a stable power supply becomes difficult. Thus control of power leveling (PL) unit is required to maintain the balance of power flow for irregular power generation. The unit is required to respond to change of voltage and bidirectional power flow. So the bidirectional buck/boost DC/DC converter is applied for the control of PL unit in this research. The...
The Modular Multilevel Converter (MMC) with cascaded full bridge cells is available for AC/AC transmission system without transformers in high voltage line. This research applied a Hexagonal MMC (H-MMC) to 3-phase AC-AC back-to-back (BTB) system. The H-MMC has six arm modules with floating capacitors and is required to regulate the input-output power and capacitor voltages by controlling currents...
The Unified Power Flow Controller (UPFC) can flexibly manage power flow and maintain line voltage. The UPFC consists of two inverters in parallel side and series side. In parallel side, the reactive power can be compensated to improve the power factor. In series side, the voltage drop can be compensated to maintain proper line voltage. It is necessary for the operation in both sides to output the...
The Modular Multilevel Converter (MMC) with full bridge cells is available for a utility interactive inverter in high voltage line. When it is interconnected with power line, it is possible to control the active power flow in order to supply or charge the power in the line. This research applied a Hexagonal MMC to 3-phase AC-AC conversion system. The system is controlled by internal model principle...
As a distributed generation system increases, a stable power supply becomes difficult. Thus control of power leveling (PL) unit is required to maintain the balance of power flow for irregular power generation. The unit is required to respond to change of voltage and bidirectional power flow. So the bidirectional buck/boost DC/DC converter is applied for the control of PL unit in this research. The...
Physical meaning of the instantaneous space vector of salient permanent magnet synchronous machine is studied. For this purpose, we define real physical space vectors. The electromagnetic torque is derived by current and flux densities. A space vector diagram in transient state is derived and discussed.
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