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The control of the current distribution in a two leg interleaved inverter is analyzed in this paper. Feedback is used in order to control the current distribution on the inverter legs, avoiding the use of bulky and costly passive solutions. Low THD in the output voltage is ensured by a PI compensator and a repetitive controller. The design of the current compensators was accomplished by approximating...
The present work discuss the localization and coordinated operation of active power filters installed in a distribution power network. The localization problem is solved off-line for a given load variation scenario. The control of the current injected by the active power filter is solved on-line. In both cases the design solutions aim at reducing the total harmonic distortion below 5% and individual...
This paper introduces an analysis and design of a digital controlled double loop voltage-current for a buck converter. Taking into account the implementation requirements, the chosen platform was an Field-Programmable Gate Array (FPGA). This paper also shows in detail the analog-digital interface. The study is completed by a detailed analysis of the FPGA programming including states machines and logic...
Modular Multilevel Converters (MMCs) are a new circuit topology to realize multilevel converters. Major advantages of MMCs in comparison to other multilevel converters or standard Voltage Source Converters (VSCs) are lower costs and a modular design for high voltage applications, higher reliability and longer maintenance intervals. However, modular multilevel topologies generally require advanced...
Compared to the conventional analog-circuit control and linear power amplifier for permanent-magnet electrodynamic shaker (PMEDS), a DSP-based digital current control with switched-mode power amplifier is proposed in this paper. A full-bridge converter is connected directly to PMEDS without LC filter in order to directly regulate the shaker current and simplify the digital current control. To meet...
The dynamic performance of dc-dc power electronic converters is mainly determined by the output filtering capacitor and inductor, control loop(s) compensator(s), and the voltage conversion ratio. Normally, a larger capacitance and/or a smaller inductance are not recommended because of the extra cost and size of the capacitor and/or the increment of the inductor current ripple. The capacitor current...
Conventional hysteresis controllers have a major disadvantage of a variable switching frequency. This paper presents a variable hysteresis control method for implementing multilevel modulation of multilevel inverters with constant switching frequency, by using the current error zero crossing time to calculate the hysteresis bands in a switching period. This strategy makes algorithm independent of...
Solid state transformer (SST) is considered the key unit for power processing and conversion in the future distributed renewable energy network. The role of SST is to enable the active management of distributed energy resources, energy storage devices and different type of loads in a distribution grid. Inverter stage of SST supplies sinusoidal voltage to the users. In this paper an improved inductor...
This paper presents the positive feed-forward control (PFFC) scheme for the distributed buck conversion system with the multiple non-ideal voltage sources. Since the employed voltage sources are non-ideal, the output voltage level of the individual voltage source varies with the output current of the individual voltage source. Moreover, the employed voltage sources with the different electrical characteristics...
In the low inductance and small-sized brushless DC motor, the conventional PWM driving method makes relatively large copper loss because of an unintended directional transition current caused by ordinary complementary switching in the halfbridge circuits. We implemented the experimental feedforward current control system based on the method proposed by us in which the bridge circuits are driven non-complementarily...
Presently work exists within the IEEE to develop a test standard for Permanent Magnet AC (PMAC) machines that includes a specification on the quality of current supplied to the machine. The research presented in this paper offers a comparison on the quality of current provided to the machine for three control strategies; Space Vector, PI and Bang-Bang. The tests conducted were of an “on the fly” nature...
The servo system of a permanent magnet (PM) motor is always required to maintain fine torque and speed response. The current-control system is designed by using the electric parameters of the PM motor. However, motor parameters vary and the current sensors have offset values. When each U-phase and V-phase current sensor has an offset value, the PM motor servo system has the torque ripple and cannot...
A dual-inverter allows to increase easily the maximum available power of a given inverter. When connecting two equal inverters to a machine with open end windings, the available power will raise by factor √3. However, the dual inverter also introduces a new degree of freedom for the current, which is the zero component current. The dual inverter is known for developing zero component currents, which...
A new hybrid excitation permanent machine-doubly fed hybrid excitation permanent magnet synchronous machine without rotor winding is presented. The structure, mathematic model and operation principle of the machine are introduced. It is shown that excitation regulation can be realized by changing the current of stator control winding. The field control performance in the generator and motor operation...
Utilisation of wind energy to generate electricity has attracted considerable attention worldwide, and is rapidly-growing. The integration of large wind farms with high voltage direct current (HVDC) transmission network could be one of the preferred options for supplying bulk power over a long distance. Since HVDC rectifier stations with constant current control may introduce negative damping on the...
Non-sinusoidal back electromagnetic forces cause torque ripple in permanent magnet synchronous motors. These harmonics should be reduced by means of an appropriate current control to improve performance. Good results have been obtained with linear regulators such as repetitive controllers in synchronous reference frame (SRF) and resonant controllers in stationary frame. Repetitive controllers present...
This paper proposes a new voltage control technique for IPMSM drives to extend DC-link voltage utilization for flux weakening operation. The presented method does not require look-up-table and motor parameter for flux weakening operation. The difference between the switching period and summation of active switching times for PWM control of inverter is used to modify the d-axis current reference under...
A novel isolated zero-voltage-switching (ZVS) bidirectional DC-DC converter with coupled inductors is proposed in this paper. The parallel structure in the low-voltage side and the series structure in the high-voltage side are adopted to satisfy the high power and high step-up/down conversion requirements. Moreover, by employing the PWM plus phase-shift (PPS) control technology, the current stress...
Conventional control strategies, used in shunt active power filters (SAPF), employ real-time instantaneous harmonic detection schemes which are usually implemented with digital filters. This increases the number of current sensors on the filter structure which results in high cost. Furthermore, these detection schemes introduce time delays which can deteriorate the harmonic compensation performance...
With the progress of “More Electric Aircraft”, power capacity of aircraft electric power system is increased. It is not easy for the power-quality characteristics of the system to be in compliance with the harmonic standards by using traditional method to compensate the harmonics introduced by the nonlinear load. Active power filter (APF) gets increasing usage in 50Hz power system for its high performance...
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