Reference signal generator for active power filters using MGP-FIR filter designed by evolutionary programming

This paper describes a high-performance reference signal generator for active power filters extracting the fundamental signal component from distorted current signals. In order to achieve high-quality output as well as computationally effective algorithm, the generator employs an adaptive and predictive MGP-FIR (Multiplicative General Parameter) bandpass filter designed by evolutionary programming. Detailed procedures of MGP-FIR filtering and evolutionary optimization are first discussed; theoretical conclusions are verified by illustrative simulation results.reviewe

Comparison of Si and SiC based Power Converter Module of 150 kVA for Power System Applications

The paper deals with the comparison of power semiconductors based on Si and SiC in application of power converters for power systems. These are single-phase voltage-source bridge inverters with nominal power of 150 kVA. Power converters are designed to operate under both active power and reactive power. Mechanical design of the converters is ready for interchange the power semiconductor modules and assess the operation with both, Si and SiC technology

Fast Real-Time Data Exchange among Distributed Control System of STATCOM Installation

SGS-2021-021Power installations based on power converters in power transmission and power distribution require real-time control which is usually implementing using multiple control units. Therefore, very fast data exchange within constant sampling periods across whole control system is needed. This paper deals with the development and implementation of a specific communication protocol for an embedded modular control system. The communication protocol employs LVDS bus and it is designed for fast data exchange between master and slave control units. The protocol is used in control system REMCS of a STATCOM of 1.35MVA installed in distribution power grid of 22 kV

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Pulse width modulation of three phase inverters based on linear programming

Traditional three-phase voltage-source inverters supplied by constant dc-link voltage usually utilize the space vector PWM to achieve maximum output voltage. This paper deals with optimization of inverter leg voltages using linear programming method. System definition is based on the relationship between the known voltage vector, which is demanded by an upper control loop and the unknown leg voltages which enter the carrier-based PWM block as modulation signals. A slack variable is introduced to the system as minimization objective, defining border for all leg voltages. Optimization procedure minimizes leg voltage maxima, and thus, the maximum utilization of the dc-link voltage is ensured. The theoretical assumptions have been verified by simulations as well as by experiments on laboratory prototype

Minimum infinity norm-based PWM for three-phase four-leg converters

Control of four-leg voltage-source converters operating on three-phase systems traditionally faces the problem of transformation from a four-degrees of freedom (DOF) modulation space to a three-DOF output-voltage space. Contemporary, it is highly desirable to minimize the leg voltage, and consequently the dc-link voltage, especially because of positive impact on cost-effective dimensioning of power electronics modules. In order to meet these requirements, a novel universal PWM method is proposed. It is based on calculation of the minimum infinity norm and tailored for control of four-leg converters operating in applications with both, balanced and unbalanced output voltage. In order to verify its universality, it has been employed in two different applications, namely a three-phase four-leg inverter supplying an unbalanced load and a four-leg compensator of earth faults in distribution power grids. Capability of the proposed modulation algorithm to control the four-leg converters in various applications while minimizing the dc-link voltage has been verified by experiments on two designed laboratory prototypes

Multiphase Converter Voltage Optimization with Minimum Effort Principle

Multiphase converters are systems with multiple degrees of freedom (DOF) and provide space for control optimization. Widely-spread space vector PWM methods offer competitive results. However, they are rather complicated due to high number of switching states and are designed for a specific n -phase system or operation mode. For special cases, e.g. when total harmonic distortion (THD) should be reduced or fault-tolerant mode is required, they lead to complicated and specialized solutions. In this paper, a minimum effort principle for leg-voltage optimization is proposed. This efficient approach is based on the minimum infinity norm solution and it effectively exploits the DOF. It is shown that the approach is universal and applicable to n -phase systems and to both standard and fault-tolerant modes. Moreover, it enables to implement constraints on DOF and adjust trade-off between maximum output voltage and THD. To meet the requirements of real-time applications, an effective algorithm of low processing power is proposed

Four-Leg Transformer with Defined Zero Sequence Impedance for Ground Fault Compensation

Single-phase ground faults are the most common faults in medium-voltage distribution grids. High-impedance grid grounding using a special four-leg transformer is discussed in the paper. The transformer’s zero-sequence impedance differs from positive-sequence impedance and it is designed to compensate the earth faults currents in Medium Voltage (MV) distribution grids when single-phase ground fault occurs. The designed transformer can replace the traditional arc suppression coils (ASC) in the case where no distribution transformer neutral is available or distributed compensation is required. Alternatively, the transformer can operate in parallel with the ASC

Fast Real-Time Data Exchange among Distributed Control System of STATCOM Installation

Power installations based on power converters in power transmission and power distribution require real-time control which is usually implementing using multiple control units. Therefore, very fast data exchange within constant sampling periods across whole control system is needed. This paper deals with the development and implementation of a specific communication protocol for an embedded modular control system. The communication protocol employs LVDS bus and it is designed for fast data exchange between master and slave control units. The protocol is used in control system REMCS of a STATCOM of 1.35MVA installed in distribution power grid of 22 kV

Modular STATCOM for compensation of reactive power and voltage asymmetry in medium-voltage distribution power grids

A cost-effective STATCOM is proposed and discussed in this paper. Its modular topology enables to scale the power to target systems. Besides reactive power, the proposed STATCOM enables to generate a zero-sequence component and compensate the voltage asymmetry, e.g., in widely spread medium-voltage distribution power grids with resonant grounding