Stanislaw Pirog

Results of Investigation of Multicell Converters With Balancing Circuit—Part II

This paper presents the results of an investigation of the multilevel multicell converters with a passive RLC balancing circuit applied for the maintenance of the voltage sharing on the capacitive sources of the converters. The topologies of DC/DC, AC/AC, DC/AC, and AC/DC multicell converters were analyzed. For the purpose of multilevel modulation, a multicell converter employs several capacitors that are connected to every cell-the flying capacitors, charged to a given level of voltage. An inadequate relation between the voltages across the flying capacitors (the unbalance state) results in the increase of the voltages above their rated values across the switches. An RLC series circuit (a balancing circuit) with the properly selected resonance frequency is connected in parallel to the load in order to eliminate the unbalance. The balancing process with the use of passive RLC depends on the configuration and parameters of the balancing circuit, the parameters of the converter, as well as on the operating conditions. This paper presents the mathematical description of both the converter and the balancing process, the balancing circuit approach in the different topologies of the multicell converters, a selection of the balancing circuit parameters, and the analysis of the improper control conditions.

A Novel Speed Measurement Method for a High-Speed BLDC Motor Based on the Signals From the Rotor Position Sensor

The paper presents a digital algorithm of a speed control block for a dc brushless motor and a method for measuring the motors rotational speed based on the signals from the rotors position sensor. The proposed method allows an increase in the measurement frequency (six measurements per rotation for a two-pole motor or 12 measurements for a four-pole motor) and the measurement results are not affected by the misalignment mounting of the sensor. The paper describes a conceptual structure of a series PI controller.

High-Power Thyristor-Based DC–DC Switched-Capacitor Voltage Multipliers: Basic Concept and Novel Derived Topology With Reduced Number of Switches

This paper presents concepts and results of an investigation of power electronic thyristor-based switched-capacitor voltage multipliers (SCVMs). A concept of the SCVM power converters assumes the utilization of resonant circuits for the zero-current switching operation. The topology makes it possible to apply thyristors as active switches that create the possibility of composing the resonant switch-mode converters for high-voltage gain, high power, and low cost, and opens a huge area of applications. This paper presents an in-depth analysis of the SCVM configured as the resonant high-power thyristor-based converter. The operation with regard to the specific switching conditions of thyristors, as well as efficiency of the converter is analyzed providing the unique relationship important for the converter design, optimization, and efficiency improvement. An experimental validation confirms the feasibility and the operation concept of the SCVM and demonstrates the efficiency range. The SCVM converter can be optimized to the topology with a decreased number of switches. This paper also presents a novel topology of the resonant converter with a reduced number of switches, resonant switched capacitor voltage multiplier (RSCVM), dedicated for thyristor implementation. The RSCVM requires the specific component selection and control. The analysis of the configuration, operation, efficiency, and component selection of the RSCVM converter, as well as simulation and experimental results are presented.

Energy storage systems the flywheel energy storage

Storage of energy is one of the main problem of contemporary technology. Currently used manners of the energy store are listed below: (1) the magnetic accumulator - the energy is kept in the magnetic field of superconductive inductor, (2) the accumulator with super capacitors. The low voltage (1,6-2,5 V) is the fault of this one,(3) the accumulator with lead-acid or alkaline accumulator. The fault of this solution is very low charging and discharging efficiency, (4) the electromechanical accumulator. Flywheels store energy mechanically in the form of kinetic energy. In this article the flywheel energy storage will be described precisely and compared with other energy storage technologies.

The control and structure of the power electronic system supplying the Flywheel Energy Storage (FES)

The paper presents an experimental investigation of a flywheel energy storage system. The device is based on a flywheel concept and stores mechanical energy. This device contains a brushless DC motor supplied by an electronic commutator. A steel barrel performs the function of the flywheel. From the power network side this device is perceived as a resistive load. This is achieved owing to the use of the rectifier with sinusoidal source current.

Multicell DC/DC Converter with DSP/CPLD Control. Practical Results

The paper presents practical investigations of DC/DC multilevel, multicell converter with DSP/CPLD control. A flying capacitors topology, natural balancing process and method of control of three-cell DC/DC converter are presented. Practical realization of the controller with use of programmable logic, discrete regulators in signal processor, procedures of initial flying capacitors charging, protection and turn-off the converter are described

The Flywheel Energy Storage with Brushless DC Motor - the Practical Results

This paper presents the results of research of the rotating energy accumulator. In the study the brushless DC motor with permanent magnet (PN=2,98 kW) was used as the motor-generator. The rotating mass made up the steel pipe. This accumulator stored about 4 MJ kinetic energy. The rotation speed was 6000 rpm. The inverter was constructed from intelligent power modules. The control of this one is based on module with FPGA and DSP

Switched Capacitor-Based Power Electronic Converter—Optimization of High Frequency Resonant Circuit Components

This chapter presents issues of optimization of the resonant circuit components’ volume in a switched-capacitor voltage multiplier (SCVM). The SCVM is derived from chip-scale technology but can effectively operate as a power electronic converter in a zero current switching mode when the recharging of switched capacitors occurs in a resonant circuit supported by an inductance. Selection of the passive LC components is not strictly determined, and depends on the optimization strategy according to the volume, efficiency or cost of the converter. Optimization of the volume of LC components is limited by the energy transfer ability via switched capacitors, thus by the rated power of the converter and switching frequency. Depending on the LC values, the converter operates in some specific states that determine the efficiency of the converter and voltage stress on semiconductor switches and diodes. This chapter presents analysis of the converter parameters and operation in the cases of optimization of the resonant circuit components’ values. The analytical discussion is also supported by the simulation and experimental results. All the results are provided for the SCVM but can be useful for a variety of switched-capacitor resonant power converters.

Efficiency Analysis of MOSFET-Based Air-Choke Resonant DC–DC Step-Up Switched-Capacitor Voltage Multipliers

This paper presents the investigation results of the efficiency of power electronic resonant zero-current switching dc–dc switched-capacitor voltage multipliers (SCVMs) in three topologies. The analytical model of efficiency shows the impact of the converters’ particular parameters on their properties and gives indications for an adequate design. The impact of the parameters of the semiconductor devices, parasitic resistances, switched capacitance value, number of switching cells, switching frequency, and choke design on the converters’ efficiency is demonstrated. The converters are investigated analytically with the use of computer-based simulations and experimentally as a three-cell MOSFET-based SCVM dc–dc resonant boost converter. The in-depth analysis and the results obtained are some novel contributions to the existing knowledge of switched-capacitor-based power electronic conversion. Moreover, the presented method of analysis can be useful for analyzing other types of SC power converters comprising resonant switching circuits.

An Analysis Of Overload Conditions In Mosfet-Based Power Resonant DC-DC Step-Up Converters In Switched Capacitor Voltage Multiplier Topology

This paper presents an analysis of operation of resonant DC-DC converter in topology of Switched Capacitor Voltage Multiplier (SCVM) under overload conditions. The SCVM operates as a charge pump, thus the energy transfer rate is limited and depends on the switched capacitance and the switching frequency. However an overload of the converter introduces specific operation conditions that can require a special control. The presented research results have an important significance for selection of components of SCVM as well as switching strategy, because the overload can occur as a result of load decrease as well as during the start of the converter. In the paper analytical, simulation and experimental results are presented for the Mosfet-based 200 Watt SCVM. Streszczenie. W artykule przedstawiono analize mozliwości pracy w stanie przeciązenia ukladu rezonansowego przeksztaltnika mocy DC-DC podwyzszającego napiecie w topologii powielacza napiecie (SCVM – Switched Capacitor Voltage Multiplier). Uklad o przelączanych kondensatorach dzialający na zasadzie pompy ladunku ma ograniczaną moc zdeterminowaną pojemnością przelączanych kondensatorow oraz czestotliwością przelączen. Jednak przeciązenie przeksztaltnika wywoluje specyficzny stan pracy, ktory moze wymagac specjalnego sterowania. Badania mają istotny wplyw na dobor sterowania w ukladzie SCVM, poniewaz przeciązenie moze wystepowac jako skutek wplywu odbiornika, ale rowniez przy starcie ukladu. W artykule przedstawiono badania analityczne, symulacyjne oraz eksperymentalne przeksztaltnika tranzystorowego SCVM z tranzystorami Mosfet, w zakresie mocy do 200 watow. (Analiza stanu przeciązenia przeksztaltnikow rezonansowych DC-DC o przelączanych kondensatorach podwyzszających napiecie zrealizowanych w technice Mosfet w topologii powielacza napiecia). Slowa kluczowe: Przeksztaltnik wielopoziomowy, przeksztaltnik DC-DC, przelączane kondensatory, pompa ladunku