LT5805B - Method of electric dualism and device for converting of stochastic energy - Google Patents

Abstract

The invention belongs to renewable energy sources and can be applied to small wind power or hydroelectric plants. Dualism method of electrical systems to convert stochastic energy based on the fact that the wind turbine connects directly to the excitation of permanent magnet synchronous generator, a stochastic power of which is converted by rectifier to the continuous changing voltage power and is used an inverter - (the converter system)-, which, according to the concept of duality of power systems, mentioned electric power converts to the alternating electric power of industrial frequency current system by a transformer provides to the power grid system of the conventional voltage, when running in system power mode and for the receiversand when running in autonomous, autonomous reserved, systematic modes, then from a transformer by rectifier charges the energy storage device (battery) from which by a single channel DC power supply to management system, by another channel - through the intermedia

Description

The invention relates to the field of renewable energy sources and can be applied in low power wind or hydroelectric plants.

Known method and device for converting stochastic electricity such as wind, hydroelectric generator. The unit consists of a wind turbine directly connected to a permanent magnet excitation synchronous generator, rectifier, charger, energy storage device, converter inverter, backup load and control system of these units. The control system controls the switching of the semiconductor elements of the charger according to the voltage of the electrical storage device and the switching voltage of the converter, inverter, standby load, semiconductor elements (see US patent US2007 / 0246943, published 2007-10-25).

This method and the device allow to use the power generated by the wind power station with stochastic parameters. The control system selectively selects the electricity conversion structure according to the generator voltage, so the conversion system converts the stochastic wind generator electricity to conventional parameter electricity, which is supplied to the load and to the required voltage to charge the accumulator. However, the control system used is complex enough and requires a computer with microcontroller and software, which requires highly qualified operational maintenance, which significantly increases its cost. This conversion system cannot be used to operate the wind micro-electric power grid. This conversion system cannot work in system mode. The autonomous mode of operation of this system is inefficient when the energy storage device is fully charged, excess electricity is consumed by the reserve load and is released into the environment in the form of thermal energy. A converter is required to match the DC values of the energy storage device and the inverter. This intermediate adjustment of the power conversion parameters when the conversion system is in stand-alone, stand-by mode reduces the reliability, efficiency and further increase the cost of the conversion system.

Known method and device for converting stochastic electricity such as wind, hydroelectric generator. The unit consists of a wind turbine directly connected to a permanent magnet excitation synchronous generator, rectifier, cycloconverter, inverter, voltage, current sensors and control system. The control system controls the operation of the semiconductor elements of the cycloconverter and the inverter based on data from the voltage, current sensors (see US Patent US2009 / 0189393, published July 30, 2009).

This method and the device allow to use the power generated by the wind power station with stochastic parameters. The electricity generated by the wind turbine generator is converted into stochastic electrical energy which is conventionally supplied to the load. This conversion system can operate in offline mode. This conversion system can supply excess power generated by the wind farm to the power grid and energy storage. This conversion system can operate in stand-alone, systematic mode. However, the control system for the power conversion system is complex, as in the case of the first analogue, which requires a microcontroller computer, complicating the system and significantly increasing its cost, and requires highly qualified operational maintenance. A cycloconverter is required to match the rectifier and inverter DC voltage values. This intermediate adjustment of the power conversion parameters when the conversion system is in stand-alone, stand-by, systematic mode reduces the efficiency, reliability and further increases the cost of the conversion system.

In spite of important drawbacks, due to the similarity of the essential features, this method and device have been adopted as a prototype of a possible invention.

The aim of the invention is to increase the energy conversion efficiency of renewable energy sources by maximizing the use of stochastic electricity generated by renewable electricity sources (eg wind or hydroelectric generator), especially at low wind speeds with wind speed V> 0 m / s, a reliable and competitive electricity conversion system and its management system.

The stated objective is achieved by using an inverter for regulation, which converts the DC power of an alternating-current system into an alternating frequency of an industrial frequency current system, which is supplied by a transformer to the mains of a conventional voltage system. In addition, it charges the transformer from the transformer via a rectifier from which it supplies direct current to the control system via one channel, and to the inverter to the system converter. autonomous, autonomous standby mode, and compares the transformer voltage across the comparator to the reference and differential voltage via the signal builder to control the controller provides power to the inverter through the intermediate storage to control the system converter, stand-alone, stand-by mode.

The said purpose is achieved by the converter consists of a bridge inverter - a constant voltage system to the AC system of the inverter and connected to it the transformer, one of whose secondary winding is connected to the load Z _A and synchronous connecting to supply power to the conventional parameters (eg. 230V , 50Hz), and the other transformer secondary winding is connected via a rectifier bridge to an energy storage device (e.g., a redox storage device or battery) that supplies power to a control system consisting of a pulse generator with its phase regulator, pulse generator, converter-switched circuit L _k - C _k for semiconductor control., And a third transformer secondary winding connected through a rectifier bridge to a comparator and through a control signal builder and controller can regulate the power supply from the energy storage to the converter input circuit when autonomous in standby mode and generates AC industrial frequency power for load Z _a . The parameters of the inverter-system converter-switched circuit L _k - C _k are chosen as follows: a> ² k · L _k · C _k = 1,0

frequency, L _k - inductance of switching circuit, C _k - capacitance of switching circuit, φ _{α -} phase. A schematic diagram of a possible method and device of the invention is shown in FIG. 1, a block diagram is provided in FIG. 2, the operation is illustrated by the characteristics of FIG.

An apparatus for converting stochastic electricity according to the present invention is illustrated in FIG. 1, FIG.

consists of a wind turbine VT (1), which is directly connected to a permanent magnet excitation generator PMSG (2), which, when generating electricity, supplies it via a rectifier Ll (3), a bridge inverter - a DC system to an AC system converter (4) ) with commutating circuit L _k (5), C _k (6), for transformer TR (7) load Z _a (8), for mains ET (9) via rectifier L-2 (10) for capacitor C (11), an EC accumulator (e.g., a battery or Redox energy accumulator) (12) which supplies power to the pulse generator IG (13), their phase regulator FR (14) and the ISK (4) to the semiconductor control pulse generator IF (15) via the rectifier L- 3 (16) for a comparator K (17) which supplies a control signal to the signal generator SF (18). Controller V (19) is controlled by SF (18), controls the power supply from the electricity storage EK (12) via the intermediate storage TK (20) to the bridge inverter, the converter of the DC system to the AC system (4).

The possible method of the invention and the device operate in autonomous mode, systemic mode and autonomous standby mode as follows:

In stand-alone mode, the generator with permanent magnets PMSG (2) directly connected to the wind turbine VT (1) generates a stochastic variable frequency, ac voltage system (U = const., I = var.). electricity is converted by the L-1 (3) rectifier into a DC system (U = const., I = var.), and ISK (4) converts it to a current system (U = var. l = const.) electricity, the voltage and current of which are controlled by the electrical storage device EC (12). The ISK converts the converted electricity TR (7) into a conventional parameter (50Hz, 230V) and supplies it with a load Z _A (8), while the excess electricity TR (7) converts and converts it into a direct current using rectifier L-2 (10). electricity, C (11) balances the current and voltage ripple and supplies it to the EC (12). The EK (12) is controlled by a circuit of a comparator K (17), a signal generator SF (18), a controller V (19) which controls the power supply from the energy storage EK (12) to the TK (20). The AC (AC) transforms the AC power, converts it to the DC voltage using the L-3 (16) rectifier, compares the controller V (19) in the comparator K (17) with the reference and differential voltage via the signal generator SF (18). The power supply unit EK (12) supplies electricity to the inverter-system converter ISK (4) via the intermediate storage unit TK (20). When the DC voltage of rectifier L-3 (16) is less than the reference voltage set in comparator K (17), the control circuit activates the power supply of EC (12) via TK (20) to inverter-system converter ISK (4) when rectifier L- 3 (16) terminal voltage higher than the reference voltage, the control circuit shuts off the EC (12) power supply via the TK (20) to the inverter - system converter. The TK (20) supplies constant voltage voltage when the EK (12) is disconnected from the ISK (4) input circuit. A circuit consisting of a phase regulator FR (14) of a pulse generator IG (13), a pulse generator IF (15) controls the switching of the semiconductor elements of the ISK (4) by switching the circuit L _k (5), C _k (6). The pulse sequence of the pulse generation-control circuit is chosen such that the ISK (4) converts the DC voltage system (U = const., I = var.) Energy into the AC system (U = var., I = const.) Electrical energy, with a frequency of 50 Hz. In system mode, the power grid is connected to the TR (7). Excess electricity is supplied through the conversion system to the mains ET (9) or to the load disconnection Z _A (8) ET transforms the AC power through the transformer TR (7) via the rectifier L-2 (10), C (11). converts to direct current electricity and supplies it to an energy storage EC (12).

In stand-by mode, the PMSG (2) generator with permanent magnets is disconnected from Ll (3). The EK (12) supplies direct current via a conversion system for the load Z _A (8).

The operation of the possible method and device of the invention is illustrated by the characteristics shown in Fig. 3. The autonomous mode of operation of the conversion system with the energy storage only is illustrated by the dependence of the voltage Ui and the current Ii of the ISK output terminals on the wind speed V. When V> 0 m / s, Ui> U _E k, Ii> 0. Therefore, the energy storage device is charged with a current Ii with varying wind speed V over a wide range. The autonomous mode of operation of the conversion system with load and energy storage device is illustrated by ISK load voltages U _a and current I _a , electricity storage device charging current I _{EK as a} function of wind speed V. When V> 0 m / s, U _a = const., I _a , ^> 0- Conventionally, therefore, power can be supplied to the load and excess power to the EC. The systemic mode of operation is illustrated by the dependence of the supply currents I _E t, the load voltage U _a on the wind speed V. When V> 0 m / s, U _a = const, U ₃ > U _E t, Iet> 0. Therefore conventional power can be supplied to the load and excess electricity to the power grid. The conversion system can operate in standby standby mode with V = 0 m / s or the wind farm disconnected from the conversion system. From the EC through the conversion system, conventional parameters of electricity can be supplied to the load.

The present invention, compared to a prototype, improves the energy conversion efficiency of renewable energy sources by maximizing the potential of stochastic energy, utilizing an uncomplicated and competitive conversion system and its management system because:

- the conversion system converts stochastic electricity into conventionally defined power according to the dual system concept of electrical systems and supplies it to the load, to the grid and to the corresponding voltage value for the energy storage device at V> 0m / s.

- the conversion system is multifunctional, reliable and straightforward, only one inverter is needed to convert stochastic electricity to conventional power - system converter ISK, converter not needed for constant voltage values, cycloconverter;

- the conversion system is operated using a simple and reliable control system which does not require a software computer

Claims (2)

DEFINITION OF INVENTION 1. The dual system of electrical systems for converting stochastic energy is based on the fact that the wind turbine is directly connected to a synchronous generator of permanent excitation magnets, which converts stochastic electricity into a rectifier with constant voltage and regulates it by means of an inverter. a converter that converts the DC power of an alternating-current system into an alternating current of an industrial frequency system, which is supplied by a transformer to a conventional voltage system mains when operating in system mode and to electric receivers when operating in stand-alone, standby mode , in systemic modes, it also charges the transformer through a rectifier with an energy storage device (battery) from which one channel of direct current electricity supplies power to the control system through another channel via the intermediate storage device, to the inverter to the system converter for autonomous standby operation, and compares the transformer voltage across the comparator to the reference and differential voltage via the signal builder controls the controller which supplies the battery inverter - system converter, autonomous, autonomous standby control. 2. Electrical system dualism unit for converting stochastic energy, consisting of a wind turbine directly coupled to a permanent magnet excitation synchronous generator, rectifier and converter, characterized in that the converter consists of a bridge inverter - DC system to an AC system converter and a transformer connected thereto having one of its secondary windings connected to a load Z _a and capable of supplying electrical power to the grid of conventional parameters via _a synchronous connection, and the other transformer secondary winding connected via a rectifier bridge to an energy storage device supplying power to a control system consisting of a pulse generator phase regulator and pulse generator, converter-switched loop L _k - C _k , for semiconductor control, and the third transformer secondary winding is connected via a rectifier bridge to the comparator and via a control signal for the controller and controller can regulate the power supply from the power storage device to the converter input circuit when operating in stand-alone, stand-by mode and generating AC industrial frequency power for load Z _a and inverter-system converter-switched circuit L _k - C _k as follows: a> ² k L _k C _k = 1.0 for Z _a = Z _a -e ^J ^ °; co ² k · L _k -C _k > 1.0 for z "= z" ,.! Ψα ^{> ΰ} . ^ω ί ' ^L k' ^c k ^<1 = ° ' ^{when z} a = ^z ae ^, in addition, m _k = 2-7i-f _k , where f _{k is the} electric frequency, <a _k is the electric angular frequency, L _k -inductance of the switching circuit, C _k capacitance of the switching circuit, φ _α -phase.