RU2662791C1 - Local network with different energy sources inverter charging and discharge converter system - Google Patents

Abstract

FIELD: electronic equipment.SUBSTANCE: invention relates to the field of industrial electronics and is intended for creation of the guaranteed uninterruptible power supply system for AC and DC consumers. System contains four sources of electricity (AC industrial network, array of photoelectric converters, gas / gasoline / diesel generator or wind generator, storage battery) and inverter charging and discharge converter system. Inverter charging and discharge converter system consists of a series of converters: bi-directional inverter operating synchronously and in parallel with the industrial AC network through the power distribution device, AC rectifier with power factor correction and tracking of the maximum power taken from the supplying it source (gas / gasoline / diesel fuel generator or wind generator), bidirectional three-port and unidirectional two-port high-frequency DC-DC converters, internal DC bus, controlling controller and information and control bus.EFFECT: provision of guaranteed uninterrupted power supply to AC and DC consumers with reduced number of required for this purpose converters; increase in the entire system reliability and efficiency, increase in the AC and DC consumers uninterrupted operation time from the storage battery and increase in the photoelectric converters array energy use degree.1 cl, 1 dwg

Description

The invention relates to the field of industrial electronics and is intended to build a guaranteed power supply system for AC and DC consumers based on an inverter charge-discharge converter complex that combines four sources of electricity (industrial AC network, an array of photoelectric converters (hereinafter FEP), a gas / gas generator / diesel fuel or wind generator (hereinafter referred to as generator), rechargeable battery (hereinafter referred to as NE energy storage device)).

Known RF patent No. 2503120 ("Solar-powered device", published on December 27, 2013 Bull. No. 36) containing a solar module, a first DC-DC converter, a battery, a second DC-DC converter, a controller and a load. The disadvantages of this device are:

1) the use of two converters with series connection, which leads to low efficiency, the entire system as a whole;

2) the absence of galvanic isolation in the second DC-DC converter;

3) lack of communication with the industrial network or generator in order to ensure the battery charge in bad weather conditions.

Known RF patent No. 2513547 ("Static reversible converter for powering AC and DC consumers, published 04/20/2014 Bull. No. 11), containing the first bidirectional port" input-output "with a battery connected to it, and the second bidirectional port" input-output ”on the side of the AC mains. In inverter operation mode, direct current is supplied from the battery to the first port, and the AC output is removed from the second port. In rectifier mode, AC input power is supplied to the second port, and DC output is removed from the first port. A high-frequency link and a link of an autonomous inverter of industrial frequency are connected between the ports, connected in series. The disadvantages of this converter are:

1) the lack of tracking the point of maximum power generated by the solar cells in the applications of this device in systems with a renewable energy source;

2) the lack of means to connect a gas / gasoline / diesel generator or wind generator;

3) in the inverter mode, in the high frequency link on the low voltage side, there is a significant amount of ripple of the input current, which will require the use of a significant filter capacitive filter at the input.

Closest to the proposed device in technical essence is the "Electric energy storage system based on rechargeable batteries and a supercapacitor with a function to improve the quality of the network" (RF patent No. 2512880, published on 04/10/2014 Bull. No. 10), containing batteries with bidirectional connected to them inverter, inverter control system, storage system control system, storage system contactor, AC mains contactor, AC mains, stand-alone load, supercondition battery sensors, bidirectional inverter of supercapacitors, supercharger precharge module, bidirectional DC inverter, DC contactor, DC network, network quality control module, active quality reducer control system, thyristor switch of compensating capacitors, compensating capacitor bank.

The disadvantages of this system are:

1) the lack of means for tracking the maximum power point when using this accumulation system with solar cells;

2) the lack of means to connect a gas / gasoline / diesel generator or wind generator;

3) the discreteness of the compensation value of the reactive power of the autonomous load;

4) the lack of controls for the voltage equalization system in series-connected cells of the electric energy storage device;

5) lack of remote control and monitoring tools for the entire system;

6) for consumers of a direct current network, a bi-directional inverter is required, which for the organization of galvanic isolation of the direct current network from the alternating current network will require two AC-DC and DC-DC converters connected in series, moreover, AC-DC must be performed with power factor correction, and high-frequency DC-DC converter with isolation.

The aim of the invention is:

1) reduction in the consumption of electric energy from the industrial network due to the electric energy generated by the photovoltaic generator, generator and injected into the NE;

2) increasing the overall efficiency and reliability of the guaranteed power system with heterogeneous energy sources;

3) the smallest number of converters required in the guaranteed power system with heterogeneous energy sources;

4) increasing the degree of use of solar cells due to the return of the power generated by it to other sources and consumers;

5) a significant reduction in the level of ripple current of the battery, which will increase the resource of its performance;

6) increasing the throughput and efficiency of the power line of an industrial AC network.

These goals are achieved due to the fact that:

1) the synchronous operation of the conversion complex is ensured in parallel with the industrial AC network, photomultiplier, generator and NE, and the energy exchange between the NE and the industrial AC network occurs in two directions, from the industrial network to the NE and vice versa;

2) the currents of the industrial and local AC network are monitored and taking into account their nature, the flows of active power and reactive power flows in two directions from the AC network to the internal DC bus and vice versa;

3) in the high-frequency link on one valve set, several functions are simultaneously implemented: increasing the low voltage of the electric energy storage device to the required DC bus voltage level, taking power with tracking the point of maximum power from the photomultiplier and transferring it to the load or NE, regulating the charge processes and regulation of bi-directional energy flow between the internal DC bus and the energy storage.

The conversion complex provides the following functions:

1) tracking the deviation of the energy quality in the industrial network from the set parameters with the subsequent priority of issuing the energy generated by the photomultiplier, the generator and stored in the NE in the local networks of AC and DC consumers;

2) smoothing the consumption peaks and reducing the amount of electric energy consumed from the industrial AC network, due to the energy generated by the photomultiplier, generator and accumulated in the NE;

3) adjustment of the processes of charge and discharge of NEs, control of a voltage equalization system for series-connected NE cells;

4) tracking the maximum power generated by the solar array;

5) energy extraction from the generator with a power factor close to unity, in the range of the generator output frequency of 10 - 100 Hz and tracking the maximum power taken, which allows the use of a hydrocarbon fuel generator with unstable energy parameters or a wind generator in the system;

6) monitoring the phase shift between the current and voltage of the circuit "industrial network - local network of consumers" and, if necessary, compensation of reactive power of consumers in order to improve the quality of energy in the industrial network.

The invention is illustrated by the following drawing, which shows a system of guaranteed power supply of a local network of AC and DC consumers based on an inverter charging-discharge converter complex.

The positions in the drawing indicate: 1 - industrial AC network, 2 - gas / gas / diesel fuel generator or wind generator, 3 - array of photovoltaic converters, 4 - electric energy storage with voltage equalization system (VHF) 4/1 on cells connected in series storage elements, 5 - inverter charging-discharge conversion complex, 6 - local AC network, 7 - AC consumers, 8 - local DC network, 9 - DC consumers 10 - an active rectifier with a control system 10/1, 11 - a three-port bi-directional high-frequency DC-DC converter with a control system 11/1, 12 - a bi-directional AC-DC industrial frequency inverter with a control system 12/1, 13 - a power distribution device, 14 - two-port high-frequency DC-DC converter with a control system 14/1, 15 - DC contactor, 16 - control controller, 17 - internal DC bus, 18 - information control bus, 19 - generator connection port, 20 - connection port mas siva of photovoltaic converters, 21.1 and 21.2 - ports for connecting the electric energy storage device, 22 - port for connecting the control bus to external devices, 23 - port for connecting the converter complex via Ethernet, 24 - port for connecting a local DC network, 25 - port for connecting a local network alternating current, 26 - port for connecting an industrial AC network, 27 - automatic generator start-up system, 28 - power distribution switchgear control bus 13

The proposed inverter charge-discharge conversion complex 5 contains a means of connection:

• DC input port 20 of the positive output of the photomultiplier array 3. The minus output of the photomultiplier array 3 is combined with the negative output of the NE 4;

• ports of “inputs / outputs” of direct current of positive 21.1 and negative 21.2 conclusions of electric energy storage device 4;

• “input” port of alternating current 19 of generator 2 with automatic start system or wind generator;

• bi-directional AC port 26 for connecting an industrial AC network 1. The industrial network may be completely absent, then the converter complex will work in stand-alone mode;

• bidirectional port 25 with connected AC consumers 7, forming their local AC network 6;

• DC output port 24 with connected consumers 9, forming their local DC network 8;

• “I / O” port 22 for controlling external devices;

• port 23, information and control via the Ethernet interface, for combining converting complexes into a local network or connecting to the global Internet.

The inverter charging and discharging converter complex 5 includes: converters 10, 11, 12, 14 connected by a direct current bus 17 and an electric power distribution device 13, which are controlled from one control controller 16 via an information control bus 18.

 Converter 10 is connected with its "input" 10.1 to port 19, and with its "output" 10.2 is connected to the DC bus 17. Converter 11 with its "input" 11.1 is connected to port 20, with its "inputs / outputs" 11.2 and 11.3 connected to ports 21.1 and 21.2, respectively, and with its “input / output” 11.4 is connected to the DC bus 17. The converter 12, with its “input / output” 12.1, is connected to the DC bus 17, and its “input / output” 12.2 is connected to the input 13.1 of the power distribution device 13 Switchgear 13 with its “input / output” 13.2 is connected to port 26, and with its “input / output” 13.3 is connected to port 25. Converter 14 through “input” 14.1 is connected to a DC bus 17, and its “output” 14.2 is connected to a DC network contactor 15. DC network contactor current 15 with its "output" 15.2 is connected through port 24 to the local DC network 8. The control controller 16 integrates all the converters on the information bus 18, and through port 22 it controls the automatic start-up system 27 of the generator and the voltage equalization system 4/1 (CBN ) on the last successive cell turned off the power storage unit 4 and through the port 23 provides communication with the operators via LAN or Internet global network.

Converter 10 is a synchronous semi-controlled rectifier bridge with antiparallel diodes. The converter 10 and its control system 10/1 ensures that the current is generated in such a way that it matches the shape and phase of the voltage coming from the generator 2, rectifies it and stabilizes the voltage on the DC bus 17, thereby maintaining a high power factor at the port input 19, and the output frequency of the voltage of the generator 2 may vary from 10 to 100 Hz. The control system 10/1 of the converter 10 has a built-in power take-off monitoring function that monitors the maximum power point, which allows replacing a hydrocarbon fuel generator with a wind generator.

The Converter 11 is a bridge bi-directional high-frequency inverter controlled by the method of pulse-width and phase regulation, which ensures stabilization of three voltages at the same time: the voltage of the electric energy storage 4, the voltage of the photomultiplier 3, corresponding to the maximum power point and the voltage of the internal DC bus 17

Converter 11 may have 4 directions of energy flow:

1) from the energy storage 4 to the internal DC bus 17, the energy of the photomultiplier 3 is absent. The mode is characteristic of night time;

2) in the energy storage 4 from the internal DC bus 17, the energy of the photomultiplier 3 is absent. The mode is characteristic in cloudy weather or when NE 4 is discharged;

3) from energy storage 4 to the internal DC bus 17 with the addition of photovoltaic power 3. The mode is typical during the peak load of consumers of alternating and direct current;

4) to the energy storage device 4 and to the internal DC bus 17. Power supply to consumers 7, 9 comes only from the photovoltaic converter 3. The mode is typical during a period of low load of AC and DC consumers.

The Converter 12 is a bi-directional bridge inverter of industrial frequency, controlled by pulses modulated by a sinusoidal law, which allows you to adjust the flow of active and reactive power into the AC network of consumers. Converter 12 operates in two modes - inverter and rectifier. In the inverter mode, the converter 12 converts the voltage of the internal DC bus 17 to an alternating voltage synchronized in frequency, phase and amplitude with the voltage of the industrial network. In the rectifier mode, it converts the alternating voltage of the industrial network supplied through the switchgear 13 into a constant stabilized voltage of the internal DC bus 17.

Converter 14 is a bridge high-frequency DC-DC converter, controlled by the phase shift method, and converts the voltage level of the internal DC bus 17 to the required level of consumers 9 of the DC network 8 with voltage stabilization and current limiting modes. The Converter 14 provides galvanic isolation of consumers 9 of the DC network 8 from the DC bus 17.

The electricity distribution device 13 contains switching means and a set of current and voltage sensors for AC networks 1 and 6, and the measured values are transmitted to the control system 12/1 of the converter 12. The electricity distribution device 13 includes a network quality control module, an AC mains contactor and a contactor accumulation systems.

The control controller 16 of the converter complex 5 is a microcontroller and collects and stores information about currents, voltages, emergency situations in the system and sets the settings for stabilizing the parameters of each converter node, as well as transmits and receives data from control operators via port 23.

The invertor charge-discharge conversion complex 5 operates in the following modes:

1. Standby

When voltage is applied to the input of port 26, the industrial AC network 1 is transmitted through the switchgear 13 to consumers 7. Consumers 9 receive energy from the industrial network 1, as well as solar cells 3 and NE 4 through the converter 11, DC bus 17, DC- The DC converter 14, the DC contactor 15 and the local DC network 8. In addition, in this mode, the voltage of the industrial network 1 is monitored and, if it disappears or goes beyond the set permissible limits, the converter 12 changes the voltage of the flow of energy, and consumers 7 of the AC network 6 begin to receive energy from sources 3, and 4. The control system 12/1 of the converter 12 simultaneously reports an emergency mode to the control controller 16, which, based on the amount of energy coming from the photomultiplier 3 and energy in NE 4, can, if necessary, additionally run a generator 2 equipped with an automatic start system 27 (SAP). In normal mode, when the industrial AC network 1 is present and the voltage of the consumers is within acceptable limits, if there is voltage on the photomultiplier 3, the converter 11 continuously feeds the NE 4, making up for energy losses due to self-discharge.

2. The mode of transmission of flows of active and reactive power

In the active power transmission mode, the control system 12/1 of the converter 12 always monitors the amount of power taken from the industrial network 1 and the power consumed by consumers 7. During peak consumption or exceeding the allowed threshold power transmitted from the industrial network to the AC network 6 by the converter 12 introduces, according to a certain algorithm, an additional flow of active power (automatically, or at the command of the operator), compensating for the difference between the necessary and allowed levels of consumption power from the industrial AC network 1 at the expense of sources 3, 4 and 2. The choice of the priority energy source can be set using the control and monitoring program of the converter complex through the control controller 16. In addition, the control program can specify modes with the permission or prohibition of power transmission in industrial AC network 1. With the status set to prohibit the transfer of energy to the industrial AC network 1 and a decrease in the power consumed by the load 7 generated by the converter 1 2 power will also decrease, up to zero. Thus, the conversion complex can reduce the consumption of active power from the industrial network.

In the mode of reactive power transmission, control system 12/1 analyzes the reactive component of the current of consumers 7 and industrial network 1. If the threshold of reactive power in the power transmission line of the industrial network is exceeded, control system 12/1 puts the converter 12 into the mode of generating a reactive power compensation flow such the value that will lead to a decrease in the reactive component of the current in the industrial AC network 1 up to zero or the maximum permissible level. Given the fact that the output circuits of the converters 10, 11, 12 and the input circuit of the converter 14 have capacitances of significant size, which are connected by a DC bus 17, the storage elements are not loaded with short charge-discharge cycles, which will significantly increase the service life of the NE 4.

The mode of adding active power can work in conjunction with the mode of reactive power compensation, provided that the current required to transfer power to the network is less than the maximum output current of the converter 12.

3. Inverter mode.

In this mode, it is assumed that the industrial network 1 is completely absent or does not meet the requirements of consumers 7 and 9. Consumers 7 and 9 of the AC and DC networks receive power from the solar power supply 3, generator 2 or NE 4, through bi-directional converters 10, 11, 12 and 14, respectively. In this case, the power supplied to the load will be limited by the maximum currents set in the converters 12 and 14.

4. Rectifying mode with a charge of electric energy storage

Consumers 7 of AC 6 receive power from the industrial AC 1, and consumers of DC 9 through converters 12 and 14. In this mode, the charge of NE 4 from the industrial AC 1 is allowed. In the event that generator 2 supplies voltage to the port 19 and FEP 3 generate energy, then the charging current of NE 4 through the converter 11 will be distributed from sources 3, 2 and 1, while the priority source will be FEP 3.

Thus, the conversion complex 5 allows under the conditions of a shortage of allocated power and congestion in the supply line of the industrial network 1, to reduce the energy shortage due to sources 3, 4 and 2, to increase the throughput and efficiency of the power line of the industrial AC network 1. In addition, the conversion complex 5 eliminates the use of a separate charger of the electric energy storage device from the photoelectric converter with the function of tracking the maximum power point and two chargers AC sources - industrial network and the generator, which must be used in existing electric energy storage systems.

Claims (1)

An inverter charging-discharge converting complex with dissimilar energy sources for supplying AC and DC consumers, containing a bi-directional two-port inverter, the first port of which is connected to the battery pack, and the second port is connected to the AC bus, a switchgear containing an accumulator contactor, a contactor AC networks, network quality module, DC network contactor, DC consumers network, autonomous load, distinguish which additionally introduces the first bi-directional three-port high-frequency DC-DC converter with a control unit and galvanic isolation of ports, an active rectifier with its own control unit, the second two-port high-frequency DC-DC converter with a control unit and galvanic isolation of ports, a control controller, information and control bus, internal DC bus, and the first DC-DC converter through its first port is connected to an array of photoelectric converters, through the second port is connected with an array of electric energy storage devices, and through the third port it is connected to the internal DC bus, the second DC-DC converter through its first port is connected to the internal DC bus, the second port is connected to the DC output network through the DC network contactor, the bi-directional inverter through its first port is connected to the internal DC bus, the second port of the inverter is connected to the first port of the power switchgear, the second and third port of which are connected respectively with industrial AC network and AC output network of consumers, the first port of the control controller is connected to the information and control bus, which is connected to the control units of the active rectifier, bi-directional three-port DC-DC converter, bi-directional two-port inverter, two-port high-frequency DC-DC converter, the second the port of the control controller is connected to the control inputs of the active voltage equalization system in series-connected cells of the electronic storage device cal energy and automatic generator starting system, and through the third port is an Ethernet interface connection.

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