RU2388131C1 - Charging controller - Google Patents

Abstract

FIELD: electricity.

SUBSTANCE: application: in the field of power engineering. Controller of high-temperature battery charging for compensator of power in power transmission line comprises sensor devices and devices of calculation that include memory, besides charging controller comprises model of virtual battery.

EFFECT: increased accuracy and reliability.

10 cl, 7 dwg

Description

FIELD OF THE INVENTION

The present invention relates to energy compensation of high voltage transmission lines. By transmission line it is necessary to understand a conductor for a transmission line or distribution of electrical energy in the range of 3 kV and above, preferably in the range of 10 kV and above. In particular, the invention relates to a device for providing the exchange of electrical energy in a high voltage transmission line. The device comprises a voltage source converter (abbreviated as VSC) and an energy storage device. In particular, the invention relates to controlling means of an energy compensator battery.

BACKGROUND

There are many devices and methods for compensating reactive power in transmission lines. The most typical device contains capacitive means or means of an inductor, which can be controlled to be connected to the transmission line. The connection means may preferably include a switch containing semiconductor elements. The semiconductor elements used in known applications typically include a continuous element, such as a thyristor. These types of reactive power compensators are known as flexible AC transmission systems (FACTS).

A well-known FACTS device is a static compensator (STATCOM). STATCOM contains a voltage source converter (VSC) with an AC side connected to the transmission line and a DC side connected to a temporary electric power storage means, such as a capacitance means. At STATCOM, the output voltage is monitored, which allows the compensator to supply or absorb reactive power from the transmission line. The voltage source converter contains at least six self-switching semiconductor switches, each of which is shunted back by a biased diode connected in parallel.

From US 6,747,370, an energy compensation system using a high temperature secondary battery is known. The purpose of the compensation system is to provide energy storage based on an economical secondary battery that has a function to limit the maximum load, a load balancing function and a quality stabilization function. Known systems include a system for supplying electric energy, a storage system for electric load and electric energy, including a high-temperature secondary battery and an energy conversion system. The batteries are sodium sulfur batteries.

The system is organized at the end of the electricity line. A load is a plant that, under normal operating conditions, is provided with electricity from a power line. In the event of a power supply malfunction, a high-speed switch disconnects the power line, while the power is supplied from the secondary battery. At the same time, the backup generator starts up. Well-known systems with sulfur-sodium batteries show that energy compensation systems provide low power for a long time.

In one operating mode, the battery provides the plant with extra energy during the daytime, while at night, it recharges. In order to provide the plant with uninterrupted power, a system of ten parallel-connected battery modules of 1280 V was organized, each of which has a 500 kW converter. In further embodiments, ten battery modules are connected in parallel in groups with a 5 MW converter. In this embodiment, a spare battery group is organized for use with a high temperature battery circuit. In the event of a malfunction in the battery module, the faulty module is turned off, and the spare group is connected in parallel to the circuit.

From US 6924623 a method and apparatus for assessing the status of a secondary battery is known. The objective of the device and method is a faster and more detailed assessment, in comparison with traditional methods and devices. The known method comprises the steps of changing the charging current and calculating the amount of electricity. The disclosed method is preferably directed to determining the degree of degradation.

SUMMARY OF THE INVENTION

An example of an object of the present invention is to find ways to improve a battery management device for compensating power in an energy transmission line.

This problem is solved in accordance with the invention by means of a control device characterized by the features in independent claim 1 or through a method characterized by the steps of independent claim 9. Preferred embodiments are described in the dependent claims.

According to the invention, the battery management of the power compensator depends on the charge controller. The charge controller comprises a battery model representing a virtual battery, a plurality of sensory and computing means including computer means and a memory means. The virtual battery model contains a model of the physical behavior of the battery, as well as a memory containing historical data such as the internal state of the battery, distribution of chemical components, temperature, current and voltage, and charge state properties (SOC).

The SOC value is estimated by the value of the current obtained from the set of calculations carried out using the virtual battery model of parallel observations. The first value of the voltage curve is calculated by the battery module from the measured current curve. The voltage curve is calculated with many parallel selected current curves, each of which deviates by a small amount from the measured current curve. Each of the thus calculated voltage curves is compared with the current measured voltage curve. When close agreement is reached between the calculated and measured voltage curves, the incoming current curve for the corresponding calculation is selected as the current one.

In accordance with one embodiment of the invention, the power compensator comprises a system for controlling the performance and operation of the power compensator. The control system includes a charge controller for maintaining charging and discharging the energy storage device, respectively. Since the discharging and charging behavior of the sodium / metal chloride chloride is complex, the state of charge (SOC) of the battery cannot be measured with sufficient accuracy. The charge controller therefore contains an SOC module for estimating and predicting the battery level.

The sodium / metal chloride chloride cell contains an electrolyte enclosed in a thin barrier of ceramic material. Outside the barrier, the battery cell contains sodium, which is the first electrode. The second electrode contains a pair of nickel-plated copper electrodes, to which is attached a metal structure stretched into the electrolyte. When the battery is charged or discharged, the reaction front propagates inward from the ceramic barrier. Thus, both discharging and charging processes propagate in the same direction and begin from the ceramic barrier. Due to the many charging and discharging cycles, a plurality of areas may remain inside the cell of the battery, defining the areas of power and areas of weakness. Thus, the SOC module is only able to summarize areas that represent power areas. Thus, the SOC value is current integrated.

The SOC module contains a virtual battery model. A virtual battery model consists of many battery parts representing special relationships of parameters and input quantities. Thus, the virtual battery model contains a model of the measuring part, containing the relationship between voltage, current, temperature and other parameters. Also, the virtual battery model contains part of a model for estimating the current SOC value containing a memory device for history data. The virtual battery model also contains a partial model for predicting future SOC values containing the calculation model. Another part of the model relates to historical data, such as charging events, discharge events, current history, recovery data, and the like.

The main objective of the virtual battery model is to generate the SOC value, which represents the remaining battery capacity. The SOC value can be represented as a percentage of the total battery capacity. Another task of maintaining the battery is to charge and discharge the battery so that overcharging or undercharging never occurs, and that the battery temperature is always kept within an acceptable range.

By using the virtual battery model, the SOC module also predicts the SOC value at a later point in time, depending on the selected energy distribution profile and duration. In the process of using the battery capacity in a power compensation situation, the predicted SOC value and the battery status will show if enough energy is available for predetermined purposes. If, for example, there is a lack of energy in the transmission line, the predicted SOC value and battery status will show if the battery capacity is sufficient to provide energy for a given period of time. This can happen after a malfunction in the power line and before the energy is again provided by other sources, since, for example, during the start-up of the generator. If the amount of generated energy in the power line is exceeded, for example, due to a malfunction, the predicted SOC value and battery status will immediately show whether the battery is capable of receiving energy from the transmission line. Hence the power compensator, in accordance with the invention, is able to provide energy and receive energy from the transmission line in the shortest possible time, in milliseconds, and also in a longer time, in minutes.

In an embodiment of the invention, the control system comprises a plurality of sensors for detecting voltage, current, temperature, and other parameters. For the power source for these sensors, the system contains a power supply module on each battery module. The power supply module is galvanically isolated from earth and contains the same potential as the battery module. The power source may include a fuel cell, a photosensitive cell, a thermoelectric cell, such as a Peltier cell, and others. In an embodiment, the power supply module comprises battery means. To send information to the control system, each sensor can communicate via a wireless system or optical fiber. Each battery may also comprise a central communication device for transmitting information.

In accordance with an embodiment of the invention, a transmission module is arranged on each galvanically isolated battery module. The module contains a radio transmission means, a power source and many transducers with sensors. Also, the interaction module is galvanically isolated, thereby achieving the same potential on it as on the battery module. The module can communicate within a wireless local area network, such as a WLAN or Bluetooth network. Measured values, such as voltage, current, and temperature, are preferably transmitted digitally. To save power consumption, interaction is organized in a short period of time. Thus, the interaction device only needs to be charged with electricity for a small percentage of the time. The interaction may preferably occur within the 2 GHz frequency range. The power source comprises, in one embodiment, a backup battery and electric power supply means. Such an energy supply means may comprise any type of generator configuration, as well as a photosensitive element, a Peltier element, a thermal element, or other devices.

The power compensator in accordance with the invention comprises a voltage source converter and a battery with a short circuit failure mode. Under the failure mode due to a short circuit, it is necessary to understand that in the event of an internal battery error, the electric circuit will remain closed. The failure mode caused by a short circuit may be caused by the internal operation of the battery cell. It may also be caused by a controlled key forming a parallel circuit with the battery element.

Since the battery must be able to exchange energy at any time, it is necessary to organize them in order to backup in case of battery failure. Therefore, batteries in which there is a failure mode caused by an open circuit must be connected in parallel. Batteries in which there is a failure mode caused by a short circuit can be connected in series, thereby achieving a much higher voltage level. In an embodiment of the invention, the battery comprises a high voltage battery including a plurality of battery cells, each of which has a failure mode caused by a short circuit. Many of these batteries, connected in series, will always provide a closed loop and, thus, will be able to provide electricity, even with a faulty battery cell. Many batteries connected in series will also be able to provide high voltage energy in the range of 6 kV and above.

The battery module comprises a thermally insulated box including a plurality of series-connected battery cells. The battery module has two terminals containing electrical circuits in the range of 1.5 kV. By connecting these battery modules in series, a voltage level of 6 kV is achieved. The battery module comprises a local bypass tube containing a heat transfer medium in fluid form. The fluid may be a liquid as well as a gaseous medium.

A criterion for the functioning of the battery, for example, the ability to store and release electricity, is that the temperature inside the battery cell is maintained in the range from 270 to 340 ° C. In operating mode, when the battery is charging or running out of heat, thermal energy is generated inside the battery. In standby mode, however, no heat is generated inside the battery. Thus, in standby mode, heat must be supplied from outside the battery. In operating mode and low currents, additional heating is also provided from outside the battery.

In an embodiment of the invention, the power compensator comprises a temperature controller for maintaining the operating temperature of the battery module. In this way, the temperature controller provides standby heating. The temperature controller includes a conduit for supplying a medium flow for transferring heat through the battery module. The pipeline contains the main loop of the pipeline and at least one means of fluid movement, such as a fan or pump. The piping contains a local piping loop for each battery and provides a corridor for the heat transfer medium. The heat enclosed in the heat transfer medium is transferred to the battery cells by convection.

According to an embodiment of the invention, the local loop of the pipeline comprises a first end for receiving a flow of a gas medium and a second end for discharging an exhaust gas medium. In an embodiment, the gaseous medium contains predominantly air. In addition, the main loop of the pipeline contains an upstream side for supplying hot air and a downstream side for receiving exhaust air. Each first end of each local loop of the pipeline is connected to the side of the ascending main loop of the pipeline. Each second end of each local loop of the pipeline is connected to the downstream side of the main loop of the pipeline. All connections between the main pipe loop and each local pipe loop make up the connecting pipe. The main loop contains at least one fan and heat supply devices. In an embodiment of the invention, the main loop of the conduit is grounded and thus exhibits zero potential. Each local loop of the pipeline shows the same potential as the battery module, which contains the local loop of the pipeline. In further embodiments, each connecting conduit comprises a tube of heat-resistant and electrically insulating material, such as ceramic.

According to an embodiment of the invention, a plurality of series-connected battery means form a series of batteries. Each battery module contains a large number of battery cells, each of which has a voltage in the range of 1.7 to 3.1 V. The cells are connected in sequence to form a battery module, which in one embodiment can have a voltage of about 1.5 kV. In one embodiment, four such battery modules are connected in series with a total voltage of 6 kV. However, in other embodiments, a plurality of batteries are connected in series, setting a voltage in the range of 30-100 kV. The main pipe loop is therefore galvanically separated from the battery string. Connecting pipelines must therefore be made of an electrically insulating, heat-resistant material. In an embodiment, the connecting pipe is made in the form of a ceramic tube.

In further embodiments of the invention, the temperature controller also in the operating mode of the battery module provides cooled air to release heat generated by the battery cells.

In a first aspect of the invention, the object of the invention is achieved by means of a charge controller of a high temperature battery device for power compensation from an electric power transmission line comprising sensor means and computer means including memory means, the charge controller comprising a virtual battery model of the battery means for evaluating the state of the battery charge. In further embodiments of the invention, the battery means comprises a high energy, high temperature sodium chloride / metal battery. In other embodiments, a virtual battery model comprises a physical model of a battery device. In other embodiments, the implementation of the virtual battery model includes an evaluation module for performing a plurality of voltage curve calculations, which is derived from the measured value of the curve and the set of measured current curves configured with a deviation. In other embodiments, the charge controller also comprises a measurement module and a prediction module.

In a second aspect of the invention, the object of the invention is solved by a method of selecting an incoming current curve for assessing the state of charge of a high temperature battery device for power line compensator, the method comprising: providing a virtual battery model for calculating a first voltage curve from a first current curve, calculating a second voltage curve from a second current curve, comparison of the first and second voltage curves with the measured voltage curve, selection as the input current curve, current curve, the result The calculation dates of which are most consistent with comparing stress curves. In further embodiments of the method, the first current curve is a measured current curve. In other embodiments, the second current curve is represented as a measured current curve taking into account the deviation.

BRIEF DESCRIPTION OF THE DRAWINGS

Other features and advantages of the present invention will become more apparent to those skilled in the art from the following detailed description, given the accompanying drawings, in which:

figure 1 is a schematic diagram of a power compensator in accordance with the invention;

FIG. 2 is a side view of a portion of a battery including a plurality of battery modules in accordance with the invention; FIG.

figure 3 - schematic diagram of a power compensator containing a temperature controller and a charge controller;

figure 4 - the main content of the SOC module;

5 is a parallel calculation of the voltage level;

6 is a side view of the battery and temperature controller, and

7 is a further embodiment of a temperature controller.

DETAILED DESCRIPTION OF THE INVENTION

A schematic diagram of a power compensator 1 connected to a power line by means of a transformer 2 is shown in FIG. 1. The power compensator comprises a voltage source converter 4, a capacitor 6, and a battery 5. The power source converter contains twelve self-switching semiconductor switches, each of which is shunted in parallel with a biased diode. The AC side of the voltage source converter is connected to the transformer, and the DC side is connected to the capacitor and the battery.

The battery contains many series-connected modules 7 batteries. In the embodiment shown in FIG. 2, which is part of the battery, four battery modules 7a-7d are arranged in the rack 8. Each battery module has a positive terminal 9 and a negative terminal 10. In the embodiment, each battery module is characterized by a voltage 1500 V, so a battery containing four batteries connected in series has a voltage level of 6 kV. However, there may also be a larger number of batteries connected in series, resulting in a higher voltage level.

The battery contains high-temperature, high-power batteries containing sodium / metal chloride elements with an operating temperature in the range of 270-340 ° C. Each battery module contains a thermally insulated housing containing a plurality of series-connected battery cells. During operation, such as charging or discharging, batteries produce heat. In standby mode, it is necessary to provide heat outside the battery to maintain the operating temperature conditions. Therefore, the temperature module contains a local loop of the pipeline, one of the holes 11 of which is designed to receive the flow of the gas medium, and the second hole 12 is for the output of the exhaust gas medium.

Sodium chloride / metal battery cells are an electrolyte enclosed within a thin ceramic material barrier. When the battery is charging or discharging, the reaction front propagates inward from the ceramic barrier. Thus, both processes, charging and discharging, propagate in the same direction and start from the ceramic barrier. Due to the many charging and discharging cycles, a plurality of areas may remain inside the battery cell, defining the areas of allowable capacity and unacceptable capacity.

In additional embodiments of the invention shown in FIG. 3, the power compensator 1 comprises not only a voltage source converter 4 and a battery 5, but also a temperature controller 13 and a control system 14 comprising a plurality of sensing elements 40, calculation means 41 and a charge controller 15. The charge controller includes a module 16 for evaluating the state of charge of the battery. The temperature controller 13 comprises a conduit for a heat transfer medium. The pipeline comprises a main loop 17 of the pipeline, a local loop 18 located in each battery module, and a plurality of connecting pipelines 19 connected to the main loop and local loops. The temperature controller comprises at least one heating means and a fluid motion module for circulating the heat transfer medium in the pipeline. From here, by circulating the heat transfer medium, heat is supplied through the convection to the batteries through each battery. In the present embodiment, the heat transfer medium contains air, and the fluid movement module comprises a fan.

The SOC module 16, which is part of the charge controller 15, also contains many parts, as shown in FIG. The SOC module contains model 42 of a virtual sodium chloride / metal chloride battery, based on which the SOC value is calculated. The SOC module also comprises a measurement module 43, an estimation module 44, a prediction module 45, and a temperature estimation module 46. Using the temperature evaluation module, the further temperature of the battery is calculated, depending on the further state of charge / discharge. This information can be sent to the temperature controller to preheat or cool the battery module.

One method for estimating the current battery current in accordance with the invention is shown in FIG. Based on the initial value, which can be a measured current value, the corresponding voltage value is calculated based on the virtual battery model. Since the measured current value contains uncertainties, a parallel calculation is performed with the virtual battery model for a plurality of current values deviating by a small value from the measured one. By parallel calculation should be understood the calculation of parallel events. Thus, current calculations can be evaluated sequentially, but, nevertheless, represent a parallel calculation. A small deviation Δ = f (t) is determined and the voltage is calculated, where I, i + Δ ₁ f (t), i + Δ ₂ f (t), ..., i + Δ _n f (t). As a result of the calculation, n voltage curves u ₁ (t) - u _n (t) are obtained, which are compared with the current measured voltage value u _m (t). As the input current curve i _i (t), a current curve is selected that leads to the closest estimate of the current voltage. Despite the fact that in the example presented in figure 5 shows 5 parallel calculations, you can carry out any number of calculations. The method described above in the example leads to setting the bias error of the battery current measurement. By using such a tuning technology, the total current measurement error can also be determined.

6, the temperature controller 13 is schematically divided into a main pipe loop 13 and a common local pipe loop 18. In this embodiment, the local loop of the pipeline detects a high potential, while the main loop detects a zero potential. The connecting tubes that connect the main loop of the pipeline to the local one must not only be electrically insulated, but also able to withstand fluid at a temperature of approximately 300 ° C. The main pipe loop in this embodiment comprises a separate fan 20 and a pipe portion 21 for each battery module. Each part of the pipeline contains a heating element 22 for supplying heat to the battery module. The heat supply module may include a resistive element for connecting to a low voltage power source.

Further development of the temperature controller is shown in Fig.7. In this embodiment, the main loop of the temperature controller also comprises a common heating system 23 comprising a heater 22 and a common fan 20. According to this embodiment, it is also provided for cooling the battery modules. Thus, a cooling loop 25 with a cooler and a common cooling fan 27 are ordered there. The provision of cooling or heating can be selected using the switch valve 28. It is also shown in the embodiment that the heating system includes an additional loop passing through the heat storage device 31. The system also includes a second loop 29 passing through a heat exchange device 32 for exchanging heat with a second hydraulic system 33, which may include coolant from a voltage source converter valve. The heating system also includes an additional loop passing through the second heat exchange device 35 for exchanging heat with the second heating system 34, which may be a room heating system.

Although the scope of the claims of the present invention should not be limited by the presented options for implementation, but may also include options for implementation that are obvious to experts in the given field of technology. For example, the SOC module may include additional measurement modules and calculation tools.

Claims (10)

1. The charge controller (15) of the means (5) of the high-temperature battery for the power compensator (1) in the power line (3), characterized in that the means (5) of the high-temperature battery contains a high-temperature, high-power sodium chloride / metal battery, and also that the charge controller (15) comprises a module (16) for assessing the state of charge of the battery and the fact that said module (16) contains a virtual battery model (42) and an evaluation module (44), the evaluation module being configured to: select a plurality of values of -parallel currents (i (t) + Δ ₁ (t), ..., i ( t) + Δ n (t)), each of which deviates to a small value from the measured current values (i (t)), count of the parallel values current, the corresponding voltage values (u ₁ (t), ..., u _n (t)) using the virtual battery model (42), compare the corresponding voltage values with the current measured voltage value (u _m (t)), select the current value to the closest estimate of the current measured voltage value (u _m (t)), as the current current value (i _i (t)), and evaluate the state of charge of the battery by integrating the current current value (i _i (t)). 2. The charge controller according to claim 1, in which the virtual battery model contains a model of the physical behavior of the battery. 3. The charge controller according to claim 1, in which the model of the virtual battery further comprises a model of the measuring part containing the relationship between voltage, current and temperature. 4. The charge controller according to claim 1 or 2, in which the virtual battery model further comprises a model for estimating the current SOC value, comprising a memory for storing history data. 5. The charge controller according to claim 1 or 2, in which the virtual battery model also contains a model that works with history data, such as charging events, discharge events, current history, recovery data, etc. 6. The charge controller according to claim 1 or 2, in which the charge controller further comprises a measuring module (43) and a prediction module (45). 7. A power compensator (1) for a power line (3) containing a voltage source converter (4) and a battery (5), characterized in that the battery contains a high voltage battery means having a failure mode caused by a short circuit, where an internal battery malfunction, the electrical circuit will remain closed, and the charge controller (15) according to claim 1. 8. The power compensator according to claim 7, in which the compensator further comprises a temperature controller (13) to maintain the temperature within the operating range of the battery. 9. A method for assessing the state of charge of a means (5) of a high-temperature battery containing a high-power, high-temperature sodium chloride / metal battery for a power compensator (1) in a power line (3), characterized by the following steps in which: a plurality of parallel current values are selected (i (t ) + Δ ₁ (t), ..., i (t) + Δ _n (t)), each of which deviates by a small value from the measured current value (i (t)), the corresponding voltage values (u ₁ (t), ..., u _n (t)) using the virtual model (42) batteries, compare the corresponding voltage values with the current measured voltage value (u _m (t)), select the current value leading to the closest estimate of the current measured voltage value (u _m (t)), as the current value (i _i (t) ), evaluate the state of charge of the battery by integrating the current value of the current (i _i (t)). 10. A machine-readable medium containing instructions that, when executed by a processor, prompts the method according to claim 9.

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