RU163394U1 - DEVICE FOR AUTOMATIC MAINTENANCE OF BATTERY BATTERY IN ALL CHARGE-DISCHARGE MODES WITH UNINTERRUPTIBLE POWER SUPPLY OF DC CONSUMERS - Google Patents

Abstract

A device for automatic battery maintenance in all charge-discharge modes with uninterruptible power supply for DC consumers, including a transistor galvanically coupled step-up DC voltage stabilizer, a microprocessor control board with a driver and an indication board, characterized in that it further comprises a galvanically coupled transistor connected in parallel step-down stabilizer and series-mounted transistor bidirectional DC / D C converter.

Description

The utility model relates to electrical engineering, to systems of direct (including operational) current of substations and power plants, and in particular to methods of organizing a stabilized DC power supply and systems for its implementation.

One of the characteristic features of DC systems (hereinafter - SPT) is the presence of voltage on the tires of the battery (hereinafter - AB), significantly exceeding the nominal voltage of the system during accelerated and equalizing charges of AB, and for a number of consumers, the voltage supporting battery charge. Ensuring the nominal value of the voltage at the load is achieved by connecting in series with the load of the ballast resistance. Solving the problem in this way has a number of significant drawbacks and reduces the efficiency of the system.

For a number of DC consumers in emergency mode, the voltage level is critical, especially with jerk currents. Jolted currents of oil switches and electric motors of oil pumps lead to a short-term decrease in voltage on the battery. For guaranteed operation of equipment sensitive to undervoltage and voltage dips, it is necessary to stabilize the voltage on the DC busbars (hereinafter - SHPT) equal to 220/110/27 V ± 10% up to the minimum discharge voltage of the battery.

Known technical solutions.

1. Solving the problem of high voltage on AB buses in the modes of supporting and accelerated charges by damping the voltage by connecting the ballast in series with the load.

The disadvantages of this approach:

- quenching diodes used for this purpose have to be installed on a radiator blown by fans to remove heat generated;

- maintaining a constant voltage across the load when changing the voltage level of the battery charge or current consumption (resistance) of the load requires a corresponding change in the number of diodes in the circuit and, therefore, the use of additional voltage-controlled switching equipment;

- the resulting bulky design of the extinguishing unit requires a significant amount of space for its placement in the switchboard cabinet, increasing its overall dimensions;

- unproductive losses of electricity occur;

- there is a need for additional time and labor for the installation of switchboards, its maintenance is complicated.

2. The solution to the problem of voltage drop on the battery in emergency mode with jerk loads.

2.1 The use of elemental switch tail elements AB. Known technical solutions:

http://www.rza.org.ua/elteh/read/208--Elementnie-kommutatori--pereklyuchateli-_208.html;

http://leg.co.ua/knigi/oborudovanie/obsluzhivanie-istochnikov-operativnogo-toka-4.html.

Systems using an elemental switch include a charging motor generator and a charging rectifier. Elemental switch provides constant voltage on the DC bus when charging and discharging batteries. It consists of an insulating plate with contact plates located on it, to which taps from the battery connecting strips are connected. On the plates and the corresponding tires, the discharge and charging brushes slide. They are driven manually or from a small electric motor controlled remotely or using a voltage regulation device (AVR). The change in the number of batteries connected to the DC bus (voltage regulation) occurs without breaking the current circuit and shorting the batteries due to the special design of the switches. In normal operation, with a rechargeable device, the switch bit brush is installed on a given element, which ensures the necessary voltage on the buses. Trailer batteries are not rechargeable. They are used only in case of disappearance of voltage on the substation tires and disconnection of the charging device.

For the formation of plates and deep recharges, a mobile engine-generator is provided, which, if necessary, is delivered to the substation.

A disadvantage of the known technical solutions lies in the various conditions of charge and discharge of the main and additional parts of the battery, as a result of which deep discharges and charges of individual elements of the battery are possible, which reduce the life of the battery.

2.2 The use of a two-channel charging and recharging device or a separate unit for recharging a battery with tail elements.

Known technical solutions:

- Charging unit BP-60-10 (factory Converter Moscow, http://www.convertor-power.ru/bp-60-10.html);

- ZVU (Constant Current System Company, Novosibirsk http://www.systemct.ru/product/product_id/2/);

- UPKA (Tekhelektro ST company Smolensky district, Nagat village. Http://www.techct.ru/product/ypka.html);

- VZP-CCI (NILOM company, Dzerzhinsk. Http://www.nipom.ru/produktsiya/2013-07-31-07-17-03/15-produktsiya/281-sistemy-garantirovannogo-pitaniya-postoyannogo-toka -3).

Circuits with similar devices are used in systems with large jerk loads. In this case, the main charging and recharging device charges the main section of the battery, and the additional device charges the tail of the battery. With this approach, the main and tail parts of the AB are in the same conditions. However, the DC system itself is greatly increasing in size due to the need to use several groups of DC buses, additional switching equipment, an additional charger, which negatively affects the reliability and cost of such solutions.

2.3 The use of transistor, galvanically coupled step-up DC voltage stabilizer (the closest analogue):

- UTSP-M (factory Converter Moscow, http://www.convertor-power.ru/utsp.html);

- SCHPT-S (ElectroConcept manufacturing company, Novosibirsk http://vtzp.ru/products/shpts);

- USPN (Constant Current System Company, Novosibirsk http://www.systemct.ru/product/product_id/11/).

In the given technical solutions in normal mode, the rectifier device converts the alternating voltage to direct and recharges the battery.

In emergency mode, in the power system, when the AC mains disappears, or the rectifier device does not provide the required output voltage level, the UTSP-M, ShchPT-S, USPN converters switch to power from the battery. The voltage on the battery cells during the discharge process may decrease to a threshold value of the discharge voltage. By increasing the voltage, the stabilizers maintain the required level of voltage at the load.

Providing an acceptable voltage level in the battery charge mode from the charger, the solution using boost stabilizers is made by reducing the number of battery cells (102 battery banks and 227.5 V versus 108 battery banks and 240.8 V in the classic circuit for 220 V CT ) Providing a given emergency mode time with this approach requires an increase in the battery capacity, which leads to an increase in the cost of the system as a whole.

In known technical solutions, the short circuit current at the output of the devices should not exceed the nominal value of 15 * In for 5 seconds. This means that in order to ensure selectivity and protect the device itself in the system, it is necessary to use high-speed fuses, which are single-shot devices, which makes the system more expensive and places high demands on the selectivity calculation.

Common disadvantages of the known technical solutions are:

- low reliability;

- the complexity and bulkiness of the system;

- difficulty in maintenance;

- low efficiency;

- lack of current limitation.

The authors were tasked with developing a new circuitry solution for organizing reliable power supply to DC consumers, capable of solving a set of measures to ensure stable voltage on DC buses in all operating modes of various types of batteries.

This problem is solved by a device for automatic battery maintenance in all charge-discharge modes with uninterruptible power supply for DC consumers, including a transistor, galvanically coupled step-up DC voltage stabilizer, a microprocessor control board with a driver and an indication board, characterized in that it additionally contains in parallel mounted transistor galvanically coupled step-down stabilizer and series-mounted trans Source bidirectional DC / DC converter.

The inventive utility model (hereinafter - the Device, the claimed Device) is illustrated by drawings.

In FIG. 1 is a structural diagram of the claimed Device; in FIG. 2, 3 respectively show the traditional scheme of the SPT and the scheme of the SPT with the proposed device. The claimed device consists of:

- IGBT-transistor modules VT1 (step-down stabilizer (step-down DC / DC converter)), VT2 (step-up stabilizer (step-up DC / DC converter)), VT3 (bidirectional DC / DC converter);

- chokes L1, L2, L3;

- capacitors C1, C2, C3;

- bit resistor R1;

- control board with driver A1;

- display board A2.

IGBTs are located on the heatsink. The cooling method is forced. To increase the reliability of operation, it is advisable to install two fans that turn on in overload conditions.

Description of the operation of the claimed device.

1) Operation of the Device in the forward direction.

The input voltage from the rectifier is within acceptable limits, and the load current does not exceed the current limit.

The claimed device is in battery charge mode. At the same time, transistor modules VT2 and VT3 work. The output stabilizes the voltage equal to that set by the operator, based on the type of _battery , according to the formula U _sub.el. * n, where:

U _sub. - charge voltage on the element,

n is the number of AB elements.

2) The operation of the claimed Device in the opposite direction.

When the input voltage is lower than the set value, the device switches to the discharge mode of the battery. In this case, transistors VT3 and VT1 work. Stabilization of voltage on the tires is carried out to a predetermined level of the minimum voltage on the _battery , according to the formula U _min.el. * n, where U _min.el. - minimum discharge voltage AB.

The presence of the VT3 transistor module in the Device circuit, in which the upper key is a step-down and the lower key is a step-up, due to the need to convert the voltage from the battery to the bus power supply without loss of time. The bidirectional DC / DC converter obtained due to this scheme allows, according to a specific setting, to instantly switch from the battery charge mode to the battery discharge mode to the guaranteed power buses with voltage stabilization at a given level.

3) Protection status.

The claimed device is in this state when the load current reaches the value of the set current limit or when the input voltage drops below the set minimum value.

When the load current reaches a value equal to the limiting current, the Device provides stability of the current at the output at the level of the limiting current. In this case, the value of the output voltage is not standardized. The device is in this mode, waiting for a decrease in current, after which it restores normal operation.

Note - In the SPT, the protection in the outgoing lines located in the conditions of overload or short circuit should work in this case.

The claimed device should preferably have a bypass function - providing power to the load, bypassing the stabilizers. Connecting the load via the bypass occurs only when the device protections are activated or its automatic switch Q1 is turned off. The device may have a circuit building the power part N + 1 to increase reliability.

The circuit description in FIG. 1 relates to the claimed Device at 100A, a further increase in the power of the stabilizer occurs by parallel connection of power stamper units.

The main technical characteristics are presented in table 1.

The developed device provides:

1. automatic execution in accordance with the program of the control controller of the following operating modes for the battery charge:

- the supporting battery charge with stabilized voltage and the charge of the battery discharged after emergency switching on by the U method;

- accelerated charge of the battery discharged after emergency power-up by IU, IUI methods;

- equalizing charge of the elements (cans) of the battery;

- charge of a deeply discharged battery;

2. Discharge of the battery to the load in the operating mode to the specified limit.

3. correction of the voltage value of the supporting charge depending on the temperature of the battery;

4. control of exhaust ventilation of the battery room, depending on the voltage of the battery;

5. AB training by discharging and charging a stable current to the load according to a pre-configured program;

6. control of the state of the battery by the value of the discharge current, the voltage of half the battery, temperature and capacity of the battery, calculated in automatic mode during discharge-charge cycles;

7. stabilization of a given voltage level at the load in emergency mode by increasing or decreasing the voltage from the battery;

8. AB protection against deep discharge;

9. limitation of the output current in the case of a short circuit on the load;

10. LED indication of readiness for work, work in the battery charge mode, voltage stabilization at the load, as well as the presence of warnings and malfunctions, with details of all parameters and indications on the central display;

11. maintaining an event log with entering in it all the necessary parameters of the modes of charge, discharge, as well as accidents and warnings;

12. automatic bypass activation in case of an accident with the issuance of a discrete and digital signal;

13. protection triggering when:

- short circuit on the load side (short-circuit current limitation at a given level);

- short circuit on the side of the battery;

- overvoltage on the load side in the battery discharge mode;

- internal malfunction.

An explanation of the relevance of the selected solution.

The main components in building the SPT are:

- rechargeable battery (AB);

- switchboard with protection devices (ЩПТ);

- a rectifier (one or several) to power consumers and charge-charge AB (CDW).

Additional components, some of which have recently claimed the role of the main ones, include insulation measuring systems and voltage stabilization devices.

Consider simplified structural diagrams, including one section of the control panel, one battery and one CDW. A typical circuit is FIG. 2. The proposed scheme is FIG. 3.

Consider the various options for building a SPT based on the given structural diagrams.

To begin with, we determine which protective devices can be used in switchboards if the selective reliable shutdown is observed during overloads and short circuits in the system.

The most attractive and cheap option would be to use circuit breakers as feeders instead of fuses, which proved to be excellent for overloads, but in the case of short circuit there are a number of limitations. Due to the limited breaking current (not more than 10 kA), the use of circuit breakers is possible with a battery capacity not exceeding 1500 Ah (short-circuit current ≈ 10 kA), unless, of course, there is a current limiting device. The use of circuit breakers with standard characteristics as input and sectional protective devices at high short-circuit currents also cannot provide selectivity, but for the reason that the response time becomes less than the trip time. Therefore, for example, two circuit breakers with ratings of 16A and 100A with a current higher than 2000A will trip simultaneously (the trip time (arc break) of the circuit breaker is 16A longer than the protection operation time of the circuit breaker by 100A at a given current). The use of circuit breakers in these circuits is possible only when using electronic protection systems with independent trip units, preferably combined into a single system with set trip priorities, or when using limiting devices that prevent the occurrence of current above the cut-off value at the input or section switch.

It can be seen from the foregoing that the optimal solution when designing a protection system in switchboards is limiting the current in the source, i.e. voltage stabilizer with the possibility of current limitation (in a typical circuit - Fig. 2).

The function of the rectifiers according to the standard scheme (Fig. 2) for constructing an SPT includes a charge and a recharge of batteries. If in the charging mode the accuracy of maintaining the voltage of 1% is sufficient, then when charging a discharged battery with parallel operation on the load, due to the low dynamic resistance of the battery to maintain a charge current of 1%, the accuracy of voltage maintenance should be 0.05%! To ensure the possibility of a charge with a specified degree of accuracy, the charge is carried out either by a separate rectifier without load, or by a rectifier having a separate AB current measurement channel.

It should be noted that a rectifier with such accuracy indicators of voltage and current maintenance, battery charge algorithms are very expensive, especially when you consider that such accuracy is not needed on the load, and the recharge current is much less than the load current.

The proposed circuit (Fig. 3) is characterized in that the rectifier is connected directly to the load, and AB through a special device. The claimed device is an improved device for voltage stabilization - USN reversible type, allowing voltage stabilization (both increase and decrease) in any direction. When discharging the battery, the operation of the claimed Device is no different from the operation of the USN, and the structure of the system is preserved, as in the standard scheme: AB - USN - ЩПТ. In normal operation, the claimed device provides the necessary processes for servicing the battery: recharge, charge, discharge (in a typical circuit, a separate device is used to discharge the battery). The rectifier operates on a load and can be performed according to a simpler scheme that does not have AB maintenance algorithms and high voltage maintenance accuracy. At high capacities, this significantly affects the cost of the rectifier. In the battery charging mode, the battery current is small, and the losses in the device are negligible. The load current bypasses the declared device and does not cause losses, so the device in normal mode can work with natural cooling at any load current and battery capacity. Forced cooling is required only in some modes of discharge or accelerated charge high currents. The application of the proposed promising scheme at high load capacities leads to a significant reduction in losses, an increase in the efficiency of the system, and a decrease in its cost without any decrease in reliability. Since the battery is not in the buffer mode when working with the claimed Device, it is possible to use different types of batteries: acidic, alkaline, lithium-ion and others with their characteristic charge and discharge modes. This is especially true for modern types of lithium-ion batteries with up to 3000 charge-discharge cycles, in contrast to 250-400 cycles for sealed acid batteries. Since lithium-ion batteries are not designed to operate in a buffer mode, their use in a typical switching circuit leads to their rapid failure due to overcharging by a constantly flowing charging current, or due to the constant presence of 60-70% charge time work from the battery is much less than that of a different type of battery.

Based on the foregoing, it can be argued that a solution using the claimed Device is promising for ensuring the organization of reliable power supply to DC consumers.

Claims (1)

A device for automatic battery maintenance in all charge-discharge modes with uninterruptible power supply for DC consumers, including a transistor galvanically coupled step-up DC voltage stabilizer, a microprocessor control board with a driver and an indication board, characterized in that it further comprises a galvanically coupled transistor connected in parallel step-down stabilizer and series-mounted transistor bidirectional DC / D C converter.

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