RU161785U1 - DC VOLTAGE STABILIZER - Google Patents

Abstract

A DC voltage stabilization device comprising a galvanically coupled step-up DC voltage stabilizer, a microprocessor control board, a driver board and an indication board, characterized in that it further comprises a series-mounted galvanically coupled step-down stabilizer, each stabilizer including a choke and an IGBT transistor.

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 (NIPOM 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 an inexpensive, galvanically coupled DC stabilizer of the raising and lowering type for the organization of reliable power supply to DC consumers.

This problem is solved by a DC voltage stabilization device (hereinafter - USPN), including a galvanically coupled step-up DC voltage stabilizer, a microprocessor control board, a driver board, and an indication board, which, according to the proposal, additionally contains a series-mounted galvanically connected step-down stabilizer, each The stabilizer includes a choke and an IGBT transistor.

The inventive utility model is illustrated in the drawing.

In FIG. The structural scheme of USPN is presented.

USPN consists of series-connected step-up and step-down stabilizers. Each stabilizer includes a choke (L1, L2) and an IGBT transistor (VT1, VT2).

USPN also includes:

- driver board A2;

- control board A1;

- display board A3.

IGBTs are located on the heatsink. The cooling method is forced. To increase the reliability of operation, two fans are required, which are switched on in overload modes.

The USPN design includes contactors that provide switching from the Bypass mode (KM1 - on, KM2 - off) to the output voltage stabilization mode (KM1 - off, KM2 - on).

USPN works as follows.

The input DC voltage is supplied to the terminals XT1: 1, 2 USPN and then through the circuit breaker to the raising and lowering stabilizers. The output voltage is removed from the terminals XT1: 3, 4.

Using the “dry” contacts of the USPN XT2: 1, 2, a signal about the status of the automatic Q1 circuit breaker is sent to the ACS SPT, and the contacts XT2: 3, 4 are used to turn on / off the bypass function.

USPN can be in two states, each of which has two operating modes.

The state of normal functioning.

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

When the value of the input voltage is higher than the specified value of the output voltage, the USPN is in the mode of undervoltage. In this case, the step-down stabilizer operates in pulse width modulation (PWM) mode.

When the magnitude of the input voltage is lower than the set value of the output voltage, the USPN is in the voltage increase mode. The step-up stabilizer operates in PWM mode, and the step-down stabilizer is in the "public key" mode.

Protection Status.

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

When the load current reaches a value equal to the limiting current, the stabilizer ensures stability of the output current at the current limiting level. In this case, the value of the output voltage is not standardized. The presence of the stabilizer in this mode is signaled by the “Current Limit” LED on the front panel of the USN unit. The device is in this mode, waiting for a decrease in current, after which it restores normal operation.

Note: at the same time, the protection in the outgoing lines, which are in conditions of overload or short circuit (short circuit), should work.

When the input voltage decreases to the set minimum voltage value of the battery, the LED "Protection of the battery from deep discharge" on the front panel of the USN unit lights up. This is done to provide an early warning of protection. Protection is triggered when the input voltage drops below the minimum voltage of the battery by 6 V - the stabilizer reduces the discharge current of the battery. The voltage on the battery will be maintained at the minimum acceptable level. The value of the output voltage in this mode of operation is not standardized. The stabilizer can be in this mode for a long time, waiting for an increase in the input voltage, after which it restores normal operation.

USPN has a “bypass” function - providing power to the load, bypassing the stabilizers. The load is connected via the bypass only when the protection of the USPN is activated or its automatic circuit breaker Q1 is turned off. The bypass function is enabled automatically by disconnecting the KM2 contactor and turning on the KM1 contactor.

The description of the circuit in Figure 1 refers to a 100 A stabilizer, a further increase in the stabilizer power occurs by parallel connection of power stamper units.

The main technical characteristics are presented in table 1.

The advantages of the developed device ensure the achievement of the following technical result:

- stabilization of the DC output voltage at a predetermined level by both lowering and increasing the input voltage (there is no need to disconnect consumers sensitive to increased voltage during accelerated battery charge modes, as well as compensation for voltage dips in emergency mode);

- protection of rechargeable batteries from a discharge below a set limit (there is no need to additionally install a DC contactor and its control system to protect the battery from a discharge below a set limit);

- providing selective shutdown of protection devices in a direct current system (achieved by stabilizing short-circuit current at the level of 2, 3 times from the nominal value. Therefore, the need to use fusible inserts disappears, it becomes possible to build selectivity on circuit breakers, which simplifies and cheapens SPT service);

- the lack of strict limits on the number of AB cans (it is possible to vary the number of elements and AB capacity to select the optimal ratio for cost);

- the ability to directly connect the battery to the DC system in the event of a stabilizer failure;

- joint work with insulation control systems (as it is galvanically connected);

- the ability to build redundancy scheme N + 1 to increase reliability.

Claims (1)

A DC voltage stabilization device comprising a galvanically coupled step-up DC voltage stabilizer, a microprocessor control board, a driver board and an indication board, characterized in that it further comprises a series-mounted galvanically coupled step-down stabilizer, each stabilizer including a choke and an IGBT transistor.

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