RU2138850C1 - Load simulator for testing controllable switch - Google Patents

Abstract

FIELD: testing electrical equipment containing electronic components; testing switching device distributing DC energy. SUBSTANCE: simulator is connected to busbars of power source in series with switch under test. Simulator is made in form of DC voltage reducing converter whose output is connected in parallel with switch under test. Lead of DC voltage converter output which is similar in polarity is connected to power line. EFFECT: reduced power requirement; reduced requirements for power source. 2 dwg

Description

 The invention relates to the field of electrical engineering and electronics, in particular to the field of testing electrical equipment containing electronic switching elements, and can be used in testing switches that distribute DC energy to consumers.

 When testing equipment (or individual keys) intended for switching power loads, during its manufacturing, certification, during input control, final tests, life tests, etc., incandescent bulbs, LEDs are used to establish the fact of operation (inclusion), to ensure checks of switches at real current - real loads or load equivalents, for example, active resistances of the required rating and power [1]. In addition, current generators can be used as a load, and, if necessary, as load simulators [2].

 In the first case, when switching low currents, especially if the switching element is a relay contact, it is objective enough to check if the bulb or LED is triggered (turned on) [3]. In the second case, the same incandescent bulb can be switched on in parallel with the load equivalent. But this method is not applicable when testing semiconductor switches that commute high power, for which it is important not only the operation (closure) of the switch itself, but also its resistance (power loss in it).

 In any case, a load simulator for testing a controlled key (or the load itself), with one power output connected to one power supply bus, the first input output connected (connected) to the second output of the managed key, and the second output to another power supply bus [1, 4].

 However, the load equivalent must be designed for the maximum power switched by the key (consumed by the load), and have the technological reserve itself to ensure reliable operation for a given resource. At the same time, the larger the current switches one or another key, the more powerful the simulator of the actual load should be, the more keys to be checked in the equipment, the more cumbersome the technological stands for testing become, the more power you need to dissipate safely and the more powerful the power source should be. The problem becomes especially acute when the equipment is installed for long (resource) tests.

 The main goal of the proposal is to reduce the consumption of the load simulator. In addition, a reduction in requirements for the power source is achieved.

 This goal is achieved by the fact that the load simulator for testing a controlled key, with one power output connected to one power supply bus, a first input output connected to a second managed key output, and a second input output to another power supply bus, is made in the form of a step-down DC converter voltage to DC, the output of which is connected in parallel with the controlled key, and the output terminal of the DC / DC converter of the same name in polarity is connected to the power bus oyany.

 In FIG. 1 shows the switching circuits of transistor switches VT1 and VT2 and loads 1 and 2 (Rн1 and Rн2), in FIG. 2 - connection diagrams of simulators 1 and 2 of these loads - step-down voltage converters to the same transistor switches.

In the drawings are indicated:
1, 2 - loads Rн1 and Rн2 - in FIG. 1 and step-down DC-DC converters (load simulators) in FIG. 2. The converters 1 and 2 themselves can be performed according to any scheme. In this case, the output lowering winding of the voltage converter 1 or 2 is connected through a rectifier to the output of the converter. If necessary, the rectifier can be equipped with a filter.

 VT1, VT2 - transistor switches; C, B, E - collector, base, emitter of these keys.

 + E and -E are the power buses of the device containing the tested keys VT1, VT2.

_O + U and -U _O - output voltage converters 1 and 2 and the polarity of their findings.

 Each of the keys VT1 or VT2 as in FIG. 1 and 2, it is connected by one power terminal to the power bus + E or -E, load 1 or 2 is connected between the other power terminal of the tested transistor switch VT1, VT2 and the second power bus.

The output of the DC / DC converter (load simulator) is connected in parallel with the power terminals of the switch, and in both schemes of FIG. 2 to the power bus + E or -E connected the same name by polarity + U _o , -U _o output of the DC / DC converter output. Power currents flow through these circuits (indicated by bold lines).

 The device operates as follows.

 When the key is open, no current flows through it and the voltage on the load (Fig. 1) and on the load simulator (Fig. 2) is zero. In this case, the diodes of the output rectifier of the load simulator are closed. If the output rectifier is equipped with a filter capacitor, then this capacitor is charged to the supply voltage E of the device.

 When the VT1 (or VT2) key is turned on (closed), the circuit forms the bus + E - Rн1 - VT1 - the bus -E (or the bus + E - VT2 - Rн2 - the bus -E), through which the current flows into the load circuit Rн1 through the key ( Fig. 1).

 A similar circuit occurs when the key VT1 (or VT2) in FIG. 2: bus + E - upper terminal of load simulator 1 - lower terminal of load simulator 1 - VT1 key - bus -E (or bus + E - key VT2 - key VT2 - upper terminal of load simulator 2 - lower terminal of load simulator 2 - bus - E).

After the VT1 (or VT2) key is closed and the load simulator is connected to the supply buses, the process of converting a constant supply voltage (from 28 to 120 V of an on-board voltage or more, depending on the type of equipment under control) to a constant voltage U _out = 1-2 V. This voltage is applied to the public key VT1 (or VT2), and a current equal to the rated load current starts flowing through it (provided by the corresponding design of step-down DC-DC converters).

The power of the voltage converter itself (load simulator and power consumption from the power source E) at a rated current through the public key is E / U _output times less than the rated load power switched by this key. So, when the voltage of the on-board power supply is only 28 V, the power consumed from it by the load simulator decreases by at least 10 times. If the simulator is used at high voltages of the on-board network (100 V or more), then the gain can be 50 or more times. With such a reduction in power consumption, the problem of ensuring the safety of large power dissipation can completely disappear and the requirements for a power source are significantly reduced.

 The complication of the load simulator circuit (a voltage converter instead of a conventional resistor, although powerful enough) is justified by reducing the installation power of all equipment by one to two orders of magnitude, reducing the requirements for this equipment in terms of safety, improving the mass-dimensional characteristics of the equipment (instead of stationary installations, you can use portable).

 The proposal is at the preliminary design stage and is supposed to be used at the enterprise in technological stands intended for testing newly developed equipment for the on-board power supply control system.

Sources of information
1. Yu. I. Konev. Energy possibilities of miniaturization of power semiconductor integrated devices. On Sat articles edited by Yu.I. Koneva, issue 4, 1973, p. 3-16, Fig. 1.

 2. G.M. Vedeneev, A.M. Zenchenko, A.B. Tokarev. Power bipolar transistors when working in key modes. Chapter 4. Hardware input and output control and study the characteristics of power transistors. - M.: Publishing House MPEI, 1992, p. 63-77, fig. 4.1, 4.2, 4.6.

 3. A device for monitoring the reliability and life of the relay. Description to copyright certificate of the USSR N 181741, cl. 21g 10/01.

 4. Yu. I. Konev. Energy possibilities of miniaturization of power semiconductor integrated devices. On Sat articles edited by Yu.I. Koneva, issue 4, 1973, p. 3-16, Fig. 7.

Claims (1)

 A load simulator for testing a controlled key, with one power output connected to one bus of a power source, the first input terminal connected to a second terminal of a controlled key, and a second input terminal to another bus of a power source, characterized in that it is made in the form of a step-down DC-DC converter to constant, the output of which is connected in parallel with the controlled key, and the output terminal of the DC-DC to DC converter of the same name is connected to the power bus e.

Images