RU2561230C1 - Test bench of electrical machines in dynamic mode - Google Patents

Abstract

FIELD: electricity.

SUBSTANCE: test bench includes a transformer connected via primary winding to supply mains and via secondary winding to an input of a controlled rectifier, a throttle, one of the outputs of which is connected to the first output bus of the controlled rectifier, and a setting generator. Additionally, it includes a flywheel, a controlled reversible energy converter and a super capacitor connected with one of its outputs to the second output of the throttle, and with the other output to the second output bus of the controlled rectifier. The controlled reversible energy converter is connected with a power input to outputs of the super capacitor and with a control input to the output of the setting generator, and with the output to windings of the test electrical machine, on the shaft of which the flywheel is installed.

EFFECT: improving energy efficiency of test of electrical machines in a dynamic mode.

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Description

The invention relates to electrical engineering and is intended for use in testing electric machines of direct and alternating current.

Known stands for testing electrical machines in dynamic mode, containing a transformer connected by a primary winding to the supply network, and a secondary winding to the input of a controlled rectifier, and a master oscillator (Weiner Α., Mokhnaty Α., Nabok S., Kalashnik S., Khizhnyak B. Post-repair tests of AC motors. Stand for dynamic loading / Electrical News, 2011, No. 2 (68); RF patent No. 2334993, IPC G01R 31/34. - Publish. September 27, 2008; RF patent No. 2133044, IPC G01R 31 / 34; E21C 31/04. - Published on July 10, 1999).

In well-known test benches for testing electrical machines in dynamic mode, a voltage is applied to the stator of the machine, causing the rotor to rotate. The energy state of the engine under test and the power supply network in this case is characterized by energy-exchange processes in the electric machine-network system. When the machine accelerates, electric energy is consumed from the network, while braking the machine, the kinetic energy of the rotating masses is recovered in the power supply network. Since the processes of consumption and recovery take place alternately, such tests are characterized by low energy efficiency. During acceleration mode, a lot of power is consumed, during recovery, the use of return energy leads to an increase in voltage in the load connection unit. In this case, the efficient use of recovered energy is possible only if there is an appropriate power in the receiver network of electric energy.

Therefore, the disadvantage of the known stands for testing electrical machines in dynamic mode is the low energy efficiency.

Of the known technical solutions, the closest to the achieved result to the proposed invention is a stand for testing electrical machines in dynamic mode, containing a transformer connected by a primary winding to the supply network, and a secondary winding to the input of a controlled rectifier, a choke, one of the terminals of which is connected to the first the output bus of the controlled rectifier, and the master oscillator (Rodkin D.I. Systems of dynamic loading and diagnostics of electric motors during after-repair tests. - M.: Nedra, 1992, p. 161, Fig. 9.3).

In known stands for testing electrical machines in dynamic mode, a voltage is applied to the stator of the machine, causing rotational-vibrational motion of the rotor. The energy state of the engine under test and the power supply network in this case is characterized by energy-exchange processes in the electric machine-network system. When the machine accelerates, electric energy is consumed from the network, while braking the machine, the kinetic energy of the rotating masses is recovered in the power supply network. Since the processes of consumption and recovery take place alternately, such tests are characterized by low energy efficiency. During acceleration mode, a lot of power is consumed, during recovery, the use of return energy leads to an increase in voltage in the load connection unit. In this case, the efficient use of recovered energy is possible only if there is an appropriate power in the receiver network of electric energy. The periodic process of energy consumption and recovery causes voltage fluctuations in the network and an increase in electric energy losses.

Therefore, the disadvantage of the known stand for testing electrical machines in dynamic mode is the low energy efficiency.

The aim of the invention is to increase the energy efficiency of testing electrical machines in dynamic mode.

This goal is achieved by the fact that in a well-known stand for testing electrical machines in dynamic mode, containing a transformer connected by a primary winding to the supply network, and a secondary winding to the input of a controlled rectifier, a choke, one of the terminals of which is connected to the first output bus of a controlled rectifier, and a master oscillator, an additional flywheel, a controlled reversible energy converter and a supercapacitor, connected by one output to the second output of the inductor, and by the other output to the second On the output bus of the controlled rectifier, the controlled reversible energy converter is connected by a power input to the terminals of the supercapacitor, the control input is connected to the output of the master oscillator, and the output is connected to the windings of the tested electric machine, on the shaft of which a flywheel is mounted.

Compared with the closest similar technical solution, the proposed method has the following new features:

- flywheel;

- controlled reversible energy converter;

- supercapacitor.

Therefore, the claimed technical solution meets the requirement of "novelty."

When implementing the invention, it is possible to increase the energy efficiency of testing electrical machines in dynamic mode. When testing an electric machine, the rotor is driven back and forth. The power source of the power converter controlling the electric machine is a supercapacitor. During acceleration of an electric machine, electric energy is consumed from the supercapacitor, while braking the machine, the kinetic energy of moving masses is converted into electrical energy, which is accumulated in the supercapacitor. Energy losses during the operation of the electromechanical system in dynamic mode are compensated by recharging the supercapacitor using a controlled rectifier connected to the supply network.

Therefore, the claimed technical solution meets the requirement of "positive effect".

For each distinguishing feature, a search is made for known technical solutions in the field of electrical engineering, automation, and electric drive:

- flywheel;

- controlled reversible energy converter;

- supercapacitor.

Known flywheels in stands for testing electrical machines (RF patent No. 2496100, IPC G01M 17/00. - Published in BI, 10/20/2013). In the known devices and the proposed technical solution, the flywheels are used to create a dynamic load of an electric machine and, therefore, perform similar functions.

Known controlled reversible energy converters in the stands for testing electrical machines (Rodkin DI Systems of dynamic loading and diagnostics of electric motors in after-repair tests. - M .: Nedra, 1992, p. 208, Fig. 11.1). In the known devices and the proposed technical solution, the flywheels are used to create a dynamic load of an electric machine and, therefore, perform similar functions.

Supercapacitors in the known stands for testing electrical machines in dynamic mode were not detected.

Thus, these features provide the claimed technical solution according to the requirement of "significant differences".

The essence of the invention is illustrated by drawings. In FIG. 1 shows a functional diagram of a bench for testing electrical machines in dynamic mode. The drawing indicates: 1 - power supply network; 2 - transformer; 3 - controlled thyristor rectifier; 4 - throttle; 5 - supercapacitor; 6 - master oscillator; 7-controlled reversible energy converter; 8 - electric car; 9 - flywheel.

In the stand for testing electrical machines in dynamic mode, the transformer 2 is connected by the primary winding to the supply network 1, and the secondary winding is connected to the input of the controlled rectifier 3, one of the outputs of the inductor 4 is connected to the first output bus of the controlled rectifier 3, the second output of the inductor is connected to the first output supercapacitor 5, the second terminal of which is connected to the second bus of the controlled rectifier 3, the controlled reversible energy converter 7 is connected by a power input to the terminals of the supercapacitor 5, the control input oedinen yield oscillator 6 and the output connected to windings of an electrical test machine 8, on which the flywheel 9 is mounted shaft.

The stand for testing electrical machines in dynamic mode operates as follows. The supercapacitor 5 connected to the output of the controlled rectifier 3 through the inductor 3, operates in recharge mode. On it, with the help of a controlled rectifier, a constant voltage is maintained. The controlled rectifier is connected to the supply network 1 through a transformer 2. The inductor 4 is designed to reduce the ripple of the charge current of the supercapacitor 5. The master oscillator 6 generates an alternating control voltage for the reversible energy converter 7. The controlled reversible energy converter generates a supply voltage of the motor 8, providing it rotational motion due to the energy stored in the supercapacitor 5. When the motor 8 rotates in one direction, i.e. acceleration to a maximum speed Ω _m , kinetic energy is accumulated in flywheel 9

, $$W_{\mathrm{to}}=\frac{J{\Omega }_m^2}{2}$$

,

where J is the moment of inertia of the flywheel 9.

When the direction of rotation of the engine 8 changes, the braking of the rotating masses occurs and the engine 8 converts the mechanical energy into electrical energy, which returns to the supercapacitor 5. Then the cycle repeats.

The energy losses in the elements of the reversing converter 7 and the motor 8 are compensated by recharging the supercapacitor 5 from the mains 1. Thus, the energy consumption from the mains 1 during testing of the electric machine 8 is determined by the losses in the elements of the stand and is 5 ... 15% of the power of the tested electric cars.

The technical implementation of the reversible energy converter 7 is determined by the type of electric machine. For testing electric DC machines, a bridge transistor converter, the circuit of which is shown in FIG. 2. The device depicted in FIG. 2, contains transistors 10-13 and reverse diodes 14-17. An anchor winding of the DC motor 18 is connected to the output of the reversing converter.

For testing electric AC machines, for example, asynchronous machines, a bridge three-phase transistor inverter, the circuit of which is shown in FIG. 3. The inverter shown in FIG. 3, contains transistors 19-24 and reverse diodes 25-30. A three-phase asynchronous motor 31 is connected to the inverter output.

Thus, the proposed technical solution improves the energy efficiency of the stand due to the fact that the test of electrical machines involves the use of recovered energy when braking rotating masses directly for the subsequent acceleration of the machine with the flywheel 8.

In order to confirm the positive effect achieved by using the proposed technical solution, a simulation of the test system of an induction motor was carried out, implemented according to the scheme of the stand shown in FIG. one.

The parameters of the engine stand had the following meanings.

AC machine (motor):

Power - 400 kW;

Voltage (linear) - 380 V;

Rated rotation speed - 950 rpm;

Thyristor converter: output voltage U = 690 V;

Supercapacitor 100 Φ.

Flywheel with a moment of inertia of 30 kg · m ² .

In FIG. Figure 4 shows the results of modeling a system that implements the proposed bench for testing electrical machines in dynamic mode: a diagram of power consumption, energy consumed and recovered, and flywheel rotation speed.

Cycle time swinging movement T with _q = 8. The mechanical energy consumed by the electric machine in the motor mode is 1.1 MJ. The energy recovered during braking of the machine is 1.0 MJ. The energy consumed from the network per cycle is 0.1 MJ. Thus, the total power of an electric machine operating alternately in motor and generator modes is 500 kW. The power consumed by the stand is 25 kW, i.e. 5% of the power of an electric machine during testing.

Thus, the use in a test bench for electric machines in dynamic mode, containing a transformer connected by a primary winding to the supply network, and a secondary winding to the input of a controlled rectifier, a choke, one of the terminals of which is connected to the first output bus of a controlled rectifier, and a master generator , additionally, a flywheel controlled by a reversible energy converter and a supercapacitor connected by one output to the second output of the inductor, and by the other output to the second output bus of the control trolled rectifier, with controllable bidirectional power converter connected to the power input terminals of the supercapacitor, a control input connected to the output of the master oscillator and the output connected to windings of an electrical machine under test, which is mounted on the shaft flywheel provides increased energy efficiency test.

Using the proposed technical solution for testing electrical machines will increase the technical level and reduce power consumption.

Claims (1)

A stand for testing electrical machines in dynamic mode, containing a transformer connected by a primary winding to the supply network, and a secondary winding to the input of a controlled rectifier, a choke, one of the terminals of which is connected to the first output bus of a controlled rectifier, and a master oscillator, characterized in that additionally introduced a flywheel, a controlled reversible energy converter and a supercapacitor connected by one terminal to the second terminal of the inductor, and by the other terminal to the second output bus rectifier controlled reversible power converter connected to the power input terminals of the supercapacitor, a control input connected to the output of the master oscillator and the output connected to windings of an electrical machine under test, the shaft of which is mounted a flywheel.

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