SU1666933A1 - Loading device of stand for testing combustion engines - Google Patents

Abstract

The aim of the invention is to increase the reliability of the loading device. This goal is achieved in that a device containing an asynchronous balancing machine 1 with a phase rotor, a semiconductor converter 2 with a current sensor 3, a logical switching unit 4, a rotational speed controller 5, a key unit 6, a torque controller 7, a current regulator 8 , a converter control system 9, a torque sensor 10, a registering device 11, a rotational speed sensor 12, a rotor position sensor 13, a running mode selector keys 14 and 15, an electromagnetic torque measurement unit 16 is inserted. The device provides correction control converter 2, depending on the mismatch of the instantaneous and average values of torque, which leads to a reduction of the ripple torque on the motor shaft and, consequently, to increase the reliability of the loading device. 1 il.

Description

The invention relates to the testing of internal combustion engines (ICE), in particular to engine running stands and can be used in load control systems of test stations.

The purpose of the invention is to improve the reliability of the loading device stand

The drawing shows the functional diagram of the device.

The loading device contains an asynchronous balancing machine 1 with a phase rotor, a semiconductor converter 2 with a current sensor 3, a logical switching unit 4, a rotational speed controller 5 connected in series and a key bolt 6, a torque controller 7, a current regulator 8, a converter control system 9 , connected in series tensometric torque sensor 10 and registering device 11, rotational speed sensor 12, rotor position sensor 13, controllable operation keys 14 and 15, electromagnet measurement unit 16 the exact moment of the electric motor.

The device works as follows.

In cold running mode, the logical mode selection signal from the external panel transfers the logical switching unit 4 to the state in which the control key 14 transmits the speed setting signal from the external control panel to the controller 5 input. The key block 6 provides the connection of the controller 5 to the torque controller 7, and the converter control system 9, to the input of which the sensor 13 of the rotor position receives a sequence of pulses with a frequency proportional to the slip frequency of the rotor, ensures the operation of the converter ers 2 in rectifier mode with respect to the electromotive force (EMF) of the rotor and in the inverter mode - to the voltage network, in order to recover energy sliding network. A three-phase alternating network voltage is applied to the stator of the asynchronous machine 1. The loading device operates in motor mode, cranking the engine shaft at a speed at which the signal from sensor 12 is equal to the value of the speed reference signal. The tensometric torque sensor 10 generates a signal proportional to the average torque, the register of which is provided by the device 11. The electromagnetic torque measurement unit 16 produces

signal proportional to the instantaneous value of the moment.

At the next switching of the rotor current, the electromagnetic

of the moment. In this case, the signal from block 16 decreases and the difference between the reference and feedback signals appears at the input of the regulator 7. This leads to an increase in the signal at the output of the regulator 7. which

0 is a reference for re (current stator 8. This increases the signal at the output of the regulator 8, and system 9 provides a change in the control angle of the converter 2, which leads to an increase in current

5 of the rotor and the moment up to the value, with a coir, the feedback signal will be equal to the reference signal. Thus, the variable component of the torque is reduced at each velocity

0 mode. The state of the logical switching unit 4 remains unchanged when the speed is controlled from zero to W0, where W is the synchronous speed of the asynchronous machine. When scrolling speed is reached

The 5 Wo signal from the sensor 12 switches the block 4 to the state when the control system 9 transfers the converter 2 to the inverter mode with respect to the EMF of the rotor and to the rectifying mode to the voltage

0 network, at the same time occur; energizing the asynchronous machine along the rotor circuit, then it works at speeds higher than W0. A decrease in the variable component of the moment at speeds above W0 occurs

5 in a similar way.

In hot running mode, the loading device performs two functions. The signal from the external control panel translates the logical switching side 4 into

0 a state in which the controllable key 14 and the key block 6 provide the signal of the speed reference to the controller 5, and from its output to the input of the controller 7 of the moment. Control system 9 provides operation

5 converter 2 in the rectifying mode with respect to the rotor EMF and in the inverter mode - to the mains voltage. So the device operates in the speed range from 0 to 0.4W0, corresponding to

0 minimally stable engine speed, ensuring the start of the engine.

After starting the engine at W0.4 Wo, the signal from sensor 12 converts the logical switching unit 4 to the state where the control key 14 removes the speed reference. The control key 15 and the key block 6 connect the torque reference signal from the external control panel to the input of the torque controller 7, the Control system 9 converts the converter 2 to the inverter mode relative to the rotor EMF and to the rectifier voltage to the mains voltage. In this case, the asynchronous machine 1 operates in the mode of generator braking with a two-circuit torque control system. The reduction of the variable component of the moment occurs in a similar manner. The mechanical energy of the engine under test is converted into electrical energy and, taking into account the feeding of the rotor, is recovered into the network along the stator circuit minus losses in the electric machine and converter.

When W W0, a signal is transmitted from the logical switching unit 4 to the control system 9, by which it converts the converter to the rectifying mode relative to the EMF of the rotor and to the inverter mode to the mains voltage. The mechanical energy of the tested ICE is converted into electrical energy and minus losses in the asynchronous machine and the converter is returned to the mains through the stator of the machine 1 and converter 2. The loading device operates in generator braking mode with torque stabilization.

The converter control system 9 of all operating modes converts the output signal of the current regulator 8 into the thyristor control pulses of the converter 2 and synchronizes its operation with the network.

The presence of an electromagnetic moment measurement unit connected by one output to an alternating current network, the other to the terminals of the stator windings of the asynchronous machine, and the third to the input of the torque regulator, provides correction for the converter control depending on the instantaneous and average torque values, which leads to reduction of torque pulsations on the engine shaft and, as a result, to increased reliability of the loading device.

Claims (1)

Invention Formula A test bench loading device for testing internal combustion engines, containing a three-phase asynchronous balancer machine with a phase rotor, a semiconductor converter with a current sensor, connected to the rotor winding pins of the asynchronous machine by one output, and to the mains by another, a logic switching unit equipped with an input for connection to an external control panel, a rotational speed controller, a key block with three inputs, a torque controller, the output of which is connected to the first input of the current controller, second 10 whose input is connected to the current sensor output, a converter control circuit, the first input of which is connected to the output of the current controller, the second input of the converter control circuit is connected to the first output of the logic switching unit, and the output of the converter control circuit to the semiconductor converter, torque sensor related to registering 0 by the device, a rotational speed sensor, the output of which is connected to the first input of the logic switching unit and to the first input of the rotational speed controller, the output of which is connected to the first input of the unit 5 keys, a rotor position sensor, connected by its output to the third input of the converter control circuit, the first and second keys of the run-in mode selection, the control inputs of which are connected to 0 to the second output of the logical switching unit, each of the keys of the running-in mode selection is made with an information input for connection to the external control panel, the output of the first selection key 5 of the running mode is connected to the second input of the speed regulator, the second input of the key block is connected to the third output of the logic switching unit, in order to increase the reliability of operation, the device is equipped with an electromagnetic torque measuring unit made with three pins, the first output of the measuring unit is connected to the AC mains, the second output of the measuring unit is connected to the output of the stator winding of the asynchronous machine, and the third output of the measuring unit of the electromagnetic moment is connected to the transducer th entry points in the regulator, the second input of which is coupled 0 with the output of the key block, and the third input of the latter is connected to the output of the second key.