JPS6058413B2 - Electric dynamometer control device using a wound induction machine - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a control device for an electric dynamometer for driving an internal combustion engine using a wound induction machine or for measuring absorbed power.

Conventionally, cage-type induction machines have large torque and excellent efficiency in a narrow slip range near the synchronous speed, but when the slip changes significantly with respect to the synchronous speed, the efficiency decreases. For this reason, the cage type induction machine is changed to a wound type and the secondary side resistance value is changed to cause the torque characteristic to change proportionally, thereby controlling the driving force or absorbed power.

When such a secondary resistor is used, the resistance loss due to the current flowing through it is treated as heat loss. For this reason, there is a Servius method as a method of regenerating this secondary side power to the commercial power source side.

Even if this is done using an electric or stationary power regeneration system, it becomes complicated and expensive. The present invention was developed in view of this point, and the secondary output circuit of a wound induction machine is opened and closed using an interrupter, and the disconnection ratio is changed to generate torque without causing external resistance loss on the secondary side. Proportional transition of characteristics is performed to achieve high efficiency operation both when driving power to the machine under test, or when absorbing power from the machine under test, that is, when regenerating power on the power supply side. It is something. Fig. 1 is a schematic diagram of an electric dynamometer using a wound induction machine. 1 is the machine under test, 2 is the winding induction machine suspended on a rocking device, and the machine under test 1 is connected to the machine under test by a connector 10. be combined.

Reference numeral 3 denotes a sliding ring which is connected to a brush 4 to derive the secondary output of the rotor of the induction machine 2 and to be opened and closed by an interrupter 5.

The commercial power source 7 and the induction machine 2 are connected via a power switch and a voltage regulator 6. 8 is a spring for measuring torque, and 9 is a torque indication scale.

If the machine under test 1 has a variable speed such as an internal combustion engine, it is necessary to select an induction machine having a number of poles whose synchronous speed is a rotation speed lower than the minimum rotation speed.

By doing so, the induction machine 2 acts as an electric motor to start the internal combustion engine 1 when the slip S below the synchronous speed is positive, and acts as a power generator when the slip S above the synchronous speed is negative. It is possible to absorb the energy and regenerate the electric power to the power source side. FIG. 2 shows an example of the disconnection device 5.

Figure 2a is a schematic diagram showing the principle using a mechanical interrupter as an example.
The three cam plates 12 connected to the electric motor 11 are in contact with the movable contact 13 and the cam plates 12 are in contact with each other within the range of the eccentric angle of the cams, and electrical continuity is established. The time can be changed arbitrarily by adjusting the limit plate 14 up and down. FIG. 2b shows an intermittent waveform of the secondary current generated by the interrupter, and the shaded portion indicates the current value when the circuit is closed. In this case, it is necessary to intermittent the current at the frequency of the secondary side output current or a higher frequency than this, and if this is low, the torque fluctuation will increase, which will interfere with power measurement. It turns out.
FIG. 2C is a schematic diagram of a circuit for current control using a thyristor 15 as an interrupter, and a phase control circuit 16 controls the phase angle of ignition. The controlled current has a current waveform as shown by diagonal lines in FIG. 2d. Figure 3a
The secondary output is passed through a rectifier circuit that includes a smoothing circuit, and the DC current is switched on and off using an interrupter to change the interrupt ratio. In the figure, 17 is a rectifier element,
18 is a smoothing circuit consisting of a smoothing capacitor and an inductance, and 19 is an interrupter. FIG. 3b shows the waveform of the DC current interrupted by the interrupter 19. As described above, the secondary output circuit that is opened and closed by the disconnecting device has a low resistance value that can be ignored with respect to the rotor winding, sliding ring, brush, conductor, etc. of the induction machine 2. This means that no power loss occurs due to resistance in the interrupter at any point in the opening or closing of the circuit, and the average current value can be controlled arbitrarily without loss. be.

Therefore, a variable resistor was connected externally for conventional secondary current control, which caused resistance loss, but the primary side input was reduced by this resistance loss, and the induction machine was operated as a generator. In either case, the power regeneration efficiency and the efficiency with respect to input power when used as a generator can be greatly improved in either case. Particularly in the range of the generator characteristics where slip is negative, there is no limit to the slip frequency and even if it becomes large, the DC output intermittent method including the rectifying element 17 and smoothing circuit 18 shown in FIG. 3a becomes easy. As described above, the present invention controls the current by opening and closing the intermittent device in the secondary output circuit of the wound induction machine and changing the intermittent ratio, so that it can be operated as a motor or as a generator and can be used as a commercial power source. Since power regeneration is performed on the secondary side, there is no need for a complicated and expensive regeneration device to regenerate secondary side power, as in the past, and a simple intermittent device can significantly improve efficiency. This makes it possible to provide an inexpensive electric dynamometer that is easy to operate.

Although the above description relates to a control device for an electric dynamometer using a wound induction machine, this control is not limited to electric dynamometers.

[Brief explanation of the drawing]

Figure 1 is a schematic diagram of control when a wound induction machine is used in an electric dynamometer. 1... Machine under test, 2... Wound induction machine, 5... Intermittent device, 7... Commercial power supply. FIG. 2a is a schematic diagram showing the principle of a mechanical disconnection device. 11...Electric motor, 12...Cam plate, 1
3...Movable contact, 14...Control board b is the waveform of the secondary current due to a, and the shaded area is the current value. c is a wiring diagram of a disconnecting device using a thyristor. 15...
...thyristor, 16...phase control circuit, d is c
In the secondary current waveform, the shaded area is the current value. FIG. 3a is a wiring diagram of a disconnection device on the DC side of a rectifier circuit including a smoothing circuit. 17... Rectifying element, 18.
... Smoothing circuit, 19 ... Intermittent. FIG. 3b is an intermittent waveform on the DC side according to FIG. 3a.

Claims (1)

[Claims] 1. Intermittent the secondary output current at the frequency of the secondary output current of the wound induction machine or a higher frequency,
A control device for an electric dynamometer using a wound type induction machine, characterized in that the driving or absorption power of the machine under test coupled to the induction machine is controlled by changing the intermittent ratio thereof. 2. A control device for an electric dynamometer according to claim 1, characterized in that a phase control device performs phase control on the secondary output current of the wound induction machine. 3. Convert the secondary output of the wound induction machine into a DC current through a rectifier circuit including a smoothing circuit, and intermittent the DC current at the frequency of the secondary output current or a higher frequency, and change the intermittent ratio. A control device for an electric dynamometer using a wound induction machine according to claim 1.