SU884000A1 - Controllable three-phase switching device - Google Patents

Description

The invention relates to an electrical device, in particular, to means of controlling electric motors of direct current. A known three-phase control switch containing three parallel-connected circuits, the terminals of which are intended to be connected to a power source, each of which consists of two transistor terminals and a DZ diode. The disadvantage of this device is the presence of solvents | Other pulsations of the current, which reduces its reliability. The closest to the proposed technical essence and the achieved result is a control three-phase switch, containing an FM1 three parallel-connected circuit whose outputs are intended to be connected to a power source, a pair of which consists of two transistor switches, one of which is shunted; Diodsm, and the point of connection of keys is intended to connect to the load G2}. The disadvantage of this device is its low reliability and functional capabilities. The purpose of the invention is to increase the reliability of the device and the decoding of its fs functions of possibilities. This goal is achieved by the fact that the OIO in the kappa of three parallel-connected circuits is additionally connected with keys, windings of the Drossel and additional diodes, with the windings of the Drossel connected to the secondary diodes and connected parallel to the main diode, and the diodes are connected to the receivers. windings of the throttles and additional key and one of the poods, pre-assigned to be connected to the power source.

FIG. Figure 1 shows the functional scheme of a controlled three-phase switch; in fig. 2 - current diagrams, according to the principle of operation.

The three-phase control switch contains parallel-connected circuits 1–3 connected between the power supply inputs 4 and 5 (first and second respectively). Each circuit consists of a series-connected controller 6 and a transistor switch 7. In parallel with the controller 6, a diode 8 is connected. Each controller contains additional transistor switches 9–11, windings of chokes 12–14, and additional diodes 15–17. The windings of the chokes are wound on the cores 18-20 (according to the number of channels) and with the same numbers have a common core, for example, the windings with number 13 have a common core with number 19, etc. The connecting points of the regulators 6 and transistor switches 7 are connected to the phase 21-23 of the electric machine winding. Additional diodes 15-17 are connected in the opposite direction between the connection point of the additional transistor switches 8-11 and the power output 4.

Managed three-phase switch works as follows.

Additional keys of the regulators 6 and keys 7 include the phases of the windings 21-23 of the electric machine box in accordance with the signals from the rotor position sensor (not indicated). Current regulation takes place through the commutation of additional resistive switches of the regulators 9-11 according to a definite law within the commutation angle. FIG. 2a depicts a diagram of the open state of the additional keys of the regulator and the keys 7, the regulation of the current, and hence the speed, occurs at the frequency IMM f with a period T, and the start of switching on of each of the additional keys 9-11 is separated from each other. the number of channels in the controller, (fig. 2b) Depending on the duration of the connection of the supply network through the additional controller keys (pulse filling factor Kij), the average current in the winding of the electric machine changes. The duration of the pulses is adjusted according to twees

With the control signal and in the general case it may not be the same in different control channels, while ensuring the necessary control mode.

As can be seen from the diagrams (Fig. 2), the current in each canape can be both discontinuous and continuous, and the condition for providing a continuous current can always be fulfilled,

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where f is the electromagnetic time constant of the current path.

Regardless of the nature of the current in the circuit, the total current in the phase of the winding of the core in a wide range of regulation will be indissolubly. The same applies to the current consumed by the switch from the network, which can only be disconnected at K-tm-1, which corresponds to the average current

“SCH-SR-IO.

The frequency of the current ripple in the load and the network is a N times greater than the single-channel regulator of the known device, and the pulse width. negligible due to the shift of the pulses in each channel. This allows a significant reduction in the size of the input filter, or dispense with it.

The use of the invention extends the dynamic range of the DC motor control. This is achieved due to the fact that at low speeds of rotation the effective value of the current does not increase as much as the average value of the current, as it happens in the known device.

Thus, the invention will significantly improve the reliability and extend the functionality.

Claims (2)

1.Ovchinnikov I.V., Lebedev N.I. Contactless DC motors. I., Science 1979, p. 21, 2.Electronic collection of those: Nick in automatics. 1978, no. 10, s. 187.