SU455431A1 - Three-phase inverter control device - Google Patents

Description

one

The invention relates to devices for controlling three-phase inverters used in power supply and electric drive systems.

The known control devices are executed on three triggers with divided inputs connected by a ring scaler. The disadvantage of such devices is the possibility of the occurrence of a false mode of operation with simultaneous switching of triggers at the triple frequency when receiving external interference.

The purpose of the invention is to improve noise immunity and simplify the device by introducing a differentiating chain between the output of one shoulder of one phase trigger, the input of the same shoulder of another phase trigger and the input of the opposite shoulder of the third phase trigger.

The invention is shown in FIG. one.

The device contains three triggers Ti, T2 and Tz, interconnected with the master oscillator through the six two-input coincidence circuits of the SS in the usual ring scaling circuit. The trigger output Tj is connected to the trigger inputs T0 and T3 through a DC differentiating chain.

The switching of each trigger occurs after a / 6 period of the three-phase output voltage. At the time of trigger switching

TI triggers TS and Tz must be in a certain state. For example, when the left shoulder of the trigger TI goes into the open state, the left shoulder of the trigger To must be in the closed state, and the left shoulder of the trigger Tz in the open. The differential chain of the DC at the moment of switching the trigger TI supplies to the input of the triggers T2 and Tz such commands that set the triggers to the required state. If at the moment the differential pulse arrives, the TS and Tz triggers are already in the required state, then their state will not change when exposed to pulses. If

5 triggers under the influence of interference start to switch simultaneously, a differential pulse keeps trigger Td from simultaneous switching with trigger T, i.e. it prohibits this abnormal mode

0 device operation.

From FIG. 2a, it can be seen that when a differentiating impulse / d arrives at time t, the flip-flops Ta and Tz are set in the state corresponding to the three-phase t5 / t ,, UT. and t / TsV in the case of a device failure in the triple frequency mode (Fig. 2, b) under the influence of external interference at time ti, the first differentiating impulse U after the moment /, introduces

0 device in normal operation. 3 G1 j) with d g e g and 3 b a s t s n A device for controlling a three-phase inverter, performed on three triggers on a ring scaling circuit, characterized in that, in order to simplify and improve noise immunity, the output of one of the arms the trigger of one phase is connected via a differentiating chain to the input of the same trigger arm of the other phase and the input of the opposite shoulder of the third phase trigger.