The method of formation of powerful impulses of current in the low impedance load and the device for its implementation

 

(57) Abstract:

The invention relates to power electronics and can be used in devices for testing circuit breakers. Achievable technical result is the reduction of the amplitude of the pulses of the current consumed from the mains supply. In the method of formation of powerful impulses of current in the low impedance load after passing the supply voltage through zero takes place simultaneously with connection of the mains supply to the coils of the primary winding of the transformer connecting the capacitor is charged to voltage selectable from the ratio determined by the ratio of the number of coils which are connected to the capacitor, to the number of turns of the primary winding multiplied by the peak value of the mains voltage. Device for the formation of powerful impulses of current in the low impedance load includes a transformer with a load in the secondary winding, two bi-directional key, a source of alternating voltage, a control device, the capacitor and the device charge. 2 S. p. f-crystals, 8 ill.

The invention relates to power electronics and can be used in devices for testing circuit breakers.

Known embedded winding. The method consists in that the primary winding of the transformer connected to the mains alternating current at an arbitrary time, without synchronization with the supply voltage [1].

However, the known method is characterized by the consumption from the mains supply a large current.

Closest to the proposed by its technical essence is a method, involving the use of a transformer with the load in the secondary winding, characterized by the fact that the primary winding of the transformer connected to the mains supply after a predetermined period of time after passing the supply voltage through zero, i.e. synchronization with mains voltage [2, 3].

However, the known method is characterized by the consumption of the network of large amplitude current pulses.

It is known device for the formation of a powerful current pulse containing the transformer with the load in the secondary winding, bi-directional key and the AC voltage [1]. The pulses of the load current is generated at the circuit bi-directional key, and the key is locked at an arbitrary time, without synchronization with the voltage of AC source voltage.

Closest to the proposed by its technical essence is the device containing the transformer with the load in the secondary winding, bidirectional managed key control device and a source of alternating voltage. The current pulse load generated when the control device bi-directional key, and the key is switched on after a specified period of time after the passage of the voltage of the AC voltage crosses zero, i.e. synchronization with the voltage of AC source voltage [2, 3].

However, the known device is characterized by the consumption from a source of alternating voltage high current.

The objective of the invention is to reduce the amplitude of the pulses of the current consumed from the mains (AC power).

The method is implemented by a device for the formation of powerful impulses of current in the low impedance load, containing the transformer with the load in the secondary winding, bidirectional managed key source of alternating voltage, a control device, the device charge the capacitor and the second bidirectional driven key, and the capacitor is connected through ustroystvo charge - to the source of AC voltage.

In Fig. 1 shows a structural diagram of the device that contains the transformer 1, the secondary winding of which is connected to the load 2, the first bidirectional managed key 3, the first output of which is connected to the first pole of the source of alternating voltage 4, and a second output connected to the first or second output of the primary winding of the transformer 1, capacitor 5, the first output of which is connected to the second pole of the source of alternating voltage 4 and to the third output of the primary winding of the transformer 1, the second bidirectional managed key 6, the first output of which is connected to the second output capacitor 5, and a second output connected to the first or second output of the primary winding of the transformer 1, the unit of charge 7, the inlet of which is connected to the first pole of the source of alternating voltage 4, and the output connected to the second lead of the capacitor 5, the control device 8, the inputs of which are connected to the poles of a source of alternating voltage 4, the first output connected to the first managed key 3, and a second output connected to the second managed key 6.

Device for the formation of powerful impulses of current in the low impedance load running aemula by the formula

< / BR>
where Up. networkm- peak voltage value of the AC power (mains);

W1Cthe number of turns of the primary winding of the transformer connected to the capacitor;

W1P.networkthe number of turns of the primary winding of the transformer, which is connected to the source of alternating voltage (mains supply).

After that, when the voltage of the AC voltage amplitude value corresponding to the minimum drive voltage of the battery 7, the control unit 8 at the same time includes a bidirectional managed keys 3 and 6. Current of the capacitor 5 compensates the reactive component of current of the primary winding of the transformer 1, and therefore the current drawn from the source of alternating voltage 4 and flowing through the bidirectional managed key 3, is significantly less than the current that is consumed from a source of alternating voltage in the absence of the capacitor 5, the second bidirectional managed key 6 and the charging unit 7.

In Fig. 2 shows timing diagrams corresponding to the formation of pulses in the load for the case when W1C= W
Up.network- voltage AC power (mains):

Up.networkm- peak value of the mains voltage;

Uwith- the voltage on the capacitor;

ip.network- current consumption from the mains;

iwith- current of the capacitor;

iw1the current of the primary winding of the transformer (2-th output of the primary winding of the transformer disconnected);

iw2- current of the secondary winding of the transformer;

t1- time to connect pre-charged capacitor and mains supply to the primary winding of the transformer; until time t1the capacitor is charged to the peak value of the mains voltage, after this point, the voltage on the capacitor is equal to the supply voltage.

The essence of the proposed solution is that the reactive component of the current of the primary winding is compensated by the current of the capacitor, and connecting the pre-charged capacitor and mains supply to the primary winding of the transformer it is for the proposed method eliminates current surges and provides already at the initial stage of the process the operation.

The use of the proposed method of forming a powerful pulse of power to the load, with significant inductive component of the impedance of the load, and a transformer having a significant leakage inductance can significantly reduce the amplitude of the pulses of the current consumed from the mains supply.

The possibility of carrying out the invention is confirmed by the results of mathematical modeling of the system circuit simulation Micro-Cap5 firm Spectrum Software. The simulation was performed for three variants of the ratio of the number of turns W1Cand W1P.network. In all embodiments, the power supply frequency 50 Hz; RMS mains voltage 220 V (peak value 310); a cross-section of the iron core of the transformer 50 cm2; the coefficient of magnetic coupling of the transformer 1; load inductance 2 mH; active load resistance 100 ľohm.

The equivalent circuit of the load consists of a connected in series with said inductance and resistance. These parameters correspond to the real values of the device parameters test circuit breakers.

SUB>m). For mathematical modeling was used the scheme shown in Fig. 3. The number of turns of the primary winding W1C= W1P.network= 440, the number of turns of the secondary winding W2= 8, the capacitor C = 1700 international film festival. For condenser was set initial voltage equal to the peak value of the mains voltage (310). For all schemes, characterized by the ratio of the number of turns of the primary winding, the keys K1 and K2 was closed at the time corresponding to the peak value of the mains voltage. In Fig. 4 shows timing diagrams corresponding to the first embodiment, the same designations. The letter "m" on the chart indicates 10-3.

The second variant corresponds to the ratio of W1C= 2W1P.network(Uwith= 2Up. networkm). For mathematical modeling was used the scheme shown in Fig. 5. The number of turns are as follows: W1C= 880, W1P.networkm= 440, W2= 8, the capacitor C = 425 international film festival. For condenser was set initial voltage equal to 2Up. networkm(620). In Fig. 6 are timing diagrams corresponding to the second variant, when the previous notation (current iis that Uwith= 0.5 Up. networkm). For mathematical modeling was used the scheme shown in Fig. 7. The number of turns are as follows: W1C= 220, W1P.network= 440, W2= 8, the capacitance of the capacitor = 6800 UF. For condenser was set initial voltage equal to 0.5 Up. networkm(155). In Fig. 8 are timing diagrams corresponding to the third variant, with the same notation (current iw1specified in Fig. 7).

From the diagrams of Fig. 4, 6, 8 it follows that the use of the proposed method for all three variants of the ratio of the number of turns reduces the amplitude of the pulses of the current consumed from the mains supply, in the same number of times (about 7 times). For all cases with the exception of the capacitor from the circuit, the current drawn from the mains supply will be equal to the current iw1. But you must take into account the following circumstances. With the exception of the capacitor from the circuit of Fig. 5 current iw1will increase about 2 times while maintaining the same current in the load. With the exception of the capacitor from the circuit of Fig. 7 current iw1reduced about 2 times while maintaining the same current in the load.

Literature

1. Musaelyan E. C. Commissioning and testing of electrical equipment electtronica determine currents K3 in electric networks rectified alternating current. JSC "Firm ORGRES".

3. Complete testing device "SATURN, "SATURN-M1. Technical description, operating instructions, passport. - M.: 1993.

1. The method of formation of powerful impulses of current in the low impedance load, consisting in the fact that after a specified period of time after the passage of the supply voltage through zero of the primary winding of the transformer connected to the mains supply, characterized in that simultaneously with the connection of mains supply to the coils of the primary winding of the transformer in the amount of W1n.networkand at the moment of time corresponding to the peak value Un.networkmsupply voltage, connect a capacitor charged to a voltage Uwithto the coils of the same winding in the amount of W1C, and the voltage Uwithchoose from the relation

2. Device for the formation of powerful impulses of current in the low impedance load, containing the transformer with the load in the secondary winding, bidirectional managed key source of alternating voltage and a control device, characterized in that it additionally introduced the device of the charge capacitor and the second bidirectional driven key, and the capacitor pomatia, and through the device of the charge - to the source of AC voltage.

 

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