RU2734903C1 - Device for resonance charge of capacitor - Google Patents

Abstract

FIELD: electrical equipment.SUBSTANCE: device for resonance charge of capacitor relates to electrical engineering and conversion equipment and can be used to supply pulse loads. Device includes power supply, in-series connected to it transistor, inductance and capacitor. Rechargeable inductance and limiting transistor are connected in parallel to the capacitor. Due to the capacitor recharging to the voltage of the opposite sign, the charging current amplitudes from the cycle to the cycle increase as to value and thereby increase the energy transferred to the capacitor from the cycle to the cycle and reduce the capacitor charging time.EFFECT: invention solves technical problem of charging capacitor to voltage several times higher than voltage of power supply source, and reduction of charge time.1 cl, 4 dwg

Description

Technology area

The invention relates to the field of electrical engineering and converting technology and can be used to power pulse loads. State of the art

A device for charging supercapacitor batteries is known, which implements the method of resonant charging ("Device for charging supercapacitor batteries" RU 177140 U1 dated 02.14.2017), a simplified diagram of which is shown in Fig. 1. It consists of a capacitor of the power supply 1, transistor 2 and 6 connected to it, capacitor 4, transistors 5 and 7 connected to it, inductance 3 is connected between the common points of transistors 2, 6 and transistors 5, 7 3. The first charging cycle, ( Fig. 2), comes from the capacitor of the power supply 1 through the series circuit transistor 2, inductance 3, transistor 6, capacitor 4. To certain values of the capacitance of the capacitor 4 in the first cycle, it can theoretically be charged to double the voltage of the power supply. Each subsequent cycle of recharging the capacitor 4 occurs in two stages: when the inductance 3 is connected to the capacitor of the power source 1 through transistors 2, 7, energy is accumulated in it, when it is switched to capacitor 4 through transistors 5,6, it is recharged. Over several such cycles, the voltage across the capacitor can be several times the voltage of the power supply. Therefore, this device is accepted as a prototype, although it differs somewhat schematically from the proposed device.

In the prototype, in one charging cycle, a fixed energy is transferred to the capacitor, because the amplitude of the current in the inductance is determined only by the voltage across the input capacitor, which limits the amplitude of the charging current and increases the charging time of the capacitor. In addition, the transistor 2, through which energy is transferred to the inductance, is turned off at maximum current, which leads to increased losses (hard switching of transistors).

The essence of the invention

The technical problem of the invention is to charge the capacitor to a voltage several times higher than the voltage of the power supply and to reduce the charging time. For this, a device for resonant charging of a capacitor is proposed, including a capacitor of a power source, to which a series-connected transistor, an inductance and a capacitor are connected, and in parallel with the capacitor, a series-connected recharge inductance and a limiting transistor are connected.

Description of figures.

FIG. 1. Simplified diagram of the prototype.

1 - power supply capacitor, 2, 5, 6, 7 - transistors, 3 - inductance, 4 - capacitor.

The prototype (Fig. 1) consists of a power supply capacitor 1 to which transistors 2 and 6 are connected in series, a capacitor 4 to which transistors 5 and 7 are connected in series, between the common points of transistors 2, 6 and transistors 5 and 7, inductance 3 is connected ...

FIG. 2. Timing diagrams of currents and voltages and currents of the prototype.

i1 is the current through the inductance, i2 is the current through the capacitor, Uc is the voltage across the output capacitor

The principle of operation of the prototype is as follows (Fig. 2).

In the time interval 0-t1, a current flows through the series-connected transistor 2, inductance 3, transistor 5 and capacitor 4, which charges the capacitor 4 from zero to a certain voltage. In the time interval t1-t2, current flows through the series-connected transistors 2, 7 and inductance 3, while energy is stored in inductance 3, which in the time interval t2-t3 recharges the capacitor 4. During the third and subsequent cycles, the amount of energy transferred to the capacitor is not is changing.

FIG. 3. Device for resonant charging of a capacitor.

1 - power supply capacitor, 2 - transistor, 3 - inductance, 4 - capacitor, 8 - recharge inductance, 9 - limiting transistor, Un - power supply voltage.

The device for resonant charging of the capacitor consists of a capacitor of a power supply 1, in series with which a transistor 2, an inductance 3, a capacitor 4 are connected, in parallel to which a recharge inductance 8 and a limiting transistor 9 are connected.

FIG. 4. Timing diagrams of voltages and currents.

U1 is the control voltage of the transistor 2, U2 is the control voltage of the limiting transistor 9, i1 is the current flowing through the inductance 3, i2 is the current flowing through the recharge inductance 8, Uc is the voltage across the capacitor 4.

Implementation of the invention

The principle of operation of the device is illustrated by timing diagrams (Fig. 4), in which: U1 is the control voltage of the transistor 2, U2 is the voltage, i1 is the current flowing through the inductance 3, i2 is the current flowing through the recharge inductance 8, Uc is the voltage across the capacitor 4. Initially, the voltage across the capacitor relative to ground is zero. At the time t = 0, transistor 2 and the limiting transistor 9 open, the initial charge of the capacitor occurs with a quasi-sinusoidal current pulse along the circuit 1, 2, 3, 4. The current also flows through the circuit recharging inductance 8, limiting the transistor 9, but it is much lower than the charging current through the capacitor 4, since the value of the recharge inductance 8 is several times greater than the inductance 3. After the charging current decreases to zero and the transistor 2 (t1) is closed (soft switching), the positively charged capacitor 4 is recharged through the recharge inductance 5 and the limiting transistor 8 to negative more than twice the voltage of the power supply. The limiting transistor 8 is constantly on until the capacitor 4 is charged to a predetermined voltage. At the moment t2, the transistor 2 opens, the voltages of the power supply and the capacitor are added, the charging current pulse is higher, respectively, higher and the voltage across the capacitor increases during this cycle. The second cycle ends at time t4, while the voltage across the capacitor 4 will increase compared to the first cycle. After several charge-recharge cycles, the voltage across the capacitor will be several times twice the power supply voltage. When it reaches a predetermined value, the limiting transistor 8 is closed, the last cycle consists only of the interval of recharging the capacitor through the power supply (tn-tn + 1). The charged capacitor is discharged during exercise.

Calculations show that with inductance 3 - L = 0.004 H, recharge inductance 5 - L = 0.025 H, capacitor 4 - C = 6 μF after the first cycle, the voltage on capacitor 4 will exceed the voltage of the power supply by 2.51 times, after 5 cycles - 10.2 times, and after 10 cycles - 20.6 times (for the prototype after 5 cycles, 2.23 times, after 10 cycles, 3.16 times).

Thus, in each subsequent cycle of charging the capacitor, more energy is introduced into it compared to the previous cycle. This result is achieved due to the fact that a recharge inductance and a limiting transistor are connected in parallel to the capacitor. Due to this, after a cycle of charging the capacitor, a resonant recharging of the capacitor from positive voltage to negative without energy input occurs from the capacitor of the power supply, and the amplitude of the charging current of each subsequent cycle is determined by the sum of the voltages on the capacitor of the power supply and the voltage on the capacitor increasing from cycle to cycle.

Literature.

1. Utility model to the invention "Device for charging supercapacitor batteries" RU 177140 U1 dated 02.14.2017.

Claims (1)

A device for resonant charging of a capacitor, including a capacitor of a power source, to which a series-connected transistor, an inductance and a capacitor are connected, characterized in that a series-connected recharge inductance and a limiting transistor are connected in parallel with the capacitor.

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