RU2760979C1 - Device for forming a sawtooth voltage on capacitor - Google Patents

Abstract

FIELD: electrical engineering; converter technology.

SUBSTANCE: device for forming a sawtooth voltage on capacitor belongs to the field of electrical engineering and converter technology and can be used for physical exertion. The invention solves technical problem of forming a bipolar sawtooth voltage on capacitor that is several times higher than voltage of the power source. The device includes a power source, a transistor connected in series to it, an inductance and a capacitor, in parallel to which a series-connected recharging inductance and a limiting resistor are connected.

EFFECT: in steady-state process, due to the dissipation of energy on resistor equal to energy coming from power source during capacitor charge, the voltage amplitudes in capacitor remain constant from cycle to cycle.

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Description

Technology area

The invention relates to the field of electrical engineering and conversion technology and can be used to power physical activities.

State of the art

A device for the resonant charge of a capacitor is known (RF Patent No. 2734903, 10/26/2020 "A device for a resonant charge of a capacitor"), which includes a capacitor of a power supply, 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 limiting transistor. Resonant charge consists of several charge-recharge cycles of a capacitor, the voltage on which rises from cycle to cycle and is several times higher than twice the voltage of the power source. The voltage waveform across the capacitor is sawtooth. When it reaches a predetermined value, the limiting transistor 6 is closed, the last cycle consists only of the interval of recharging the capacitor through the power supply. The charged capacitor is discharged during exercise. This device is taken as a prototype. In the prototype, the shape of the voltage across the capacitor is sawtooth with an amplitude growing from cycle to cycle.

The essence of the invention

The technical problem of the invention is the formation of a sawtooth voltage across a capacitor with constant positive and negative amplitudes up to a voltage several times higher than the voltage of the power source.

To solve this problem, a device for resonant charging of a capacitor is proposed, which includes a capacitor of a power source, to which a series-connected transistor, an inductance and a capacitor are connected, and a series-connected recharge inductance and a resistor are connected in parallel with the capacitor.

Fig 1. Device for resonant charge of a capacitor (prototype).

1 - power supply capacitor, 2 - transistor, 3 - inductance, 4 - capacitor, 5 - recharge inductance, 6 - 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 transistor 2, inductance 3, capacitor 4 are connected, in parallel to which recharge inductance 5 and limiting transistor 6 are connected.

FIG. 2. Timing diagrams of voltages and currents (prototype).

U1 is the control voltage of the transistor 2, U2 is the control voltage of the limiting transistor 6, il is the current flowing through the inductance 3, i2 is the current flowing through the recharge inductance 5, Uc is the voltage across the capacitor 4.

Fig 3. A device for forming a sawtooth voltage across a capacitor.

1 - power supply capacitor, 2 - transistor, 3 - inductance, 4 - capacitor, 5 - recharge inductance, 7 - resistor, Un - power supply voltage.

A device for forming sawtooth current pulses on a capacitor consists of a capacitor of a power source 1, in series with which a transistor 2, an inductance 3, a capacitor 4 are connected, in parallel to which a recharge inductance 5 and a resistor 7 are connected.

FIG. 4. Timing diagrams of voltages and currents.

U1 is the control voltage of the transistor 2, il is the current flowing through the inductance 3, i2 is the current flowing through the recharge inductance 5 and the resistor 7, 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, il is the current flowing through the inductance 3, i2 is the current flowing through the recharge inductance 5, Uc is the voltage across the capacitor 4. Initially, the voltage on the capacitor relative to ground is zero. At the time t = 0, transistor 2 opens, 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 5, limiting resistor 7, but it is much lower than the charging current through capacitor 4 , since the value of the recharge inductance 5 is several times greater than the inductance 3. After the charging current drops to zero and the transistor 2 (t1) is closed, the positively charged capacitor 4 is recharged through the recharge inductance 5 and the limiting resistor 7 to a negative voltage. When overcharged in the resistor 7, part of the energy stored in the capacitor is dissipated. At the moment t2, the transistor 2 opens, the voltages of the power source 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, and the losses in the resistor 7 will also increase. The voltage across the capacitor has a bipolar sawtooth shape with amplitudes growing from cycle to cycle. After several charge-recharge cycles, the voltage amplitude in the capacitor will several times exceed the voltage of the power source, and the energy dissipated in the resistor will equal the energy supplied from the power source to the capacitor, due to which the voltage rise stops, and a steady state occurs.

Thus, in each subsequent cycle of the capacitor charging, energy is introduced into it, which is completely dissipated on the resistor connected in series with the recharge inductance.

Calculations show that with inductance 3 - L = 0.00036 H, recharge inductance 5 - L = 0.015 H, capacitor 4 - C = 0.006 μF, resistor 7 R = 80 Ohm and power supply voltage 60 V, voltage amplitude in capacitor 4 +1570 V and -1470 V, the charging time of the capacitor is 4.8 μs, the recharge time is 21.2 μs.

Claims (1)

A device for forming a sawtooth voltage on a capacitor, including a power supply capacitor, to which a transistor, an inductance and a capacitor are connected in series, a recharge inductance is connected to the connection point of the inductance and the capacitor, characterized in that a resistor is connected in series with the recharge inductance, the second terminal of which is connected to the second capacitor plate.

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