RU213621U1 - Bidirectional voltage converter with coupled chokes - Google Patents

Abstract

The utility model relates to DC or AC converters, to voltage sources and can be used in mobile vehicles, including electric vehicles, in consumer electronics for powering or charging batteries, in portable devices, autonomous power plants, as well as in industrial electronics for powering various consumer types. The technical result consists in reducing the level of high-frequency oscillations at the input and output of the converter module due to the presence of a magnetic connection between the chokes, which also improves the electromagnetic compatibility of this device with consumers connected to it and its common supply network, reduces the dimensions of the converter and leads to a decrease in the maximum current amplitude in chokes and transistors of the converter. Bidirectional voltage converter with coupled chokes, consisting of two transistors, a control circuit, three capacitors and two chokes, characterized in that the two chokes are galvanically and magnetically connected to each other and are located on the same core. 7 ill.

Description

The utility model relates to DC or AC converters, to voltage sources and can be used in mobile vehicles, including electric vehicles, in consumer electronics for powering or charging batteries, in portable devices, autonomous power plants, as well as in industrial electronics for powering various consumer types.

Technical solutions for lowering the output voltage are widespread (Meleshin V.I., Transistor Converter Technology, M, Technosphere, 2005, p. 229), such as step-down converters consisting of a transistor, diode, inductor and capacitor (Fig. 1a ). In this case, during the opening of transistor 1, the current flows through it to the load connected to point V2, simultaneously accumulating energy in inductor 3 and capacitor 4. After closing 1, inductor 3 gives off energy, trying to maintain the value of the current and its direction, diode 2 closes the circuit and the current continues to flow through the “2-3-4-load” circuit, while the voltage at the output of this converter will be proportional to the opening time of transistor 1.

There are also more advanced schemes of step-down voltage converters (Fig. 1b), where diode 2 is replaced by transistor 1. This solution allows you to increase the efficiency and allows for bidirectional energy transfer, from input to output (V1-V-2) or from output to input (V2-V1).

Such voltage converters are also known (Meleshin V.I., Transistor converter technology, M, Technosphere, 2005, p. 234), as boosters. The simplest of which consist of the same set of components as lower ones, i.e. transistor, diode, capacitor, inductor (Fig. 2a). This device works as follows:

At the moment V1 is energized, capacitor 4 is at potential VI minus the forward voltage drop across diode 2, because the current passes through inductor 3 and diode 2. The control device sends a signal to the gate of transistor 1. Transistor 1 opens and it turns out that the circuit closes, inductor 3 is connected to the power source and begins to accumulate energy. No current flows through diode 2, because the potential at the cathode is higher than the potential at the anode. Then transistor 1 turns off. At this point, inductor 3 seeks to maintain the current value by increasing the potential. At the input of the inductor 3, the potential is still the same - VI, and therefore the potential rises at the point "3-drain 1-anode 2". When the potential at this point becomes greater than the potential at the cathode diode 2, the current will begin to flow through diode 2 to the load and charge capacitor 4 in parallel. At this stage, the circuit also closes, but not through transistor 1, but through the path “3-1 -4-load". To improve the efficiency, diode 2 is replaced by transistor 1 (Fig. 2b).

The main disadvantage of such step-up and step-down converters is the increased level of voltage ripple at the input and output of the module, which leads to the need to use massive input and output LC filters. These ripples worsen the electromagnetic compatibility of the converters with the consumers of the output voltage and the supply network. Also, diode converters cannot be used for bidirectional power transfer from input to output and from output to input.

Closest to the proposed utility model is a switchable DC-DC converter Kappa with continuous input and output current (US 10797593, publ. 06/10/2020). It consists of two transistor switches, a control circuit, two chokes for each arm and a capacitor between them. The Carr converter, depending on the control scheme, can operate in both buck and boost modes.

In this converter, the chokes perform the dual function of both an energy storage element and a filter element. This feature reduces the ripple at the input and output of the voltage converter, which in turn reduces the amplitude of interference in the fundamental range, and also improves the EMC of the converter. Also, this converter is bidirectional and can transfer energy both from input to output and from output to input.

The disadvantage of this type of converter is the need to use two separate chokes. This leads to a significant increase in its overall dimensions and reduces the scope of its application. Also, the converter has an increased amplitude of the pulsed current in the chokes, which leads to additional losses and reduces the overall efficiency of the converter.

The technical result consists in creating a bidirectional voltage converter with a reduced level of high-frequency oscillations at the input and output of the converter module due to the presence of a magnetic connection between the chokes, which also improves the electromagnetic compatibility of this device with consumers connected to it and its common supply network, reduces the size of the converter and leads to to a decrease in the maximum current amplitude in the chokes and transistors of the converter.

The technical result is achieved by the fact that a bidirectional voltage converter with coupled chokes consisting of two transistors, a control circuit, three capacitors and two chokes, characterized in that two chokes are galvanically and magnetically connected to each other and are located on the same core.

The essence of the invention is illustrated by drawings, where in Fig. 1a shows a diode rectified buck converter, FIG. 1b shows a synchronous rectifier buck converter, FIG. 2a shows a diode rectified boost converter, FIG. 2b shows a synchronous rectifier boost converter, FIG. 3 shows a diagram of a bidirectional voltage converter with coupled chokes, FIG. 4 shows an example of a buck-boost design of a bi-directional voltage converter with coupled chokes, FIG. 5 shows an example of a step-down design of a bidirectional voltage converter with coupled chokes.

In FIG. 1-5 the following designations are accepted:

1,7,11,12 - transistor;

2 - diode;

3,10,14,15 - throttle;

4,9,17 - buffer capacitor;

5 - core;

6.13 - control scheme.

8.16 - capacitor.

A bidirectional voltage converter with coupled chokes consists of two transistors, a control circuit, three capacitors and two chokes galvanically coupled and located on the same core. The proposed bidirectional converter with coupled chokes has the possibility of reverse switching.

The use of such a converter makes it possible to combine this converter both in a step-down converter and in a step-up converter. It is possible to perform the converter in the form of a serial connection of a step-up and step-down converter of this design, to obtain a step-down converter, and a reverse series connection of a step-down and step-up converter of this design, to obtain a step-down converter.

A bidirectional voltage converter with coupled chokes operates as follows.

When the supply voltage is connected to point V1 through a buffer capacitor 4, which serves as compensation for the communication line, and the load is connected to point V2. This converter works as a step-down voltage converter. When control signals are applied to close transistor 1 and open transistor 7 by control circuit 6, the current begins to flow through the circuit through inductor 3, open transistor 1 and through the load connected to V2. In addition, part of the current also flows through inductor 10, capacitor 8 and transistor 1, closes through the load connected to point V2, and is additionally filtered by buffer capacitor 9. Due to the introduced common magnetic coupling between inductors 3 and 10, we obtain a compensated total current, which is significant reduces voltage ripple at the input and output of the converter.

If you connect a power source to point V2 through a buffer capacitor 9, which serves as a compensation for the communication line, and a load to point V1, then this converter will become a step-up converter.

This device works as follows: when power is applied to point V2, this potential through the substrate diode of transistor 1 will connect to the potential of the input network and become equal to it minus the direct drop on the substrate diode. The voltage on the capacitor 8 will also be equal to the same potential. The control circuit 6 gives a signal and opens the transistor 7, the current begins to flow through the circuit V2-7-10 - a common wire, but since the inductance of the inductor 10 prevents a sharp increase in current, the voltage at the connection point of the inductor 10 and capacitor 8 increases to the voltage of point V2, which in turn raises the voltage at the connection point 1-8-3 to twice the level of the input voltage. The control circuit 6 closes the transistor 7, the current in the inductor 10 begins to decrease exponentially, due to this, the voltage at the connection point of the inductor 10 and the capacitor 8 begins to decrease in inverse proportion to the opening time of the transistor 7 relative to the supply voltage. In parallel, the current will also flow through the inductor 3 to the load connected to point V1. In this case, the output voltage at point V1 will be integrated by the filter obtained from inductor 3 and the load connected to V1. After the transistor 7 is closed, after a certain waiting time, the control circuit 6 opens the transistor 1, the potential at the junction point of the transistor 1 and the capacitor 8 will again equal the potential of the input voltage. And it is additionally filtered by a buffer capacitor 4. Further cycles of work are repeated cyclically with the corresponding transistors switched on and off in turn.

The main advantage of this design of a bidirectional converter with coupled chokes is a reduction in weight and size, and a common-mode noise filter formed using such winding of chokes more effectively suppresses interference and improves the EMC of the converter, compared to other types of similar devices. It also reduces the amplitude of the current in the chokes and power transistors, which leads to an increase in the efficiency of the converter.

Example 1

The buck-boost version of this module contains two series-connected links connected in raising and lowering inclusions (Fig. 4).

Buffer capacitor 4 is connected with one of its outputs to the common wire of the circuit, and with the other to inductor 3, to which point V1 is connected. Two chokes 3 and 10 are made on a common core 5, with a capacitor 8 located between them. Transistors 1 and 7 are connected to the connection points of the capacitor 8 and two chokes 3 and 10, respectively. A buffer capacitor 9 is connected to the connection point of transistors 1 and 7. Transistors 1 and 7 are controlled by control circuit 6. Transistors 11 and 12 are connected to the connection point of buffer capacitor 9 with transistors 1 and 7, the gates of which are supplied with control signals from control circuit 12. Transistors 11 and 12 are interconnected by a capacitor 16, and the outputs of the chokes 14 and 15 are connected to these outputs, respectively, which in turn are made on the same core 5. Transistors 11 and 12 are controlled by the control circuit 13. A buffer capacitor 17 is connected to the opposite output of the choke 15 , this connection forms a point V2.

The presented converter is completely symmetrical and can carry out bidirectional power transfer from point V1 to V2 or vice versa.

Example 2

The step-down version of this converter contains two serially connected links connected in step-down and step-up switching (Fig. 5).

Buffer capacitor 17 is connected with one of its terminals to the common wire of the circuit, and with the other to transistors 11 and 12, this connection forms a point V1. Two chokes 14 and 15 made on a common core 5, with a capacitor 16 located between them, are connected to a common wire and a buffer capacitor 4, respectively. Chokes 3 and 10, made on the same core 5, are connected to the connection point of the buffer capacitor 4 and choke 14 and the common wire. Capacitor 8 is connected between chokes 3 and 10. Transistor 1 is connected to the connection point of choke 3 and capacitor 8. capacitor 8 is connected to transistor 7. Transistors are connected to each other and capacitor 9 at point V2. The first pair of transistors 11, 12 are controlled by the control circuit 13, and the second pair 1 and 7 are controlled by the control circuit 6.

The presented converter is completely symmetrical and can carry out bidirectional power transfer from point V1 to V2 or vice versa.

Claims (1)

Bidirectional voltage converter with coupled chokes, consisting of two transistors, a control circuit, three capacitors and two chokes, characterized in that the two chokes are galvanically and magnetically connected to each other and are located on the same core.

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