RU2779907C1 - Three-phase rectifying device - Google Patents

Abstract

FIELD: electrical engineering.

SUBSTANCE: invention relates to electrical engineering, namely to three-phase rectifier devices (RD) with a transformerless input (TLI) based on pulse stabilized high-frequency converters. The effect is achieved by the fact that the rectifier device is built from three single-phase, each of which is made on power modules with "n+1" redundancy, while the module of the first single-phase rectifier is connected to phase A by one input, the second - to phase B, the third - to phase C, the other input all modules are connected to neutral. The invention can be used in power supply systems for mobile communication objects, where small-sized and reliable VUs with a power of several kW with a sinusoidal shape of the input current are required, operating from electrical units of comparable power with a three-phase voltage of 380 V.

EFFECT: ensuring the possibility of operation of the rectifier device from three-phase networks with a linear voltage of 380 V.

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Description

The invention relates to electrical engineering, namely to three-phase rectifier devices (VU) with a transformerless input (BTV) based on pulse stabilized high-frequency converters (converters).

The invention can be used in power supply systems for mobile communication objects, where small-sized and reliable VUs with a power of several kW with a sinusoidal input current are required, operating from electrical units of comparable power with a three-phase linear voltage of 380 V.

Three-phase rectifiers with BTV are known that meet most of the requirements, consisting of a diode bridge, a power factor corrector (PFC) and a converter [1].

Modern rectifier devices are mainly based on a bridge converter operating at a frequency of 100 kHz and higher with phase modulation [1, 2]. In the converter, switching of keys occurs at zero voltage. The gate of MIS transistors is signaled to unlock only when the drain-source voltage is zero. In such a converter, static and dynamic losses are minimized, which makes it possible to obtain a high efficiency of the order of 92 ... 94%. In addition, the high speed of MIS transistors allows them to operate at a high frequency, which reduces the size of powerful PFCs and converters. Currently, portable, high-performance VUs are designed exclusively on such transistors. But due to the complexity of circuit solutions and a large number of powerful discrete elements that cannot be integrated, their reliability turned out to be insufficient for use in modern communication equipment (AC).

An analysis of the WUs, which have the same structure and are made on the element base of approximately the same degree of integration, shows that as the power increases, the time between failures T _o decreases. At a power of 1 kW, the value of T _o does not exceed 50 thousand hours [2], while in a modern AS on microcircuits, the required value of T _o is hundreds of thousands of hours. In order to maintain the established percentage (20%) for power supply failures in the AU, the WU must have a value of T _about at least 500 thousand hours.

One of the promising ways to create a powerful VU that meets the requirements for the reliability of the AU is their modular construction. To obtain the necessary reliability, the VU, designed for power Р _n , is built from n parallel-connected main power modules (hereinafter referred to as modules) with power Р _n / n and are introduced into it to the reserve ones. Already with one additional module, the value of T _o increases by several orders of magnitude, so the WUs are built according to the “n + 1” principle [2, 3, 4].

A necessary condition for obtaining such high reliability is the complete, reliable control of each module and the replacement of the module with the three-phase rectifier turned on [2]. Also, to ensure parallel operation, it is necessary to embed a device in the module that provides uniform current distribution [3]. The signal for regulating the output current is supplied to the module via an additional input.

Known rectifier [4], taken as a prototype, built on modules with redundancy "n + 1", each module contains a diode bridge, CCM, built on the basis of a boost-type switching regulator [1, 4], and a converter made on MIS- transistors. But such a rectifier only works from three-phase networks with a voltage of 220 V.

Most hardware connections require VUs operating from a three-phase voltage of 380 V. At this voltage, the VU elements operate at the maximum input voltage

U _in.m \u003d 380 × k ₁ × k ₂ ,

where k ₁ - steady state deviation, k ₁ =1.15;

k ₂ - transient deviation, k ₂ =1.2.

Thus, the voltage at the input of the three-phase bridge

U _in.m \u003d 380 × 1.15 × 1.2 \u003d 524 V,

and the voltage at the output of the three-phase bridge

U _input.m \u003d U _input.m / k ₃ \u003d 524 / 0.74 \u003d 742 V,

where k ₃ - coefficient of linear EMF, k ₃ =0.74.

The voltage on the storage capacitor of the KKM also cannot be set below 742 V [1]. The same voltage is applied to the MIS transistors of the PFC and converters.

Taking into account the minimum voltage margin k ₄ \u003d 1.2, to ensure reliability, a transistor with an allowable voltage U _d \u003d k ₄ × U _in.m is needed, i.e.

U _d \u003d k ₄ × U _in.m \u003d 1.2 × 742 \u003d 890 V.

Currently, there are no MIS transistors with such a voltage.

In the future, perhaps, MIS transistors with a drain voltage of more than 900 V will be developed, but obviously with lower dynamic characteristics and a higher channel resistance than low-voltage ones.

Known three-phase PFCs according to the Vietta-rectifier scheme allow the use of transistors with half the voltage, however, such PFCs contain many switches and reactive elements, and therefore have large weight and size indicators. They are used in industry with a power of tens of kW and are not suitable for small-sized modular design with "n + 1" redundancy.

The aim of the invention is to ensure the possibility of operation of the rectifier device from three-phase networks with a linear voltage of 380 V.

This goal is achieved by the fact that the rectifier device is built from three single-phase, each of which is made on power modules with "n + 1" redundancy, while the module of the first single-phase rectifier is connected to phase A by one input, the second - to phase B, the third - to phase C, the other input all modules are connected to neutral.

Comparable analysis with the prototype shows that the proposed device will feature a new circuit solution. Thus, the claimed device meets the criterion of invention "novelty".

Comparison of the proposed device with the prototype shows that thanks to the new circuit solution, a new property of the proposed device appears, which consists in ensuring its operation from an input voltage of 380 V. This allows us to conclude that the proposed technical solution meets the criterion of "significant differences".

The figure shows a block diagram of a three-phase rectifier device, which includes:

1 - the first single-phase rectifier;

2 - second single-phase rectifier;

3 - the third single-phase rectifier;

4 - power modules;

5 - power module connectors.

As shown in the figure, a three-phase rectifier device contains three identical single-phase rectifiers, each of which consists of (n+1) power modules 4 connected in parallel.

In this case, the power modules 4 of the first single-phase rectifier 1 are connected with phase A by one input through the contact "a" of the connector of the power modules 5, the power modules 4 of the second single-phase rectifier 2 are connected with phase B by one input through the contact "a" of the connector of the power modules 5, the power modules 4 third 3 single-phase rectifiers are connected to phase C by one input through pin “a” of the connector of power modules 5, the second inputs of all power modules 4 of all single-phase rectifiers 1,2,3 are connected to neutral, the outputs of all power modules 4 through contacts “b” and "g" of the connector of power supply modules 5 is connected to the output of a three-phase rectifier, and additional outputs of the power modules designed to supply a signal for regulating the output current during parallel operation, which are abbreviated as "PAR" in the figure, are brought out through contact "e" and in each single-phase rectifier are interconnected.

Three-phase rectifier device works as follows.

A single-phase voltage is supplied to the input of each power supply module 4. PFC modules, made on the basis of step-up switching regulators, provide a sinusoidal form of the consumed current and voltage stabilization at the level of the mains voltage amplitude. The converter lowers this voltage to the required level of 28.5 V.

In operating mode, each single-phase rectifier gives power to the load R _n /3, and each module R _n /3 (p + 1).

If one of the modules in a single-phase rectifier fails, the output power is replenished by the remaining operable ones, while each module delivers power P _n /3p to the load. The replacement of the failed module is carried out with the rectifier running.

The technical result of the proposed technical device is the ability to operate the rectifier from three-phase networks with a linear voltage of 380 V.

Therefore, we can conclude that the goal set for this invention - enabling the operation of the rectifier device from three-phase networks with a linear voltage of 380 V - has been achieved.

The advantages of the proposed three-phase rectifier devices include the simplicity of its implementation, based on the use of widely known and used electronic elements and components.

The proposed three-phase rectifier device can be used in the creation of highly reliable DC power supply devices for various purposes.

The technical and economic effect due to the use of the proposed three-phase rectifier consists in a significant increase in the reliability of operation and an increase in the service life of direct current power supply devices built on its basis.

The quantitative value of the expected technical and economic effect from the use of the proposed three-phase rectifier device depends primarily on the scope of its application and specific embodiments - its determination is possible only after its practical implementation.

Sources of information

1. Korotkov S.M., Lukin A.V. Powerful AC-DC converters for uninterruptible power systems. /Power supply. No. 2, 2015, pp. 22-25.

2. Plotkin I.R., Nagaitsev A.N., Tverdoe I.V. Powerful modular rectifiers with percentage redundancy. /Components and technologies. No. 4, 2006, pp. 164-167.

3. Solid I.V. etc. Parallel connection of power modules. / Electronic components, No. 9, 2005, pp. 129-131.

4. HFE 1600 W1U-datasheet.

Claims (1)

A three-phase rectifying device built on power modules with redundancy (n + 1), with each power module containing a diode bridge, a power factor corrector and a high-frequency converter made on MIS transistors, characterized in that it consists of three identical single-phase rectifiers , each of which consists of (n + 1) power modules connected in parallel, while the power modules of the first single-phase rectifier are connected to phase A by one input through contact "a" of the power module connector, the power modules of the second single-phase rectifier are connected by one input through contact "a » of the power modules connector are connected to phase B, the power modules of the third single-phase rectifier are connected to phase C by one input through pin "a" of the power modules connector, the second inputs of all power modules of all single-phase rectifiers are connected to neutral, the outputs of all power modules through contacts "b" and "g" of the connector of the power modules are connected to the output of a three-phase rectifier, and additional the outputs of the power modules, designed to supply a signal for regulating the output current in parallel operation, are brought out through the “d” contact and are interconnected in each single-phase rectifier.

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