KR102316624B1 - Power converter - Google Patents

Abstract

A power conversion device is provided. The power conversion device includes a conversion unit for converting the DC electricity stored in the storage unit into AC electricity; a control unit for controlling the conversion unit; and a processing unit for monitoring or preventing malfunction of the conversion unit.

Description

A power converter capable of diagnosing switching element failures {POWER CONVERTER}

The present invention relates to a power conversion device for converting direct current electricity into alternating current electricity.

All loads require power to operate them.

In general, grid power having a related voltage and current is supplied for the operation of a load. In general, there is a case where an error occurs in the grid power supply and the power supply is cut off.

In this case, although it is restored after a predetermined period of time and the supply of system power is made again, the data that was working through the load is lost or, in particular, when life-related equipment such as a hospital is used as a load, the patient's life is lost. It is very dangerous to cut off the supply of the grid power even temporarily because it is directly connected to the

Accordingly, in recent years, a means for detecting an abnormality in the grid power and supplying power instead of the grid power to the load when an error occurs has been developed and is being operated together with the grid power line. function to supply

Recently, as eco-friendly energy can be utilized, power of an energy storage system (ESS) is used instead of a battery, or a battery and an energy storage system (ESS) are used sequentially.

In applying a battery or energy storage system (ESS), the power at the time of storage may be direct current (DC) or alternating current (AC). If the power between the supply means and the load is the same, there is no problem, but in other cases, a means for properly converting into direct current (DC) or alternating current (AC) is required. This is commonly referred to as a power converter system (PCS), and the capacity of the power converter system (PCS) varies according to the amount of power required by the load.

In the case of DC/DC converters or DC/AC inverters constituting the power conversion device (PCS), the number of DC/DC converters or DC/AC inverters varies depending on the required capacity, so the specifications and sizes vary, and they are usually integrally formed.

As described above, when each of a plurality of DC/DC converters or DC/AC inverters is configured as a single aggregate, if one of the aggregates fails or requires maintenance, the rest of the aggregates are also replaced and There is a problem in that the power supply is interrupted as a result because it must be repaired, and the operation of other components that are not broken in this process must be stopped.

Korean Patent Publication No. 1774169 discloses a power management system using a modularized power conversion device.

Korean Patent Publication No. 1774169

An object of the present invention is to provide a power conversion device for dealing with a malfunction of a conversion means for converting direct current electricity into alternating current electricity.

The power conversion device of the present invention includes a conversion unit for converting DC electricity stored in the storage unit into AC electricity; a control unit for controlling the conversion unit; and a processing unit for monitoring or preventing malfunction of the conversion unit.

The power conversion device of the present invention may include a processing unit for monitoring or preventing malfunction of a converter that converts direct current (DC power) into alternating current (AC power).

When a malfunction of the converter occurs, a load receiving the AC electricity output from the converter may be damaged.

The processing unit of the present invention monitors a malfunction of the converter, and when a malfunction of the converter is detected, it is possible to prevent the malfunction.

According to the present invention, it is possible to monitor each of a plurality of transistors constituting the conversion unit. Therefore, according to the present invention, an individual transistor in which a malfunction has occurred and a normal transistor can be distinguished.

A specific individual transistor in which a malfunction has occurred is recognized by a user performing maintenance, and only the corresponding individual switch can be replaced by the user.

In order to prevent fire or load damage due to excessive current, the power conversion device of the present invention may forcibly stop the operation of a specific transistor in which a malfunction is detected.

In order to prevent the quality of the AC electricity output from the converter from being deteriorated due to the stop of a specific transistor, the prevention part may be used. According to the prevention unit of the present invention, a redundancy member having the same characteristics as the malfunctioning specific transistor can perform the function of the specific transistor instead. While the redundancy member performs the function of a specific transistor instead, the user can normally perform maintenance work on the malfunctioning specific transistor. In addition, the quality of AC electricity output from the converter may also be maintained without deterioration.

In particular, the monitoring unit and the prevention unit of the present invention are very useful when a heterogeneous battery system in which a lead-acid battery and a lithium iron dioxide battery are connected in series and parallel as an input source. Electrical stress may be accumulated in the converter or the like due to a difference in characteristics between different types of batteries. In particular, a serious stress may be accumulated in a transistor such as an insulated gate bipolar transistor (IGBT) that performs a high-speed switching operation of converting DC electricity into alternating current by phasing it. As a result, various types of damage to the transistor may occur, and the damage to the transistor may seriously damage a load receiving AC electricity from the power conversion device as well as damage to the PCS represented by the power conversion device. According to the present invention, a specific transistor malfunctioning among a plurality of transistors is accurately specified and displayed by the monitoring unit, and countermeasures for preventing/reducing malfunction, such as redundancy, can be applied to the specific transistor. Therefore, the reliable operation of the converter is maintained and the effect of very easy maintenance can be generated.

According to the power conversion device of the present invention, it may be possible to diagnose a failure of a switching element such as a transistor.

1 is a schematic diagram showing a power conversion device of the present invention.
2 is a schematic diagram showing another power conversion device of the present invention.
3 is a schematic diagram showing a part of another power conversion device of the present invention.

Hereinafter, with reference to the accompanying drawings, embodiments of the present invention will be described in detail so that those of ordinary skill in the art to which the present invention pertains can easily implement them. However, the present invention may be embodied in many different forms and is not limited to the embodiments described herein. And in order to clearly explain the present invention in the drawings, parts irrelevant to the description are omitted, and similar reference numerals are attached to similar parts throughout the specification.

In the present specification, duplicate descriptions of the same components will be omitted.

Also, in this specification, when it is mentioned that a certain element is 'connected' or 'connected' to another element, it may be directly connected or connected to the other element, but another element in the middle. It should be understood that there may be On the other hand, in this specification, when it is mentioned that a certain element is 'directly connected' or 'directly connected' to another element, it should be understood that the other element does not exist in the middle.

In addition, the terms used herein are used only to describe specific embodiments, and are not intended to limit the present invention.

Also, in this specification, the singular expression may include the plural expression unless the context clearly dictates otherwise.

Also in this specification, terms such as 'include' or 'have' are only intended to designate that the features, numbers, steps, operations, components, parts, or combinations thereof described in the specification exist, and one or more It should be understood that the existence or addition of other features, numbers, steps, operations, components, parts or combinations thereof is not precluded in advance.

Also in this specification, the term 'and/or' includes a combination of a plurality of listed items or any of a plurality of listed items. In this specification, 'A or B' may include 'A', 'B', or 'both A and B'.

Also, in this specification, detailed descriptions of well-known functions and configurations that may obscure the gist of the present invention will be omitted.

1 is a schematic diagram showing a power conversion device 100 of the present invention.

The power conversion apparatus 100 illustrated in FIG. 1 may include a conversion unit 110 , a control unit 130 , and a processing unit 200 . The power conversion device 100 of FIG. 1 may include a power conditioning system (PCS) that converts DC electricity stored in a battery into AC electricity required by the load 90 .

The conversion unit 110 may convert the DC electricity stored in the storage unit 10 into AC electricity.

For example, the converter 110 may be provided with a plurality of transistors for turning on/off direct current electricity at different times. Since the on-off timings are different from each other, electricity output from each transistor may be a pulse signal having different phases. When a pulse signal is input to a smoothing circuit such as a capacitor provided in the converter 110, three-phase AC electricity may be completed and output.

The controller 130 may control the converter 110 . For example, the controller 130 may provide a control signal to a control terminal such as a gate terminal or a base terminal of a transistor provided in the converter 110 . For example, the controller 130 may be provided with a driver that provides a control signal to the control terminal of the transistor.

When an ON signal is input to the control terminal by the driver of the controller 130 , the source-drain or collector-emitter of the transistor conducts and electricity may flow through the transistor.

When the OFF signal is input to the control terminal by the controller 130 , the electrical connection between the source-drain or the collector-emitter of the transistor may be cut off, and electricity may not flow through the transistor.

If the transistor is turned on and off periodically using a control signal, direct current electricity can be transformed into a pulse form. In this case, if a phase difference is applied to the control signal of the same period and provided to each of the plurality of transistors, electricity output from the plurality of transistors may take the form of an alternating current. When it passes through the smoothing circuit additionally provided at the output terminal of the transistor, actual AC electricity is formed, and the AC electricity may be provided to various loads 90 .

In the process of converting the DC electricity stored in the storage unit 10 into AC electricity, the transistor of the converting unit 110 may naturally deteriorate. If the characteristics of the direct current electricity provided from the storage unit 10 change every time, the deterioration of the converter 110 may be accelerated. If the converter 110 malfunctions due to deterioration, various loads 90 operating using AC electricity may not operate normally. The processing unit 200 may be used to monitor or prevent malfunction of the conversion unit 110 .

For example, different types of first and second batteries 11 and 12 may be provided in the storage unit 10 . Both the first battery 11 and the second battery 12 may store direct current electricity. In this case, the first DC electricity d1 output from the first battery 11 and the second DC electricity d2 output from the second battery 12 may have different characteristics. For example, even if a post-processing means for rating voltage and current is provided, a small voltage difference or current difference may occur between the first DC electricity and the second DC electricity. When a state in which direct current electricity having different characteristics is alternately input and input together is repeated, deterioration of the converter 110 may be accelerated.

The converter 110 outputs AC electricity a of a first characteristic even when the first DC electricity d1 is input from the first battery 11 , and even when the second DC electricity d2 is input from the second battery 12 , the first characteristic of alternating current a can be output. In this process, the lifetime of the transistor may be shortened due to the stress accumulated in the transistor of the converter 110 .

At least one of the monitoring unit 210 and the prevention unit 230 may be provided in the processing unit 200 to prepare for a malfunction of the transistor with a shortened lifespan.

The monitoring unit 210 may monitor a malfunction of the converter 110 generated in the process of converting the first DC electricity d1 and the second DC electricity d2 having different characteristics into AC electricity a having the same first characteristic.

The prevention unit 230 may prevent malfunction of the converter 110 generated in the process of converting the first DC electricity d1 and the second DC electricity d2 having different characteristics into AC electricity a having the same first characteristic. The first characteristic may include amplitude, frequency, phase difference, noise, and the like of AC electricity.

2 is a schematic diagram showing another power conversion device 100 of the present invention. 2 may be a schematic diagram of a circuit diagram of the power conversion device 100 .

A plurality of transistors T1 , T2 , T3 , T4 , T5 , and T6 forming a PWM rectifier (Pulse Width Modulation rectifier) for converting DC electricity into AC electricity may be provided in the converter 110 . The transistor is preferably an IGBT (Insulated Gate Bipolar Transistor) formed for power for a power source.

The processing unit 200 may be provided with a monitoring unit 210 that compares the voltage across the transistor with a reference voltage. In the case of an IGBT, the voltage across both ends may represent a voltage between source and drain. The reference voltage may be set by the controller 130 . The reference voltage may be set to detect a point where more current flows between the source and the drain than usual when the transistor malfunctions and the voltage is different from usual. The monitoring unit 210 may generate a fault signal F when the voltages at both ends satisfy the reference voltage.

Light emitting devices 219 R1, R2, R3, R4, R5, and R6 that emit light according to the fault signal F may be provided for each transistor. For example, the first light emitting device R1 may be provided to match the first transistor T1. A second light emitting device R2 may be provided to match the second transistor T2. A third light emitting device R3 may be provided to match the third transistor T3. A fourth light emitting device R4 may be provided to match the fourth transistor T4. A fifth light emitting device R5 may be provided to match the fifth transistor T5. A sixth light emitting device R6 may be provided to match the sixth transistor T6.

When the fault signal F is generated by the specific monitoring unit 210 that monitors the specific transistor, the specific light emitting device 219 indicating the specific transistor among the plurality of light emitting devices 219 may emit light. For example, the fault signal F may be generated by the monitoring unit 210 that checks the voltage across the first transistor T1. The corresponding fault signal may be provided only to the first light emitting device R1 allocated to match the first transistor T1. Only the first light emitting element R1 receiving the fault signal F among the plurality of light emitting elements 219 may emit light. Through light emission of the first light emitting device R1, the user can very easily recognize that the first transistor T1 is in a malfunctioning state. A user who has confirmed the malfunction of the first transistor T1 may repair or replace the first transistor T1 with a new one.

Even if the light emitting device 219 emits light, if the user does not check the light emitting device 219 , a malfunctioning state of the transistor may continue. The prevention unit 230 may be used to prevent various problems occurring due to the continuous state of the malfunction.

The monitoring unit 210 and the driver may be separately provided for each transistor.

When the fault signal F is generated by the specific monitoring unit 210 that monitors a specific transistor, the prevention unit 230 may stop the operation of a specific driver that provides a control signal to the specific transistor.

When the operation of the specific driver is stopped by the prevention unit 230 , the operation of the specific transistor operated by the control signal of the corresponding driver may also be stopped. Stopping the operation may be more beneficial than a malfunction, but a power outage may occur or AC electricity with reduced quality may be output from the converter 110 . Therefore, it is preferable to provide a method for excluding the malfunctioning transistor from the converter 110 , and preventing a power outage and reducing the quality of AC electricity.

3 is a schematic diagram showing a part of another power conversion device 100 of the present invention.

When the fault signal F is generated by the specific monitoring unit 210 that monitors the specific transistor, the prevention unit 230 may change the path of the control signal provided from the specific driver to the specific transistor.

The redundancy member S S formed to be the same as the specific transistor may be provided according to the number of transistors. For example, the redundancy member S S may include the same transistor as a specific transistor. Each redundancy member S may be connected in parallel to each transistor.

A path member 239 disposed between the control terminal of the redundancy member S and the control terminal of the transistor may be provided. The path member 239 may include a switch.

The path member 239 may maintain a switched state to normally supply the control signal of the driver to the control terminal of the transistor. Therefore, normally, the control signal may be provided only to the transistor of the conversion unit 110 among the redundant member S and the transistors of the conversion unit 110 . Accordingly, the redundancy member S is not normally operated and only the transistor of the converter 110 may be normally operated.

When the fault signal F is generated, the prevention unit 230 may switch the path member 239 such that the control signal input from the driver to the control terminal of the transistor is blocked. Also, when the fault signal F is generated, the prevention unit 230 may switch the path member 239 such that the control signal is input to the control terminal of the redundancy member S instead of the control terminal of the transistor.

Accordingly, according to the prevention unit 230 and the path member 239 , the transistor of the conversion unit 110 in which the malfunction has occurred may stop operating, and the redundancy member S may operate to perform the role of the transistor instead. As a result, since the normal transistor continuously exists from the standpoint of the conversion unit 110 as a whole, blackout can be prevented and deterioration of AC electricity quality can be prevented. In addition, the malfunctioning transistor may be recognized by the user by the light emitting device 219 or the like, and may be replaced or repaired. When the maintenance of the malfunctioning transistor is completed, the path member 239 may be returned to an original state by the user. In other words, the path member 239 may return to a state connected to the control terminal of the transistor by a manual operation by a user.

After the path member 239 is returned, DC electricity is converted into AC electricity by the maintenance-completed transistor, and the transistor may be monitored again by the monitoring unit 210 .

Although the embodiment of the present invention has been described in detail above, the scope of the present invention is not limited thereto, and various modifications and improvements by those skilled in the art using the basic concept of the present invention as defined in the following claims are also presented. It belongs to the scope of the invention.

10...Storage 11...First battery
12...second battery 90...load
100...Power converter 110...Converter
130...control unit 200...processing unit
210...monitoring unit 219...light emitting element
230...blocking part 239...path missing

Claims (5)

a conversion unit for converting the direct current electricity stored in the storage unit into alternating current electricity;
a control unit for controlling the conversion unit;
and a processing unit that monitors or prevents malfunction of the conversion unit.
A plurality of transistors forming a PWM rectifier (Pulse Width Modulation rectifier) for converting the DC electricity into the AC electricity is provided in the converter,
A driver for providing a control signal to the control terminal of the transistor is provided in the control unit,
The processing unit is provided with a monitoring unit for comparing the voltage across the transistor with a reference voltage,
The monitoring unit generates a fault signal when the voltage at both ends meets the reference voltage,
The monitoring unit and the driver are provided for each transistor,
In the processing unit, when the fault signal is generated by a specific monitoring unit that monitors a specific transistor, a prevention unit is provided for stopping only the operation of a specific driver that provides the control signal to the specific transistor among a plurality of drivers,
Due to the stop of the operation of the specific driver, only the operation of the specific transistor that was operated by the control signal of the specific driver among the plurality of transistors is stopped.
According to claim 1,
A first battery and a second battery of different types are provided in the storage unit,
The converter outputs AC electricity of a first characteristic even when first DC electricity is input from the first battery, and outputs AC electricity of the first characteristic even when second DC electricity is input from the second battery,
The monitoring unit monitors a malfunction of the conversion unit generated in the process of converting the first DC electricity and the second DC electricity having different characteristics into AC electricity having the same characteristics,
The prevention unit is a power conversion device to prevent the malfunction.
According to claim 1,
A light emitting element emitting light according to the fault signal is provided for each transistor,
When the fault signal is generated by a specific monitoring unit that monitors a specific transistor, a specific light emitting device instructing the specific transistor among a plurality of light emitting devices emits light.
delete According to claim 1,
A redundancy member formed in the same manner as the specific transistor is provided according to the number of the transistors,
Each redundancy member is connected in parallel to each transistor,
a path member disposed between the control end of the redundancy member and the control end of the transistor is provided;
The path member normally maintains a switched state to supply the control signal of the driver to the control terminal of the transistor,
When the fault signal is generated, the prevention unit blocks the control signal input from the specific driver to the control terminal of the specific transistor, and the control signal is connected in parallel to the specific transistor instead of the control terminal of the specific transistor. switching a specific path member to be input to the control end of the redundancy member;
The specific path member is returned to a state connected to the control terminal of the transistor by a manual operation by a user.

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