KR102079527B1 - Apparatus for controlling inverter - Google Patents

Abstract

An inverter control device is disclosed. The apparatus of the present invention includes a storage unit for storing parameters for a command loss determination operation of the inverter, and a control unit for determining a command loss of the inverter and providing an operation command and a frequency command to the PWM controller to continuously operate the inverter based on the parameter. It includes.

Description

Inverter Controller {APPARATUS FOR CONTROLLING INVERTER}

The present invention relates to an inverter control device.

In general, an inverter is an inverting device that converts direct current (DC) into alternating current (AC). Inverters used in the industrial industry receive electric power supplied from a commercial power source and supply voltage to an electric motor by varying its voltage and frequency. It is defined as a series of devices that control the use of speed with high efficiency.

In order to input the voltage and frequency supplied to the motor to the inverter, the analog input is conventionally received by using a device attached to the outside of the inverter, such as a human machine interface (HMI), but in recent years, the system has been enlarged. In addition, in order to control one-to-many, the case where the operation command and the frequency command are provided to an inverter via communication is increasing. For example, motors in large systems such as heating, ventilating, and air conditioning (HVAC) systems that control flow and hydraulic pressure, such as fans and pumps, are controlled by the upper control unit with an inverter. And the reference frequency.

In such a system, even when a problem occurs in the communication system, it may be necessary to continuously operate the system. However, when the system encounters a situation in which communication is impossible, there is a problem that the continuous operation is impossible according to the conventional system. There is a problem in that it is impossible to cope with and affect the operation of the entire inverter system.

The technical problem to be solved by the present invention, without equipment additionally configured in the inverter, to provide an inverter control device that enables continuous operation when a command received by communication is lost.

In order to solve the above technical problem, in the inverter system including an inverter unit comprising a plurality of switching elements, and a PWM control unit for providing a gate voltage generated by a pulse width modulation (PWM) waveform to the plurality of switching elements; In one embodiment of the present invention for controlling the inverter, the storage unit for storing a parameter for the command loss determination operation of the inverter; And a controller configured to determine a command loss of the inverter and to provide an operation command and a frequency command to the PWM controller to continuously operate the inverter by the parameter.

In one embodiment of the present invention, the parameter may include a command loss operation setting, a command loss determination time, a command loss determination delay time and a command loss input setting.

In one embodiment of the present invention, when the command loss input setting parameter is a communication, the control unit loses a command if the time for which data is not received from a higher control device is maintained for a time corresponding to the command loss determination time parameter. It can be judged as

In one embodiment of the present invention, when the command loss input setting parameter is an analog input, the controller is further configured to provide a command if the time when the analog input of the inverter is out of the normal range is maintained for a time corresponding to the command loss determination time parameter. You can judge the loss.

In one embodiment of the present invention, the control unit may determine that the command loss after the command loss determination delay time elapses.

In an embodiment of the present disclosure, the parameter stored in the storage unit may further include a command loss determination frequency, and the control unit may determine that the command loss occurs when the output frequency of the inverter is greater than the command loss determination frequency. .

In one embodiment of the present invention, the command-initiated operation setting parameter is a first operation mode for holding an input of the command-inverted inverter, a second operation mode for holding an output of the inverter in a command-induced loss, and a command loss. The inverter may be any one of the third operation modes in which the inverter operates according to a time set frequency.

In one embodiment of the present invention, when the command on-run operation setting parameter is the first operation mode, the control unit operates the command and the frequency command to maintain the operating frequency of the inverter at the command frequency of the inverter on the command-on basis. May be transmitted to the PWM control unit.

In an embodiment of the present disclosure, when the command loss is released, the control unit may transmit the operation command and the updated command frequency to the PWM control unit when the command frequency is updated.

In one embodiment of the present invention, when the command on-run operation setting parameter is the second operation mode, the control unit may operate the command and the frequency command to maintain the operating frequency of the inverter at the output frequency of the inverter on the command-on basis. May be transmitted to the PWM control unit.

In one embodiment of the present invention, when the command loss is released, the control unit may transmit the operation command and the command frequency to the PWM control unit to operate at the command frequency when the command loss is released.

In an embodiment of the present disclosure, when the command execution mode operation setting parameter is a third operation mode, the controller may transmit an operation command and a frequency command to the PWM control unit so that the inverter operates at the set frequency.

In one embodiment of the present invention, when the command loss is released, the control unit may transmit the operation command and the command frequency to the PWM control unit to operate at the command frequency when the command loss is released.

In one embodiment of the present invention, when the command execution mode operation setting parameter is the fourth operation mode, the controller may leave the inverter.

In one embodiment of the present invention, when the command on-run operation setting parameter is the fifth operation mode, the control unit may transmit a driving command to the PWM control unit to generate a trip and cause the inverter to stop.

In one embodiment of the present invention, when the command on-run operation setting parameter is the fourth operation mode, the control unit may transmit a driving command and a frequency command to the PWM control unit so that the inverter operates at the deceleration frequency.

In the present invention as described above, since the inverter itself can be operated continuously in the case of command loss without additional equipment, the user does not need the installation space of additional equipment and additional equipment, so the total cost of ownership in terms of the entire system It has the effect of reducing the installation cost by reducing the TCO.

In addition, the present invention has the effect of providing the stability of the system because it is possible to prevent the accident of the inverter system by the continuous operation in the case of command loss.

1 is a configuration diagram of an inverter system to which the present invention is applied.
2 is a block diagram of an inverter control apparatus according to an embodiment of the present invention.
3 is a flowchart illustrating an inverter control method according to an embodiment of the present invention.

DETAILED DESCRIPTION In order to fully understand the constitution and effects of the present invention, preferred embodiments of the present invention will be described with reference to the accompanying drawings. However, the present invention is not limited to the embodiments disclosed below, but may be embodied in various forms and various changes may be made. However, the description of the embodiments is provided to make the disclosure of the present invention complete, and to fully inform the scope of the invention to those skilled in the art. In the accompanying drawings, for convenience of description, the size of the components is shown to be larger than the actual size, and the ratio of each component may be exaggerated or reduced.

Terms such as 'first' and 'second' may be used to describe various components, but the components should not be limited by the above terms. The term may be used only to distinguish one component from another. For example, a 'first component' may be referred to as a 'second component' without departing from the scope of the present invention, and similarly, the 'second component' may also be referred to as 'first component'. Can be. In addition, singular forms also include plural forms unless the context clearly indicates otherwise. Unless otherwise defined, terms used in the embodiments of the present invention may be interpreted as meanings commonly known to those skilled in the art.

Hereinafter, an inverter control apparatus according to an embodiment of the present invention will be described in detail with reference to FIGS. 1 to 3.

1 is a configuration diagram of an inverter system to which the present invention is applied.

As shown in the figure, the inverter system to which the present invention is applied is composed of an inverter 1 that receives power from an AC power supply 2 and provides a soaking voltage and frequency to the electric motor 3, and the inverter 1. The converter unit 31, the initial charge resistor 32, the initial charge switch 33, the DC link capacitor 34, the regenerative braking unit 36, the inverter unit 37, the current detection unit 38, the main control unit ( 10) and a pulse width modulation (PWM) control unit 20.

The converter unit 31 converts AC power into direct current, and a diode is usually used, and may be configured by combining a silicon controlled rectifier (SCR) and a diode in combination with the initial charge switch 33.

The initial charge resistance 32 and the initial charge switch 33 are to prevent the inrush current from being applied to the DC link capacitor 34 when the power is turned on, and the initial charge switch 33 is turned off when the power is turned on to make the initial charge. The inrush current is suppressed by the resistor 32, and after the inrush current is suppressed, the initial charge switch 33 may be turned on to separate the initial charge resistor 32 from the circuit. The initial charge switch 33 may be, for example, a magnetic contactor (MC). Meanwhile, as described above, the initial charge switch 33 may be configured in the form of an SCR in combination with the diode of the upper leg of the converter unit 31.

The DC link capacitor 34 smoothes the DC voltage rectified by the converter unit 31, and the inverter unit 37 may convert the DC voltage charged in the DC link capacitor 34 into an AC voltage. The inverter unit 37 is composed of a plurality of control switching elements, and the control switching element is, for example, a transistor, a metal oxide semiconductor field-effect transistor (MOSFET), an insulated gate bipolar transistor ( an insulated gate bipolar transistor (IGBT) or a gate turn-off thyristor (GTO). The inverter unit 37 may output an AC voltage having a magnitude and a frequency modulated by the PWM of the variable frequency.

The regenerative braking unit 36 may consume the regenerative energy as a resistor DB R when the DC voltage increased due to the regenerative operation or the like is larger than the set voltage.

The current detector 38 may detect a current flowing in each of the U, V, and W phases and provide the current to the main controller 10. In addition, the temperature detector 39 may detect the temperature of the switching element of the inverter unit 37 and provide the temperature to the main controller 10.

The main controller 10 may collect various types of information such as a DC voltage and a phase current of the inverter 1 and command various operations. The PWM control unit 20 generates a PWM waveform by using the operation command and the frequency command input from the main control unit 10 and uses the same to switch the switching elements and the regenerative braking unit 36 of each phase of the inverter unit 37. A gate voltage can be applied.

In the inverter system configured as described above, the main controller 10 receives a communication command including an operation command and a frequency command from an external upper controller (not shown) and provides it to the PWM controller 20. To this end, the main controller 10 may be provided with a communication module (not shown).

In such a configuration, when a communication system does not receive a communication command due to a failure of the communication system, according to the conventional inverter control, a multi-function input (2nd source) is operated by using a command loss to perform analog operation by manual operation. Driven in the manner. However, in such a case, wiring is required, and since a terminal block for additional input / output must be configured, there is a problem in that a separate hardware is required, and since the inverter is usually stopped, there is a problem that adversely affects the entire system.

Accordingly, the inverter control method of the embodiment of the present invention is to protect the inverter system by enabling continuous operation by setting even when a failure occurs in the communication system and a communication command is not received.

According to one embodiment of the present invention, the user does not need to add a separate power equipment, so that the total cost of ownership (TCO) of the system can be reduced by reducing the installation cost, and prevent the accident of the system in advance. Can be.

Inverter control method according to an embodiment of the present invention, if a communication command is not received, detects the command loss by detecting it, and controls the inverter to operate according to a preset command during emergency operation, if the communication returns to the normal state again Can be controlled to drive.

2 is a block diagram of an inverter control apparatus according to an embodiment of the present invention.

As shown in the figure, the inverter control apparatus of an embodiment of the present invention, which is provided to the main control unit 10 of the inverter 1, the communication unit 11, the user input unit 12, the control unit 13 and storage It may include a portion (14). However, it will be apparent to those skilled in the art that the main controller 10 may include other components in addition to the components described in the drawings.

The communication unit 11 may receive an operation command and a frequency command received according to a predetermined protocol through a wireless or wired network from a higher control device (not shown) and provide the same to the control unit 13. The manner in which the communication unit 11 communicates may vary, but may be, for example, a wired network such as RS-232.

In a system composed of a plurality of inverters 1, each inverter 1 may operate as a slave, and when receiving a command of a higher control device through the communication unit 11, transmits a response within a predetermined time. At this time, under the control of the controller 13, the communication unit 11 may transmit a response message to the upper control apparatus through the network.

The control unit 13 may drive the electric motor 2 by using the operation command and the frequency command received from the host controller through the communication unit 11. If the transmission / reception status of the communication is normal according to the speed, the operation frequency can be changed by the proportional integral derivative control according to the pressure.

When the user inputs various data set by the user for the inverter operation, the user input unit 12 may provide it to the controller 13. The user input unit 12 may be, for example, an HMI provided to allow a user to input data to the outside of the inverter 1. However, as an example, various input devices may be provided to the inverter 1. Alternatively, the user may transmit data to the main controller 10 of the inverter 1 through the network. In this case, the communication unit 11 may receive data corresponding to the setting parameter, and the control unit 13 may store the data in the storage unit 14.

The user may input setting parameters for continuous operation of the command phase for one embodiment of the present invention through the user input unit 12. The setting parameters for the command loss execution continuous operation may include a command loss operation setting, a command loss determination time, a command loss determination condition, and a command loss input setting as shown in the following table.

'Operation setting of command operation' is whether to operate under the control of the main controller 10 when the command signal is lost according to an embodiment of the present invention (ON), or whether to operate in the analog method according to the conventional method (OFF Will be set. If it is set to drive under the control of the main controller 10, the operation mode can be set as shown in the following table.

Operation mode Operation mode name Last move 0 NONE NONE One FREE-RUN TRIP 2 DEC TRIP 3 HOLD INPUT WARNING 4 HOLD OUTPUT WARNING 5 LOSS PRESET WARNING

If the operation mode is 0, no operation is performed when the command is lost. That is, if it is determined that the command is lost, the control unit 13 does not perform any operation.

The operation mode 1 is a free run operation, in which a trip is generated when the command loss is determined, and the inverter 1 is stopped.

In case of command loss, operation mode 2 decelerates and stops (trips) according to the set deceleration frequency. Normally, in the case of an operation command, the terminal information is input. In the operation mode 2, the control unit 13 can clear the contact information of the terminal block to 0. After the situation of command loss is cleared, the operation command is changed from the stop command to the operation command. Operation can be resumed when the change is made.

Operation mode 3 is a hold input, in which the operation frequency is maintained at the filtered command frequency for an arbitrary time interval, and the acceleration / deceleration to the command frequency is maintained when acceleration / deceleration is in progress. In this operation mode, when the command loss is canceled and the command frequency is updated again, operation can be performed at the updated command frequency. At this time, the reason for filtering during a random time interval is to remove the chattering (chattering) occurs when changing to the command frequency. That is, when the command frequency is input to a predetermined value it can be maintained the operating frequency at the command frequency.

Operation mode 4 is a hold output, in which the operating frequency is maintained at the filtered output frequency for an arbitrary time interval. In this operation mode, when the command loss is released, the drive can operate at the current command frequency.

Operation mode 5 is a loss preset, in which operation is performed at a frequency set on command. In other words, the frequency at which the driving is performed on the command is set in advance. In this operation mode, when the command loss is released, the drive can operate at the current command frequency.

Referring to the setting parameters for continuous operation for command loss, the command loss determination time defines the time for which the communication unit 11 does not receive data, and in this case, the command loss determination delay time has elapsed. The control unit 13 can then determine that the command is lost. Accordingly, the user may further input the 'command loss determination delay time' through the user input unit 12.

The command loss determination condition is that the command loss can be determined when the output frequency of the inverter 1 is equal to or higher than a predetermined output frequency, and the command loss determination frequency and the set frequency in the command loss operation mode 5 are determined. 'And' deceleration frequency 'in the operation mode 2.

In addition, 'command loss input setting', whether to determine the command loss through the analog input (for example, current, voltage, etc.), or whether the command loss if the communication unit 11 does not receive data? Can be determined. Normally, communication command loss refers to the case where data cannot be received from the upper level control device through communication, or the analog input (current, voltage, etc.) is out of the normal range. Therefore, the user can select whether to determine a command loss through communication or a command loss through an analog input.

As such, the parameter set by the user through the user input unit 12 may be stored in the storage unit 14. In addition, when the user sets the parameter through the user input unit 12, the display unit 15 may be further included to check the parameter input by the user. The user may check and set the above-described setting parameters and operation modes on the setting screen provided through the display unit 15.

The controller 13 may control the inverter 1 according to a parameter set by a user even when a command is lost according to an embodiment of the present invention. This will be described with reference to the drawings.

3 is a flowchart illustrating an inverter control method according to an embodiment of the present invention.

As shown in the drawing, the control unit 13 according to an embodiment of the present invention checks according to the set parameter whether the command loss condition is satisfied (S32) during the normal operation of the inverter 1 (S31), and checks a predetermined condition. If satisfied, it may be determined that the command is lost (S33). However, if the 'operation setting when setting the command' parameter is set to 'OFF', the related operation may not be performed even when the command is executed.

If the 'command loss input setting' parameter is communication, the command loss can be determined when the communication unit 11 does not receive data from the upper level control device for a predetermined time (time corresponding to the command loss determination time). have. Normally, the communication unit 11 receives data from the host controller at regular intervals. If the time of not receiving the data lasts for a predetermined time and the 'command loss determination delay time' elapses thereafter, the control unit 13 returns to the command loss. You can judge.

In this case, when determining the command loss, the controller 13 may determine whether the current output frequency of the inverter 1 is greater than the command loss determination frequency among the parameters set in the storage unit 14. If the current output frequency is smaller than the command loss determination frequency, it is regarded as not normal operation, and thus the command loss determination procedure may not be performed.

Alternatively, when the 'command loss input setting' parameter is an analog input, the controller 13 checks an analog input such as an input voltage and an input current of the inverter 1, and the time when the analog input is out of the normal range is a predetermined time (' Time corresponding to the command loss determination time '), the command loss can be determined. Even in this case, if the analog input is out of the normal range for a certain time, and after the command loss determination delay time has elapsed, the control unit 13 may determine that the command is lost.

In this case, when determining the command loss, the controller 13 may determine whether the current output frequency of the inverter 1 is greater than the command loss determination frequency among the parameters set in the storage unit 14. If the current output frequency is smaller than the command loss determination frequency, it is regarded as not normal operation, and thus the command loss determination procedure may not be performed.

When the control unit 13 determines the loss of the command, the control unit 13 may control the inverter 1 according to the operation mode of the set 'operation on command operation setting' parameter.

When the set operation mode is 0, the controller 13 may leave the inverter 1 without performing any operation even if it is determined that the command is lost.

When the set operation mode is 1, when the control unit 13 determines that the command is lost, the control unit 13 may transmit a driving command to the PWM control unit 20 to generate a trip and cause the inverter 1 to stop.

When the set operation mode is 2, the control unit 13 transmits an operation command and a frequency command to decelerate the inverter 1 according to the set deceleration frequency to the PWM control unit 20, and the inverter 1 decelerates according to the deceleration frequency. Can stop. To this end, the controller 13 may clear the contact information of the terminal block (not shown) of the inverter 1 to zero.

When the set operation mode is 3, the control unit 13 can maintain the input of the command phase. That is, the control unit 13 transmits the operation command and the frequency command to the PWM control unit 20 to maintain the operation frequency of the inverter 1 at the filtered command frequency for an arbitrary time period, and the inverter 1 at the command frequency. If the operating frequency is maintained or if it was during acceleration and deceleration, the acceleration and deceleration may be maintained at the command frequency.

When the set operation mode is 4, the control unit 13 can maintain the output of the command phase execution. That is, the control unit 13 transmits an operation command and a frequency command to the PWM control unit 20 to maintain the operation frequency of the inverter 1 at the filtered output frequency for a certain time period, and the inverter 1 outputs the output frequency. I can keep it.

When the set operation mode is 5, the control unit 13 transmits an operation command and a frequency command to the PWM control unit 20 so that the inverter 1 operates according to the set frequency, and the inverter 1 transmits the operating frequency at the set frequency. I can keep it.

Even while controlling the inverter 1 according to the operation mode as described above, the controller 13 continuously checks whether the command loss is released (S35), and when the command loss is released, returning to the normal operation of the inverter 1. Control may be performed (S36).

However, if the command-initiated operation mode is 0 to 2, since the inverter 1 is tripped or stopped, the procedure for restarting the inverter 1 may or may not proceed.

In operation mode 3, when the command loss is released and the command frequency is updated, the control unit 13 transmits the operation command and the updated command frequency to the PWM control unit 20, and the inverter 1 uses the updated command frequency. You will be able to drive.

In the operation mode 4, when the command loss is released, the control unit 13 transmits the operation command and the command frequency to the PWM control unit 20 so as to operate at the command frequency when the command loss is canceled, and the inverter 1 It can be operated by the command frequency.

In operation mode 5, when the command loss is released, the control unit 13 transmits the operation command and the command frequency to the PWM control unit 20 to operate at the command frequency at the time of release of the command loss, and the inverter 1 It can be operated by the command frequency.

As described above, according to the present invention, the user can perform the continuous operation after the command loss according to the operation mode set in the case of the command loss, and monitor the release of the command loss continuously even after the command loss, and automatically switch after the command loss. Can be.

According to the present invention as described above, it is possible to continuously operate in the case of command loss without additional equipment is required by the inverter itself. Therefore, the user does not need the installation space of additional equipment and additional equipment, it is possible to reduce the installation cost by reducing the total cost of ownership (TCO) in terms of the overall system. In addition, in the case of command loss, the continuous operation is possible, so that an accident of the inverter system can be prevented, thereby providing stability of the system.

Although embodiments according to the present invention have been described above, these are merely exemplary, and it will be understood by those skilled in the art that various modifications and equivalent embodiments of the present invention are possible therefrom. Therefore, the true technical protection scope of the present invention will be defined by the following claims.

1: inverter 37: inverter section
10: main controller 20: PWM control unit
11: communication unit 12: user input unit
13: control unit 14: control unit
15: display unit

Claims (16)

In the inverter system comprising an inverter unit consisting of a plurality of switching elements and a PWM control unit for providing a gate voltage generated by a pulse width modulation (PWM) waveform to the plurality of switching elements, the apparatus for controlling the inverter,
A storage unit which stores parameters for a command loss determination operation of the inverter; And
A control unit for determining a command loss of the inverter and providing an operation command and a frequency command to the PWM control unit to continuously operate the inverter according to the parameter;
The parameter stored by the storage unit includes a command loss determination frequency,
If the output frequency of the inverter is greater than the command loss determination frequency, the control unit determines that the command loss,
The inverter,
An inverter unit;
A regenerative braking unit consuming the regenerative energy as a resistor DB R when the DC voltage rises due to the regenerative operation or the like is larger than the set voltage;
A current detector for detecting a current flowing in each of U, V, and W phases and providing the current to the controller; And
It includes a temperature detection unit for detecting the temperature of the switching element of the inverter unit provided to the control unit,
The parameter is
Command operation execution setting, command loss determination time, command loss determination delay time and command loss input setting,
The command setting execution operation parameter is
First operation mode for holding the input of the inverter upon command operation, Second operation mode for holding the output of the inverter upon operation, Third operation mode for operating the inverter according to the set frequency when command operation occurs And a fourth operation mode in which the inverter is left unattended, a fifth operation mode in which the inverter is stopped when commanded, and a sixth operation mode in which the inverter is decelerated according to a predetermined deceleration frequency.
delete The method of claim 1, wherein when the command loss input setting parameter is communication,
And the controller is configured to determine that the command is lost when the time of not receiving data from the upper control device is maintained for a time corresponding to the command loss determination time parameter.
The method of claim 1, wherein when the command loss input setting parameter is an analog input,
And the controller determines that the command is lost when the analog input of the inverter is out of the normal range for a time corresponding to the command loss determination time parameter.
The method of claim 3 or 4, wherein the control unit,
Command Loss Determination Inverter control device that determines the loss of command after the delay time has elapsed.
delete delete The method according to claim 1, wherein the command-executing operation setting parameter is a first operation mode.
And the control unit transmits an operation command and a frequency command to maintain the operation frequency of the inverter at the command frequency of the inverter upon command operation to the PWM control unit.
The method of claim 8, wherein the control unit,
When the command loss is released, the inverter control device for transmitting the operation command and the updated command frequency to the PWM control unit when the command frequency is updated.
The method according to claim 1, wherein the command on-run operation setting parameter is a second operation mode.
And the control unit transmits an operation command and a frequency command to maintain the operating frequency of the inverter at an output frequency of the inverter upon command operation to the PWM control unit.
The method of claim 10, wherein the control unit,
The inverter control device for transmitting the operation command and the command frequency to the PWM control unit to operate at the command frequency when the command loss is canceled when the command loss is released.
The method according to claim 1, wherein the command-executing operation setting parameter is a third operation mode.
And the control unit transmits an operation command and a frequency command to the PWM control unit so that the inverter operates at the set frequency.
The method of claim 12, wherein the control unit,
The inverter control device for transmitting the operation command and the command frequency to the PWM control unit to operate at the command frequency when the command loss is canceled when the command loss is released.
The method according to claim 1, wherein the command-executing operation setting parameter is a fourth operation mode.
The control unit, the inverter control device leaving the inverter.
The method according to claim 1, wherein the command on-run operation setting parameter is a fifth operation mode.
And the control unit transmits an operation command for generating a trip and causing the inverter to stop to the PWM control unit.
The method according to claim 1, wherein the command-executing operation setting parameter is a sixth operation mode.
And the control unit transmits an operation command and a frequency command to the PWM control unit so that the inverter operates at the deceleration frequency.

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