CN113690854B - Frequency converter protection device and method and frequency converter - Google Patents
Frequency converter protection device and method and frequency converter Download PDFInfo
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- CN113690854B CN113690854B CN202110936975.5A CN202110936975A CN113690854B CN 113690854 B CN113690854 B CN 113690854B CN 202110936975 A CN202110936975 A CN 202110936975A CN 113690854 B CN113690854 B CN 113690854B
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- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02H—EMERGENCY PROTECTIVE CIRCUIT ARRANGEMENTS
- H02H7/00—Emergency protective circuit arrangements specially adapted for specific types of electric machines or apparatus or for sectionalised protection of cable or line systems, and effecting automatic switching in the event of an undesired change from normal working conditions
- H02H7/10—Emergency protective circuit arrangements specially adapted for specific types of electric machines or apparatus or for sectionalised protection of cable or line systems, and effecting automatic switching in the event of an undesired change from normal working conditions for converters; for rectifiers
- H02H7/12—Emergency protective circuit arrangements specially adapted for specific types of electric machines or apparatus or for sectionalised protection of cable or line systems, and effecting automatic switching in the event of an undesired change from normal working conditions for converters; for rectifiers for static converters or rectifiers
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01D—MEASURING NOT SPECIALLY ADAPTED FOR A SPECIFIC VARIABLE; ARRANGEMENTS FOR MEASURING TWO OR MORE VARIABLES NOT COVERED IN A SINGLE OTHER SUBCLASS; TARIFF METERING APPARATUS; MEASURING OR TESTING NOT OTHERWISE PROVIDED FOR
- G01D21/00—Measuring or testing not otherwise provided for
- G01D21/02—Measuring two or more variables by means not covered by a single other subclass
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- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02H—EMERGENCY PROTECTIVE CIRCUIT ARRANGEMENTS
- H02H1/00—Details of emergency protective circuit arrangements
- H02H1/0007—Details of emergency protective circuit arrangements concerning the detecting means
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- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02H—EMERGENCY PROTECTIVE CIRCUIT ARRANGEMENTS
- H02H1/00—Details of emergency protective circuit arrangements
- H02H1/0061—Details of emergency protective circuit arrangements concerning transmission of signals
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- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02H—EMERGENCY PROTECTIVE CIRCUIT ARRANGEMENTS
- H02H7/00—Emergency protective circuit arrangements specially adapted for specific types of electric machines or apparatus or for sectionalised protection of cable or line systems, and effecting automatic switching in the event of an undesired change from normal working conditions
- H02H7/10—Emergency protective circuit arrangements specially adapted for specific types of electric machines or apparatus or for sectionalised protection of cable or line systems, and effecting automatic switching in the event of an undesired change from normal working conditions for converters; for rectifiers
- H02H7/12—Emergency protective circuit arrangements specially adapted for specific types of electric machines or apparatus or for sectionalised protection of cable or line systems, and effecting automatic switching in the event of an undesired change from normal working conditions for converters; for rectifiers for static converters or rectifiers
- H02H7/122—Emergency protective circuit arrangements specially adapted for specific types of electric machines or apparatus or for sectionalised protection of cable or line systems, and effecting automatic switching in the event of an undesired change from normal working conditions for converters; for rectifiers for static converters or rectifiers for inverters, i.e. dc/ac converters
- H02H7/1225—Emergency protective circuit arrangements specially adapted for specific types of electric machines or apparatus or for sectionalised protection of cable or line systems, and effecting automatic switching in the event of an undesired change from normal working conditions for converters; for rectifiers for static converters or rectifiers for inverters, i.e. dc/ac converters responsive to internal faults, e.g. shoot-through
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- General Physics & Mathematics (AREA)
- Electromagnetism (AREA)
- Analogue/Digital Conversion (AREA)
Abstract
The invention discloses a protection device and a method of a frequency converter and the frequency converter, wherein the device comprises: each sampling unit of more than two sampling units samples the to-be-measured value of the corresponding sampling point in the cabinet of the frequency converter to obtain an analog sampling value; the control unit is used for sending a selection instruction according to the sampling protection requirement on the frequency converter; the selection unit selects one analog sampling value from more than two analog sampling values obtained by sampling of more than two sampling units according to the selection instruction; and the control unit also determines whether the frequency converter fails according to the selected analog sampling value so as to execute a preset fault protection mechanism under the condition that the frequency converter fails. This scheme through utilizing control chip and analog quantity selection circuit, carries out the analog quantity sampling to different test point positions in the cabinet of converter, can save control chip's sampling channel, avoids control chip's sampling channel can not satisfy the sampling quantity demand of different test point positions.
Description
Technical Field
The invention belongs to the technical field of frequency converters, and particularly relates to a frequency converter protection device and method and a frequency converter, in particular to a device and method for carrying out isolation selection sampling protection on analog quantity of the frequency converter and the frequency converter.
Background
In a high-power central air-conditioning unit, a high-power frequency converter is required to realize frequency conversion control of a compressor in the central air-conditioning unit. When the motor in the compressor is controlled by the frequency converter, temperature sampling protection needs to be carried out on an electric component and a power module in a cabinet of the frequency converter, failure damage of the frequency converter power component and an electric component caused by overvoltage, overcurrent and overtemperature is prevented, and fault shutdown protection is carried out on the frequency converter. Sometimes, analog quantity sampling needs to be carried out on different test point positions in a cabinet of the frequency converter, but the control chip resource is limited, and the sampling channel possibly cannot meet the sampling quantity requirements of the different test point positions.
The above is only for the purpose of assisting understanding of the technical solution of the present invention, and does not represent an admission that the above is the prior art.
Disclosure of Invention
The invention aims to provide a protection device and a protection method of a frequency converter and the frequency converter, which are used for solving the problems that when analog quantity sampling is carried out on different test point positions in a cabinet of the frequency converter, a sampling channel of a control chip is limited, and the requirements of the sampling quantity of the different test point positions cannot be met.
The invention provides a protection device of a frequency converter, which comprises: the device comprises a sampling unit, a selection unit and a control unit; the number of the sampling units is the same as that of sampling channels of sampling points in a cabinet of the frequency converter, and the number of the sampling units is more than two; each sampling unit in more than two sampling units is configured to sample a to-be-measured value of a corresponding sampling point in a cabinet of the frequency converter to obtain an analog sampling value; the parameters to be measured of the sampling points are parameters used as basis for protecting the sampling points; the control unit is configured to send a selection instruction according to the sampling protection requirement of the frequency converter; the selection instruction is used for selecting one analog sampling value from more than two analog sampling values obtained by sampling more than two sampling units so as to protect the frequency converter according to the selected analog sampling value; the selecting unit is configured to select one analog sampling value from more than two analog sampling values sampled by more than two sampling units according to the selection instruction; the control unit is further configured to determine whether the frequency converter fails according to the selected one of the analog sampling values, so as to execute a preset fault protection mechanism in case of the frequency converter failing.
In some embodiments, the selecting instruction comprises: enable control signals and address control signals; the selection unit includes: an enabling module and a selecting module; wherein, the selecting unit, according to the selection instruction, selects one of the two or more analog sampling values sampled by the sampling unit, and includes: the enabling module is configured to generate an enabling signal according to the enabling control signal; the selection module is configured to select one analog sampling value from two or more analog sampling values sampled by two or more sampling units according to the enable signal and the address control signal.
In some embodiments, the enabling module comprises: a Schmitt inverter; the selection module comprises: an analog electronic switch; an input of the Schmitt inverter capable of receiving the enable control signal; the output end of the Schmitt phase inverter can be output to the enabling input end of the analog electronic switch; the output end of each sampling unit in more than two sampling units is output to the corresponding input end of the analog electronic switch; and the output end of the analog electronic switch can be output to the control unit.
In some embodiments, the selecting unit further comprises: a filtering module; the number of the filtering modules is the same as that of the sampling units; the selecting unit, according to the selection instruction, selects one of the more than two analog sampling values obtained by sampling of the more than two sampling units, and further includes: each filtering module is configured to filter corresponding analog sampling values of two or more analog sampling values sampled by two or more sampling units; the selection module is further configured to select one analog sampling value from two or more analog sampling values sampled by two or more sampling units according to the enable signal and the address control signal, and transmit a filtered value of the selected one analog sampling value to the control unit.
In some embodiments, further comprising: an isolation unit; the isolation unit is configured to isolate the analog sampling value selected by the selection unit.
In some embodiments, the isolation unit comprises: the linear isolation chip and its peripheral circuits.
In some embodiments, further comprising: at least one of a linear adjustment unit and a following and filtering unit; under the condition that the protection device of the frequency converter further comprises a linear adjusting unit, the linear adjusting unit is configured to linearly adjust the one analog sampling value selected by the selecting unit so as to adjust the voltage value of the one analog sampling value selected by the selecting unit to be within a set voltage range; under the condition that the protection device of the frequency converter further comprises a following and filtering unit, the following and filtering unit is configured to follow and filter one analog sampling value obtained by isolation of the isolation unit so as to process an error of a voltage value of the one analog sampling value obtained by isolation of the isolation unit to be within a set error range.
In some embodiments, wherein, in case that the protection device of the frequency converter further comprises a linear adjusting unit, the linear adjusting unit comprises: a first operational amplifier and its peripheral circuits; in case the protection device of the frequency converter further comprises a following and filtering unit, the following and filtering unit comprises: a second operational amplifier and its peripheral circuits.
In accordance with another aspect of the present invention, there is provided a frequency converter, comprising: the protection device of the frequency converter is described above.
Matching with the frequency converter, the invention also provides a protection method of the frequency converter, which comprises the following steps: sampling the to-be-measured value of a corresponding sampling point in a cabinet of the frequency converter through each of two sampling units to obtain an analog sampling value; the parameters to be measured of the sampling points are parameters used as basis for protecting the sampling points; sending a selection instruction according to the sampling protection requirement of the frequency converter through a control unit; the selection instruction is used for selecting one analog sampling value from more than two analog sampling values obtained by sampling of more than two sampling units so as to protect the frequency converter according to the selected analog sampling value; selecting one analog sampling value from more than two analog sampling values sampled by more than two sampling units through a selection unit according to the selection instruction; and determining whether the frequency converter fails or not through the control unit according to the selected analog sampling value so as to execute a preset fault protection mechanism under the condition that the frequency converter fails.
In some embodiments, the selecting instruction comprises: enable control signals and address control signals; through the selecting element, according to the selection instruction, select one in the more than two of the analog sampling value that the sampling unit sampling got more than two the analog sampling value includes: generating, by an enable module, an enable signal according to the enable control signal; and selecting one analog sampling value from more than two analog sampling values obtained by sampling of more than two sampling units through a selection module according to the enable signal and the address control signal.
In some embodiments, at least one of the following processing conditions is also included: the first processing case: isolating one analog sampling value selected by the selection unit through an isolation unit; second case of treatment: the analog sampling value selected and obtained by the selection unit is linearly adjusted through a linear adjustment unit, so that the voltage value of the analog sampling value selected and obtained by the selection unit is adjusted to be within a set voltage range; the third treatment case: through the following and filtering unit, the isolating unit isolates one analog sampling value to follow and filter, so that the error of the voltage value of the analog sampling value isolated by the isolating unit is processed to be within a set error range.
Therefore, according to the scheme of the invention, the enabling control signal and the address control signal are sent to the analog quantity selection circuit through the I/O pin of the control chip, and the analog quantity selection circuit selects the channel to be sampled according to the address control signal, so that the control chip and the analog quantity selection circuit are utilized to sample analog quantities of different test point positions in the cabinet of the frequency converter, the sampling channel of the control chip can be saved, and the sampling channel of the control chip can be prevented from being incapable of meeting the sampling quantity requirements of the different test point positions.
Additional features and advantages of the invention will be set forth in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention.
The technical solution of the present invention is further described in detail by the accompanying drawings and embodiments.
Drawings
Fig. 1 is a schematic structural diagram of an embodiment of a protection device of a frequency converter according to the present invention;
FIG. 2 is a schematic structural diagram of an embodiment of a device for isolating, selecting and sampling an analog quantity of a frequency converter;
FIG. 3 is a schematic flow chart diagram illustrating an embodiment of a method for performing isolated selective sampling protection on an analog signal of a frequency converter;
FIG. 4 is a diagram illustrating an embodiment of an analog selection circuit;
FIG. 5 is a schematic diagram of an embodiment of an isolated sampling circuit;
FIG. 6 is a schematic structural diagram of an embodiment of a control chip;
fig. 7 is a schematic flowchart of a protection method for a frequency converter according to an embodiment of the present invention;
fig. 8 is a schematic flowchart illustrating an embodiment of selecting one analog sample value from two or more analog sample values sampled by two or more sampling units according to the protection method of the frequency converter of the present invention.
Detailed Description
In order to make the objects, technical solutions and advantages of the present invention more apparent, the technical solutions of the present invention will be clearly and completely described below with reference to the specific embodiments of the present invention and the accompanying drawings. It is to be understood that the described embodiments are merely exemplary of the invention, and not restrictive of the full scope of the invention. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.
In consideration of the fact that when analog quantity sampling is carried out on different test point locations in a cabinet of the frequency converter, the control chip resources are limited, and the sampling channel possibly cannot meet the sampling quantity requirements of the different test point locations. In addition, in the process of sampling analog quantity at different test point positions in the cabinet of the frequency converter, common electrical connection exists between the digital circuit of the control chip and sampling analog signals of the sampling channel, and mutual interference and influence may exist.
According to an embodiment of the present invention, there is provided a protection apparatus of a frequency converter. Referring to fig. 1, a schematic diagram of an embodiment of the apparatus of the present invention is shown. The protection device of the frequency converter can comprise: the device comprises a sampling unit, a selection unit and a control unit. A sampling unit, such as a sensor. And a selection unit, such as an analog selection circuit. And a control unit, such as a control chip. The number of the sampling units is the same as that of sampling channels of sampling points in the cabinet of the frequency converter, and the number of the sampling units is more than two.
Each sampling unit in more than two sampling units is configured to sample a to-be-measured value of a corresponding sampling point in a cabinet of the frequency converter to obtain an analog sampling value; the parameter to be measured of the sampling point is a parameter used as a basis for protecting the sampling point (for example, the sampling point is converted into an analog voltage signal).
The control unit is configured to send a selection instruction according to the sampling protection requirement of the frequency converter. The selection instruction is used for selecting one analog sampling value from more than two analog sampling values obtained by sampling of more than two sampling units so as to protect the frequency converter according to the selected one analog sampling value.
The selection unit is configured to select one analog sampling value from more than two analog sampling values sampled by more than two sampling units according to the selection instruction, and transmit the selected one analog sampling value to the control unit.
In some embodiments, the selecting instruction comprises: enable control signals and address control signals.
The selection unit includes: an enabling module and a selecting module.
Wherein, the selecting unit, according to the selection instruction, selects one of the two or more analog sampling values sampled by the sampling unit, and includes:
the enabling module is configured to generate an enabling signal according to the enabling control signal.
The selection module is configured to select one analog sampling value from more than two analog sampling values sampled by more than two sampling units according to the enable signal and the address control signal, and transmit the selected one analog sampling value to the control unit.
According to the scheme, the enabling control signal and the address control signal are sent to the analog quantity selection circuit through the I/O pin of the control chip, the analog quantity selection circuit selects the channel required to be sampled according to the address control signal, the sampling channel resource can be efficiently utilized, more analog quantity can be acquired for sampling protection, and the problem that the number of sampling paths is insufficient due to the fact that the single chip microcomputer sampling channel resource is limited is solved.
In some embodiments, the enabling module comprises: a schmitt inverter. The selection module comprises: an analog electronic switch.
And the input end of the Schmitt phase inverter can receive the enabling control signal. The output end of the schmitt phase inverter can be output to the enabling input end of the analog electronic switch (for example, an Inhibit pin of an 8-way analog electronic switch). And the output end of each sampling unit in the more than two sampling units is output to the corresponding input end of the analog electronic switch. And the output end of the analog electronic switch can be output to the control unit.
In the sampling protection circuit in the related scheme, an AD (i.e., analog quantity and digital quantity) sampling channel of a single chip microcomputer is mostly used to correspond to a value of a sampling point. Because the number of the sampling channels of the single chip microcomputer is limited, the sampling channel resources are occupied, and the sampling channels can not meet the requirements possibly due to the fact that the number of the samples is large. According to the scheme, the analog quantity selection circuit is built by using the analog electronic switch, the address control signal is generated through the GPIO (i.e. a universal input/output port) of the control chip, the analog electronic switch selects the corresponding analog signal channel to be conducted and connected into the output terminal Tout of the analog quantity selection circuit by detecting the signals of the address pins CtrlA, CtrlB and CtrlC of the control terminal of the analog quantity selection circuit, and therefore one sampling channel of the control chip is used for collecting different analog input quantities.
In some embodiments, the selecting unit further comprises: and a filtering module, such as an RC filtering circuit. The number of the filtering modules is the same as that of the sampling units.
The selecting unit, according to the selection instruction, select one in more than two analog sampling value that the sampling unit sampled and obtained more than two the analog sampling value still includes: each filtering module is configured to filter corresponding analog sampling values of the two or more analog sampling values sampled by the two or more sampling units.
Correspondingly, the selection module is further configured to select one analog sample value from two or more analog sample values sampled by two or more sampling units according to the enable signal and the address control signal, and transmit the filtered value of the selected one analog sample value to the control unit.
Fig. 4 is a schematic structural diagram of an embodiment of an analog quantity selection circuit. As shown in fig. 4, the analog quantity selection circuit includes: a Schmitt inverter, an 8-way analog electronic switch (such as a CD4051 analog electronic switch), and an RC filter module. Analog quantity voltage In the analog voltage value is accessed to an input In/output Out end of the 8-way analog electronic switch through an RC filter module (such as an RC filter module consisting of a resistor R1 and a capacitor C1, an RC filter module consisting of a resistor R2 and a capacitor C2, an RC filter module consisting of a resistor R3 and a capacitor C3, an RC filter module consisting of a resistor R4 and a capacitor C4 and the like) of the sensor through a first sampling channel T1, a second sampling channel T2, a third sampling channel T3 and a fourth sampling channel T4 of the sensor, address control signals sent by the 8-way analog electronic switch are received through control end pins rlA, CtrlB and CtrlC (corresponding to GPIO1, 2 and GPIO3 of the control chip) of the 8-way analog electronic switch, enabling signals (such as output signals of a chip select EN given by the Schmidt inverter based on chip select signals sent by the control chip) are selected according to truth values of the control chip table and output pins of the switch (such as In/Out end of the In/Out switch 8-way analog electronic switch (such as In 3 output signals sent by the Schmidt inverter) The connected Tout terminal) is connected, so that the input analog quantity voltage is transmitted to the sampling processing circuit for signal processing.
In the scheme of the invention, the enabling control signal and the address control signal are sent to the analog quantity selection circuit through the I/O pin of the control chip, the analog quantity selection circuit selects a channel required to be sampled according to the address control signal, the use of an analog processing circuit and components can be reduced, the influence of an analog input end and a sampling end of the control chip can be reduced, the value of multiple analog quantities can be stably acquired, the use efficiency of the control chip is improved, the size of a PCB (printed circuit board) is reduced, and the problem that multiple analog processing circuits are required for analog signals with different sampling paths is solved.
The control unit is further configured to determine whether the frequency converter fails according to the selected one of the analog sampling values, so as to execute a preset fault protection mechanism in case of the frequency converter failing, such as controlling a power device in the frequency converter to be turned off, and controlling a motor controlled by the frequency converter to be in a fault shutdown state.
According to the scheme of the invention, the channel to be acquired is selected through the selection unit such as the analog quantity selection circuit, and the analog channel selection for acquisition can be performed by utilizing an analog selection switch. By adding the analog quantity selection circuit, the corresponding analog channels are selected to be conducted as required, the problem that the number of sampling channels is insufficient due to resource limitation of the sampling channels of the single chip microcomputer can be solved, the occupation of the sampling channels used by the control chip can be effectively reduced, and analog quantity signals are transmitted to the control chip to be collected.
Considering that when analog signals are sampled, the problem of signal interference of common ground between digital signals and analog signals exists. Aspects of the invention, in some embodiments, further comprise: and an isolation unit.
The isolation unit is configured to isolate one analog sampling value selected by the selection unit, so as to isolate the one analog sampling value selected by the selection unit and transmit the isolated one analog sampling value to the control unit.
In the scheme of the invention, the sampling voltage is isolated and sampled by the isolation sampling circuit, so that the measured analog quantity signal is transmitted to the rear end from the front end through the linear optical coupler isolation and is input to the AD sampling channel in the control chip for sampling, the influence of the analog input end and the sampling end of the control chip can be reduced, the values of multiple paths of analog quantities are stably acquired, and the problem that the analog quantities and the sampling end need to be isolated is solved. That is to say, the optical isolation sampling circuit is added, so that the optical isolation is realized between the digital signal of the control chip and the sampling analog signal, and the common ground connection is cut off; therefore, the common ground interference of the analog signal to the digital signal is cut off, so that the analog signal can accurately reflect the sampling value, and the digital signal control is more stable.
In some embodiments, the isolation unit comprises: and linearly isolating the chip and peripheral circuits thereof.
According to the scheme of the invention, the linear optical coupler is used for carrying out isolation sampling, and a linear optical coupler isolation sampling circuit can be used for carrying out isolation sampling. Keep apart through the opto-coupler, can reduce the influence that the front end brought, can solve the analog signal to different sampling way numbers and need multichannel analog processing circuit, the analog quantity needs the problem of keeping apart with the sampling end.
In some embodiments, further comprising: at least one of a linear adjustment unit and a following and filtering unit.
Under the condition that the protection device of the frequency converter further comprises a linear adjusting unit, the linear adjusting unit is configured to linearly adjust the analog sampling value selected by the selecting unit so as to adjust the voltage value of the analog sampling value selected by the selecting unit to be within a set voltage range, and then isolate the analog sampling value selected by the selecting unit through the isolating unit.
Under the condition that the protection device of the frequency converter further comprises a following and filtering unit, the following and filtering unit is configured to follow and filter one analog sampling value obtained by isolation of the isolation unit so as to process an error of a voltage value of the analog sampling value obtained by isolation of the isolation unit to a set error range, and then transmit the error to the control unit.
Fig. 2 is a schematic structural diagram of an embodiment of a device for performing isolation-based sampling protection on an analog quantity of a frequency converter. As shown in fig. 2, the device for isolating, selecting and sampling the analog quantity of the frequency converter includes: the device comprises a sensor, an analog quantity selection circuit, a sampling processing circuit and a control chip. The sensor can convert the signal to be measured into an analog voltage signal, for example, by using a current, voltage, temperature sensor, and the like, and correspondingly measuring the current, voltage, temperature and waiting for measurement. And the analog quantity selection circuit can select a required sampling channel. And the sampling processing circuit can perform isolation processing according to the sampling value output by the analog quantity selection circuit and output an AD sampling signal to the control chip. The control signal can judge whether the frequency converter has a fault according to the AD sampling signal so as to control a power device in the frequency converter to be closed under the condition that the frequency converter has the fault and control the motor to be in fault shutdown.
According to the scheme, the analog signals are processed through the operational amplifier, so that the circuit influence of the front end and the chip end can be reduced, and the stability is improved. Wherein, handle analog signal through fortune is put, include: the input side RC has a filtering effect, the operational amplifier is used as a feedback regulation function of the comparator, and the stability of the analog signal is improved.
In some embodiments, wherein, in case that the protection device of the frequency converter further comprises a linear adjusting unit, the linear adjusting unit comprises: the first operational amplifier and its peripheral circuits, such as the operational amplifier U1 and its peripheral circuits.
In the case that the protection device of the frequency converter further comprises a following and filtering unit, the following and filtering unit comprises: a second operational amplifier and peripheral circuits thereof.
Fig. 5 is a schematic structural diagram of an embodiment of an isolated sampling circuit. As shown in fig. 5, an isolated sampling circuit includes: an operational amplifier U1, a linear optocoupler chip (such as an optocoupler chip with the type of IC IL 300-E), an operational amplifier U2 and peripheral circuits (such as a resistor R and a capacitor C). In the isolated sampling circuit shown in fig. 5, the analog voltage input through the operational amplifier U1 is linearly transformed to transform the collected analog voltage to a reasonable voltage through the operational amplifier U1 and its peripheral circuits. And then the converted voltage value is transmitted to the output end of the linear optical coupler from the front end isolation end through the linear optical coupler chip and a peripheral circuit thereof to eliminate the influence between the front end and the rear end, and the converted voltage value is processed into stable voltage through a voltage follower (such as the voltage follower formed by an operational amplifier U2 and the peripheral circuit thereof) and a filter circuit (such as the filter circuit formed by a resistor R and a capacitor C) and is output to an AD sampling pin of a control chip, so that a plurality of analog quantities are acquired through the pin of one sampling channel.
Fig. 3 is a schematic flowchart of an embodiment of a method for performing isolation-selective sampling protection on an analog quantity of a frequency converter. As shown in fig. 3, the method for performing isolation selection sampling protection on the analog quantity of the frequency converter includes:
and step 1, starting sampling. Specifically, the sampling amount is converted into an analog voltage value in proportional relation thereto by the sensor.
And 2, transmitting the analog voltage value to an analog quantity selection circuit.
And 4, judging whether the sampling voltage is larger than a reference range or not through software protection of a control chip, and if the sampling voltage exceeds the set range, closing a PWM (pulse width modulation) wave output by an EPWM (enhanced pulse width modulator) to realize fault shutdown control. For example: and comparing the sampled voltage value with a set protection value, and performing fault shutdown if the sampled voltage value exceeds the set protection value.
The invention provides a scheme for carrying out sampling protection through an analog electronic switch, which is characterized in that an enabling control signal and an address control signal are sent to an analog quantity selection circuit through an I/O pin of a control chip, the analog quantity selection circuit selects a channel to be sampled according to the address control signal, a sampling voltage passes through an isolation sampling circuit, a measured analog quantity signal is transmitted to the rear end from the front end through a linear optical coupler in an isolation mode, the analog quantity signal is input to an AD sampling channel in the control chip for sampling, the control chip judges whether a sampling value is in a reference value range, and if the sampling value exceeds the range, a PWM wave is closed to carry out fault shutdown protection.
By adopting the technical scheme of the invention, the enabling control signal and the address control signal are sent to the analog quantity selection circuit through the I/O pin of the control chip, and the analog quantity selection circuit selects the channel to be sampled according to the address control signal, so that the control chip and the analog quantity selection circuit are utilized to sample the analog quantity of different test point positions in the cabinet of the frequency converter, the sampling channel of the control chip can be saved, and the sampling channel of the control chip can be prevented from being incapable of meeting the sampling quantity requirements of the different test point positions.
According to an embodiment of the present invention, there is also provided a frequency converter corresponding to a protection device of the frequency converter. The frequency converter may include: the protection device of the frequency converter is described above.
Since the processing and functions implemented by the frequency converter of this embodiment substantially correspond to the embodiments, principles, and examples of the foregoing apparatus, reference may be made to the related descriptions in the foregoing embodiments without being detailed in the description of this embodiment.
By adopting the technical scheme of the invention, the enabling control signal and the address control signal are sent to the analog quantity selection circuit through the I/O pin of the control chip, and the analog quantity selection circuit selects the channel to be sampled according to the address control signal, so that the sampling channel resource can be efficiently utilized, and more analog quantity can be acquired for sampling protection.
According to an embodiment of the present invention, a method for protecting a frequency converter corresponding to the frequency converter is also provided, as shown in fig. 7, which is a schematic flowchart of an embodiment of the method of the present invention. The protection method of the frequency converter can comprise the following steps: step S110 to step S140.
Step S110, sampling the to-be-measured value of the corresponding sampling point in the cabinet of the frequency converter through each sampling unit of the two sampling units to obtain an analog sampling value; the parameter to be measured of the sampling point is a parameter used as a basis for protecting the sampling point (for example, converting the parameter to be measured into an analog voltage signal).
And step S120, sending a selection instruction according to the sampling protection requirement of the frequency converter through a control unit. The selection instruction is used for selecting one analog sampling value from more than two analog sampling values obtained by sampling of more than two sampling units so as to protect the frequency converter according to the selected one analog sampling value.
Step S130, selecting one analog sampling value from more than two analog sampling values obtained by sampling of more than two sampling units through a selection unit according to the selection instruction, and transmitting the selected analog sampling value to the control unit.
In some embodiments, the selection instruction comprises: enable control signals and address control signals.
The selection unit includes: an enabling module and a selecting module.
In step S130, a specific process of selecting one analog sample value from two or more analog sample values obtained by sampling by two or more sampling units according to the selection instruction by a selection unit is described in the following exemplary description.
With reference to the flowchart of fig. 8, a specific process for selecting one analog sample value from two or more analog sample values sampled by two or more sampling units is further described, which includes: step S210 and step S220.
And step S210, generating an enabling signal according to the enabling control signal through an enabling module.
Step S220, selecting one analog sampling value from more than two analog sampling values obtained by sampling of more than two sampling units through a selection module according to the enabling signal and the address control signal, and transmitting the selected analog sampling value to the control unit.
According to the scheme, the enabling control signal and the address control signal are sent to the analog quantity selection circuit through the I/O pin of the control chip, the analog quantity selection circuit selects the channel required to be sampled according to the address control signal, the sampling channel resource can be efficiently utilized, more analog quantity can be acquired for sampling protection, and the problem that the number of sampling paths is insufficient due to the fact that the single chip microcomputer sampling channel resource is limited is solved.
In the sampling protection circuit in the related scheme, an AD (i.e., analog quantity and digital quantity) sampling channel of a single chip microcomputer is mostly used to correspond to a value of a sampling point. Because the number of the sampling channels of the single chip microcomputer is limited, the sampling channel resources are occupied, and the sampling channels can not meet the requirements possibly due to the fact that the number of the samples is large. According to the scheme, the analog quantity selection circuit is built by using the analog electronic switch, the address control signal is generated through the GPIO (i.e. a universal input/output port) of the control chip, the analog electronic switch selects the corresponding analog signal channel to be conducted and connected into the output terminal Tout of the analog quantity selection circuit by detecting the signals of the address pins CtrlA, CtrlB and CtrlC of the control terminal of the analog quantity selection circuit, and therefore one sampling channel of the control chip is used for collecting different analog input quantities.
Fig. 4 is a schematic structural diagram of an embodiment of an analog quantity selection circuit. As shown in fig. 4, the analog quantity selection circuit includes: a Schmitt inverter, an 8-path analog electronic switch and an RC filtering module. Analog quantity voltage In analog voltage values is accessed to an input In/output Out end of an 8-way analog electronic switch through an RC filter module (such as an RC filter module consisting of a resistor R1 and a capacitor C1, an RC filter module consisting of a resistor R2 and a capacitor C2, an RC filter module consisting of a resistor R3 and a capacitor C3, an RC filter module consisting of a resistor R4 and a capacitor C4 and the like) of the sensor through a first sampling channel T1, a second sampling channel T2, a third sampling channel T3 and a fourth sampling channel T4 of the sensor, an address control signal sent by the control chip is received by control end pins A, CtrlB and CtrlC (corresponding to pins GPIO1, 2 and GPIO3 of the control chip) of the 8-way analog electronic switch, an enable signal (such as an output signal of an In/Out end on the basis of the control chip selection signal EN of the Schmitt inverter) is combined, and an In/Out enable signal (such as an In/Out end pin 3 of the In/Out end of the Schmitt inverter) is selected according to a truth table of the control chip The connected terminal Tout) is connected, so that the input analog quantity voltage is transmitted to the sampling processing circuit for signal processing.
In the scheme of the invention, the enabling control signal and the address control signal are sent to the analog quantity selection circuit through the I/O pin of the control chip, the analog quantity selection circuit selects a channel to be sampled according to the address control signal, the use of an analog processing circuit and components can be reduced, the influence of an analog input end and a sampling end of the control chip can be reduced, the values of multiple analog quantities can be acquired more stably, the use efficiency of the control chip is improved, the size of a PCB (printed circuit board) is reduced, and the problem that the analog signals with different sampling paths need multiple analog processing circuits is solved.
Step S140, determining, by the control unit, whether the frequency converter fails according to the selected analog sampling value, so as to execute a preset fault protection mechanism when the frequency converter fails, for example, to control a power device in the frequency converter to be turned off, and to control a motor controlled by the frequency converter to be stopped due to a fault.
A sampling unit, such as a sensor. And a selection unit, such as an analog selection circuit. And a control unit, such as a control chip. The number of the sampling units is the same as that of sampling channels of sampling points in the frequency converter cabinet, and the number of the sampling units is more than two.
According to the scheme of the invention, the channel to be acquired is selected through the selection unit such as the analog quantity selection circuit, and the analog channel selection for acquisition can be performed by utilizing an analog selection switch. By adding the analog quantity selection circuit, the corresponding analog channels are selected to be conducted as required, the problem that the number of sampling channels is insufficient due to resource limitation of the sampling channels of the single chip microcomputer can be solved, the occupation of the sampling channels used by the control chip can be effectively reduced, and analog quantity signals are transmitted to the control chip to be collected.
In some embodiments, at least one of the following processing conditions is also included:
the first processing case: and isolating one analog sampling value selected by the selection unit through an isolation unit, so that the analog sampling value selected by the selection unit is isolated and then transmitted to the control unit.
In the scheme of the invention, the sampling voltage is isolated and sampled by the isolation sampling circuit, so that the measured analog quantity signal is transmitted to the rear end from the front end through the linear optical coupler isolation and is input to the AD sampling channel in the control chip for sampling, the influence of the analog input end and the sampling end of the control chip can be reduced, the values of multiple paths of analog quantities are stably acquired, and the problem that the analog quantities and the sampling end need to be isolated is solved. That is to say, the isolation sampling is performed by a linear optical coupler, and may be performed by using a linear optical coupler isolation sampling circuit. Keep apart through the opto-coupler, can reduce the influence that the front end brought, can solve the analog signal to different sampling way numbers and need multichannel analog processing circuit, the problem that analog quantity and sampling end need keep apart.
Second case of treatment: and the analog sampling value selected and obtained by the selection unit is linearly adjusted through a linear adjustment unit so as to adjust the voltage value of the analog sampling value selected and obtained by the selection unit to a set voltage range, and then the analog sampling value selected and obtained by the selection unit is isolated through the isolation unit.
The third treatment case: through the following and filtering unit, the isolating unit isolates one analog sampling value to follow and filter, so that the error of the voltage value of the analog sampling value isolated by the isolating unit is processed to be within a set error range, and then the voltage value is transmitted to the control unit.
Fig. 2 is a schematic structural diagram of an embodiment of a device for performing isolation, selection and sampling protection on an analog quantity of a frequency converter. As shown in fig. 2, the device for isolating, selecting and sampling the analog quantity of the frequency converter includes: the device comprises a sensor, an analog quantity selection circuit, a sampling processing circuit and a control chip. And the sensor can convert the signal to be measured into an analog voltage signal. And the analog quantity selection circuit can select a required sampling channel. And the sampling processing circuit can perform isolation processing according to the sampling value output by the analog quantity selection circuit and output an AD sampling signal to the control chip. The control signal can judge whether the frequency converter has a fault according to the AD sampling signal so as to control a power device in the frequency converter to be closed under the condition that the frequency converter has the fault and control the motor to be in fault shutdown.
According to the scheme, the analog signals are processed through the operational amplifier, so that the circuit influence of the front end and the chip end can be reduced, and the stability is improved.
Fig. 5 is a schematic structural diagram of an embodiment of an isolated sampling circuit. As shown in fig. 5, an isolated sampling circuit includes: operational amplifier U1, linear optocoupler chip, operational amplifier U2 and its peripheral circuits (such as resistor R, capacitor C, etc.). In the isolated sampling circuit shown in fig. 5, the analog voltage input by the operational amplifier U1 is linearly converted to convert the collected analog voltage to a reasonable voltage by the operational amplifier U1 and its peripheral circuits; and then the converted voltage value is transmitted to the output end of the linear optical coupler from the front end isolation end through the linear optical coupler chip and a peripheral circuit thereof to eliminate the influence between the front end and the rear end, and the converted voltage value is processed into stable voltage through a voltage follower (such as the voltage follower formed by an operational amplifier U2 and the peripheral circuit thereof) and a filter circuit (such as the filter circuit formed by a resistor R and a capacitor C) and is output to an AD sampling pin of a control chip, so that a plurality of analog quantities are acquired through the pin of one sampling channel.
Fig. 3 is a schematic flowchart of an embodiment of a method for performing isolation-selective sampling protection on an analog quantity of a frequency converter. As shown in fig. 3, the method for isolating, selecting and sampling the analog quantity of the frequency converter includes:
and step 1, starting sampling. Specifically, the sample amount is converted by the sensor into an analog voltage value proportional thereto.
And 2, transmitting the analog voltage value to an analog quantity selection circuit.
And 4, judging whether the sampling voltage is larger than a reference range or not through software protection of a control chip, and if the sampling voltage exceeds the set range, closing a PWM wave output by an EPWM (enhanced pulse width modulator) to realize fault shutdown control.
The invention provides a scheme for carrying out sampling protection through an analog electronic switch, which is characterized in that an enabling control signal and an address control signal are sent to an analog quantity selection circuit through an I/O pin of a control chip, the analog quantity selection circuit selects a channel to be sampled according to the address control signal, a sampling voltage passes through an isolation sampling circuit, a measured analog quantity signal is transmitted to the rear end from the front end through a linear optical coupler in an isolation mode, the analog quantity signal is input to an AD sampling channel in the control chip for sampling, the control chip judges whether a sampling value is in a reference value range, and if the sampling value exceeds the range, a PWM wave is closed to carry out fault shutdown protection.
Since the processing and functions implemented by the method of this embodiment substantially correspond to the embodiments, principles and examples of the frequency converter, reference may be made to relevant descriptions in the foregoing embodiments without being detailed in the description of this embodiment, which is not described herein again.
By adopting the technical scheme of the embodiment, the enabling control signal and the address control signal are sent to the analog quantity selection circuit through the I/O pin of the control chip, and the analog quantity selection circuit selects the channel required to be sampled according to the address control signal, so that the occupation of the sampling channel used by the control chip can be effectively reduced, and the analog quantity signal is transmitted to the control chip for collection.
In summary, it is readily understood by those skilled in the art that the advantageous modes described above can be freely combined and superimposed without conflict.
The above description is only an example of the present invention, and is not intended to limit the present invention, and various modifications and changes may be made to the present invention by those skilled in the art. Any modification, equivalent replacement, or improvement made within the spirit and principle of the present invention should be included in the scope of the claims of the present invention.
Claims (10)
1. A protection device of a frequency converter is characterized by comprising: the device comprises a sampling unit, a selection unit and a control unit; the number of the sampling units is the same as that of sampling channels of sampling points in a cabinet of the frequency converter, and the number of the sampling units is more than two; wherein, the first and the second end of the pipe are connected with each other,
each of the more than two sampling units is configured to sample a to-be-measured value of a corresponding sampling point in a cabinet of the frequency converter to obtain an analog sampling value; the parameters to be measured of the sampling points are parameters used as bases for protecting the sampling points;
the control unit is configured to send a selection instruction according to the sampling protection requirement of the frequency converter; the selection instruction is used for selecting one analog sampling value from more than two analog sampling values obtained by sampling more than two sampling units so as to protect the frequency converter according to the selected analog sampling value; the selection instruction comprises: enable control signals and address control signals;
the selecting unit is configured to select one analog sampling value from more than two analog sampling values sampled by more than two sampling units according to the selection instruction; the selection unit includes: an enabling module and a selecting module; wherein, the selecting unit, according to the selection instruction, selects one of the two or more analog sampling values sampled by the sampling unit, and includes: the enabling module is configured to generate an enabling signal according to the enabling control signal; the selection module is configured to select one analog sampling value from more than two analog sampling values sampled by more than two sampling units according to the enable signal and the address control signal;
the control unit is further configured to determine whether the frequency converter fails according to the selected one of the analog sampling values, so as to execute a preset fault protection mechanism in case of the frequency converter failing.
2. The protection device of a frequency converter according to claim 1, wherein the enabling module comprises: a Schmitt inverter; the selection module comprises: an analog electronic switch;
an input of the Schmitt inverter capable of receiving the enable control signal; the output end of the Schmitt phase inverter can be output to the enabling input end of the analog electronic switch; the output end of each sampling unit in more than two sampling units is output to the corresponding input end of the analog electronic switch; and the output end of the analog electronic switch can be output to the control unit.
3. The protection device of a frequency converter according to claim 1, wherein the selection unit further comprises: a filtering module; the number of the filtering modules is the same as that of the sampling units;
the selecting unit, according to the selection instruction, selects one of the more than two analog sampling values obtained by sampling of the more than two sampling units, and further includes:
each filtering module is configured to filter corresponding analog sampling values of two or more analog sampling values sampled by two or more sampling units;
the selection module is further configured to select one analog sampling value from two or more analog sampling values sampled by two or more sampling units according to the enable signal and the address control signal, and transmit a filtered value of the selected one analog sampling value to the control unit.
4. A protection arrangement for a frequency converter according to any one of claims 1-3, characterized in that it further comprises: an isolation unit;
the isolation unit is configured to isolate the analog sampling value selected by the selection unit.
5. The protection device of a frequency converter according to claim 4, wherein the isolation unit comprises: and linearly isolating the chip and peripheral circuits thereof.
6. The protection device of a frequency converter according to claim 4, further comprising: at least one of a linear adjustment unit and a following and filtering unit;
wherein, the first and the second end of the pipe are connected with each other,
in the case that the protection device of the frequency converter further comprises a linear adjusting unit, the linear adjusting unit is configured to linearly adjust the one analog sampling value selected by the selecting unit so as to adjust the voltage value of the one analog sampling value selected by the selecting unit to be within a set voltage range;
under the condition that the protection device of the frequency converter further comprises a following and filtering unit, the following and filtering unit is configured to follow and filter one analog sampling value obtained by isolation of the isolation unit so as to process an error of a voltage value of the one analog sampling value obtained by isolation of the isolation unit to be within a set error range.
7. The protection device of frequency converter according to claim 4, wherein,
in case the protection device of the frequency converter further comprises a linear adjustment unit, the linear adjustment unit comprises: a first operational amplifier and its peripheral circuits;
in case the protection device of the frequency converter further comprises a following and filtering unit, the following and filtering unit comprises: a second operational amplifier and peripheral circuits thereof.
8. A frequency converter, comprising: a protection device of a frequency converter according to any one of claims 1 to 7.
9. A protection method of a frequency converter is characterized by comprising the following steps:
sampling the to-be-measured value of a corresponding sampling point in a cabinet of the frequency converter through each of two sampling units to obtain an analog sampling value; the parameters to be measured of the sampling points are parameters used as bases for protecting the sampling points;
sending a selection instruction according to the sampling protection requirement of the frequency converter through a control unit; the selection instruction is used for selecting one analog sampling value from more than two analog sampling values obtained by sampling more than two sampling units so as to protect the frequency converter according to the selected analog sampling value; the selection instruction comprises: enable control signals and address control signals;
selecting one analog sampling value from more than two analog sampling values sampled by more than two sampling units through a selection unit according to the selection instruction; through the selecting element, according to the selection instruction, select one in the more than two of the analog sampling value that the sampling unit sampling got more than two the analog sampling value includes: generating, by an enable module, an enable signal according to the enable control signal; selecting one analog sampling value from more than two analog sampling values obtained by sampling more than two sampling units through a selection module according to the enable signal and the address control signal;
and determining whether the frequency converter fails or not through the control unit according to the selected analog sampling value so as to execute a preset fault protection mechanism under the condition that the frequency converter fails.
10. The method for protecting the frequency converter according to claim 9, further comprising at least one of the following processing conditions:
the first processing case: isolating one analog sampling value selected by the selection unit through an isolation unit;
second case of treatment: the analog sampling value selected and obtained by the selection unit is linearly adjusted through a linear adjustment unit, so that the voltage value of the analog sampling value selected and obtained by the selection unit is adjusted to be within a set voltage range;
the third treatment case: through the following and filtering unit, the isolating unit isolates one analog sampling value to follow and filter, so that the error of the voltage value of the analog sampling value isolated by the isolating unit is processed to be within a set error range.
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Citations (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP0598374A2 (en) * | 1992-11-16 | 1994-05-25 | Kabushiki Kaisha Kenwood | Sampling frequency converter |
| JP2007306638A (en) * | 2006-05-08 | 2007-11-22 | Mitsubishi Electric Corp | Sampling frequency converter |
| CN101977021A (en) * | 2010-10-22 | 2011-02-16 | 电子科技大学 | Multi-channel digital down-conversion device |
| CN103762555A (en) * | 2014-01-03 | 2014-04-30 | 北京合康亿盛变频科技股份有限公司 | Over-current protection device and protection method for frequency converter |
| CN107783025A (en) * | 2017-09-22 | 2018-03-09 | 深圳芯邦科技股份有限公司 | A kind of test system and method based on chip port current driving ability |
| CN111900699A (en) * | 2020-08-03 | 2020-11-06 | 珠海格力电器股份有限公司 | Sampling protection device, frequency converter and sampling protection method thereof |
Family Cites Families (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2010068416A (en) * | 2008-09-12 | 2010-03-25 | Panasonic Corp | Sampling frequency conversion device, and signal reproduction device |
| CN105720797A (en) * | 2016-05-03 | 2016-06-29 | 北京森源东标电气有限公司 | High voltage cascading four-quadrant frequency converter unit controller |
| CN109038476A (en) * | 2018-08-08 | 2018-12-18 | 杭州先途电子有限公司 | A kind of current foldback circuit and controller |
| CN111525927A (en) * | 2020-04-24 | 2020-08-11 | 希翼微电子(嘉兴)有限公司 | System and method capable of enhancing ADC multichannel sampling precision |
| CN111769747B (en) * | 2020-06-15 | 2021-08-31 | 珠海格力电器股份有限公司 | Control device and method of frequency converter and frequency converter |
| CN112234581A (en) * | 2020-09-17 | 2021-01-15 | 珠海格力电器股份有限公司 | Bus protection device and method of frequency converter and frequency converter |
-
2021
- 2021-08-16 CN CN202110936975.5A patent/CN113690854B/en active Active
Patent Citations (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP0598374A2 (en) * | 1992-11-16 | 1994-05-25 | Kabushiki Kaisha Kenwood | Sampling frequency converter |
| JP2007306638A (en) * | 2006-05-08 | 2007-11-22 | Mitsubishi Electric Corp | Sampling frequency converter |
| CN101977021A (en) * | 2010-10-22 | 2011-02-16 | 电子科技大学 | Multi-channel digital down-conversion device |
| CN103762555A (en) * | 2014-01-03 | 2014-04-30 | 北京合康亿盛变频科技股份有限公司 | Over-current protection device and protection method for frequency converter |
| CN107783025A (en) * | 2017-09-22 | 2018-03-09 | 深圳芯邦科技股份有限公司 | A kind of test system and method based on chip port current driving ability |
| CN111900699A (en) * | 2020-08-03 | 2020-11-06 | 珠海格力电器股份有限公司 | Sampling protection device, frequency converter and sampling protection method thereof |
Non-Patent Citations (1)
| Title |
|---|
| 宽带数字下变频器的一种新的实现结构;张玉良 等;《电路与系统学报》;电路与系统学报;20030831;第8卷(第4期);第95-99页 * |
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