CN117254747A - Temperature detection device of frequency converter, control method thereof and frequency converter - Google Patents

Temperature detection device of frequency converter, control method thereof and frequency converter Download PDF

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Publication number
CN117254747A
CN117254747A CN202311541359.5A CN202311541359A CN117254747A CN 117254747 A CN117254747 A CN 117254747A CN 202311541359 A CN202311541359 A CN 202311541359A CN 117254747 A CN117254747 A CN 117254747A
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China
Prior art keywords
temperature
module
path
frequency converter
over
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CN202311541359.5A
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Chinese (zh)
Inventor
余浩燃
张艳婷
张良浩
李思琪
王云骏
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Gree Electric Appliances Inc of Zhuhai
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Gree Electric Appliances Inc of Zhuhai
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Priority to CN202311541359.5A priority Critical patent/CN117254747A/en
Publication of CN117254747A publication Critical patent/CN117254747A/en
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Classifications

    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02P—CONTROL OR REGULATION OF ELECTRIC MOTORS, ELECTRIC GENERATORS OR DYNAMO-ELECTRIC CONVERTERS; CONTROLLING TRANSFORMERS, REACTORS OR CHOKE COILS
    • H02P29/00—Arrangements for regulating or controlling electric motors, appropriate for both AC and DC motors
    • H02P29/60—Controlling or determining the temperature of the motor or of the drive
    • H02P29/64—Controlling or determining the temperature of the winding
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01K—MEASURING TEMPERATURE; MEASURING QUANTITY OF HEAT; THERMALLY-SENSITIVE ELEMENTS NOT OTHERWISE PROVIDED FOR
    • G01K7/00—Measuring temperature based on the use of electric or magnetic elements directly sensitive to heat ; Power supply therefor, e.g. using thermoelectric elements
    • G01K7/16—Measuring temperature based on the use of electric or magnetic elements directly sensitive to heat ; Power supply therefor, e.g. using thermoelectric elements using resistive elements
    • G01K7/22—Measuring temperature based on the use of electric or magnetic elements directly sensitive to heat ; Power supply therefor, e.g. using thermoelectric elements using resistive elements the element being a non-linear resistance, e.g. thermistor
    • G01K7/24—Measuring temperature based on the use of electric or magnetic elements directly sensitive to heat ; Power supply therefor, e.g. using thermoelectric elements using resistive elements the element being a non-linear resistance, e.g. thermistor in a specially-adapted circuit, e.g. bridge circuit
    • G01K7/25—Measuring temperature based on the use of electric or magnetic elements directly sensitive to heat ; Power supply therefor, e.g. using thermoelectric elements using resistive elements the element being a non-linear resistance, e.g. thermistor in a specially-adapted circuit, e.g. bridge circuit for modifying the output characteristic, e.g. linearising
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02H—EMERGENCY PROTECTIVE CIRCUIT ARRANGEMENTS
    • H02H5/00—Emergency protective circuit arrangements for automatic disconnection directly responsive to an undesired change from normal non-electric working conditions with or without subsequent reconnection
    • H02H5/04—Emergency protective circuit arrangements for automatic disconnection directly responsive to an undesired change from normal non-electric working conditions with or without subsequent reconnection responsive to abnormal temperature
    • H02H5/047—Emergency protective circuit arrangements for automatic disconnection directly responsive to an undesired change from normal non-electric working conditions with or without subsequent reconnection responsive to abnormal temperature using a temperature responsive switch
    • 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
    • H02H7/1216—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 AC-AC converters
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02P—CONTROL OR REGULATION OF ELECTRIC MOTORS, ELECTRIC GENERATORS OR DYNAMO-ELECTRIC CONVERTERS; CONTROLLING TRANSFORMERS, REACTORS OR CHOKE COILS
    • H02P27/00—Arrangements or methods for the control of AC motors characterised by the kind of supply voltage
    • H02P27/04—Arrangements or methods for the control of AC motors characterised by the kind of supply voltage using variable-frequency supply voltage, e.g. inverter or converter supply voltage
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01K—MEASURING TEMPERATURE; MEASURING QUANTITY OF HEAT; THERMALLY-SENSITIVE ELEMENTS NOT OTHERWISE PROVIDED FOR
    • G01K2205/00—Application of thermometers in motors, e.g. of a vehicle
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01K—MEASURING TEMPERATURE; MEASURING QUANTITY OF HEAT; THERMALLY-SENSITIVE ELEMENTS NOT OTHERWISE PROVIDED FOR
    • G01K2219/00—Thermometers with dedicated analog to digital converters

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  • Engineering & Computer Science (AREA)
  • Power Engineering (AREA)
  • Physics & Mathematics (AREA)
  • Nonlinear Science (AREA)
  • General Physics & Mathematics (AREA)
  • Protection Of Generators And Motors (AREA)

Abstract

The invention belongs to the field of frequency converters, and discloses a temperature detection device of a frequency converter, a control method thereof and the frequency converter, wherein the device comprises: obtaining more than two paths of temperature sampling signals through more than two temperature sampling modules; the temperature selecting module selects one path of temperature sampling signals from more than two paths of temperature sampling signals to output under the control of the current round of the motor controller, and the one path of temperature sampling signals are used as one path of temperature sampling signals obtained by current selection; and the motor controller is used for carrying out new current round of control on the temperature selection module based on one path of temperature sampling signals obtained by current selection, so that the temperature selection module carries out polling selection on more than two paths of temperature sampling signals to select the other path of temperature sampling signals to output, and the other path of temperature sampling signals are used as one path of temperature sampling signals obtained by new current selection, thereby carrying out polling control. According to the scheme, more than two paths of temperature sampling signals of the frequency converter are combined and output to one sampling port of the DSP chip, so that the sampling pressure is reduced.

Description

Temperature detection device of frequency converter, control method thereof and frequency converter
Technical Field
The invention belongs to the technical field of frequency converters, and particularly relates to a temperature detection device of a frequency converter, a control method of the temperature detection device and the frequency converter, and particularly relates to a multichannel temperature sampling and over-temperature protection device of the frequency converter, a control method of the multichannel temperature sampling and over-temperature protection device and the frequency converter.
Background
With the demands of people for higher rotation speed and efficiency of the motor, the frequency converter is required to provide higher operation frequency and more stable working state correspondingly. The frequency converter is used as a power supply system of the motor, temperature sampling is an important component part of the frequency converter, the operation conditions of the frequency converter and the motor can be known in real time by sampling and monitoring the temperature of each part of the frequency converter, and abnormal conditions of the frequency converter and the motor are timely adjusted so as to avoid burning caused by the fact that power devices in the frequency converter cannot dissipate heat in time.
The frequency converter needs multiple paths of sampling to meet the stable operation of the system, and the temperature sampling mode of the frequency converter in the related scheme adopts one path of sampling device to correspond to one sampling point, and each path of sampling device is independently input into the corresponding sampling port of the DSP chip. For a more complex motor control system, more sampling points occupy more sampling ports of a DSP chip, so that the sampling ports of the DSP are insufficient; in order to meet the design requirement, a plurality of DSP chips or more DSP chips with sampling ports replaced have to be used for sampling, resulting in an increase in production cost.
The foregoing is provided merely for the purpose of facilitating understanding of the technical solutions of the present invention and is not intended to represent an admission that the foregoing is prior art.
Disclosure of Invention
The invention aims to provide a temperature detection device of a frequency converter, a control method thereof and the frequency converter, which aim to solve the problem that the sampling pressure of the DSP chip is high because more sampling ports of the DSP chip are needed because the sampling device of each path of sampling device is independently input into the corresponding sampling port of the DSP chip in a corresponding sampling point of the frequency converter in a temperature sampling mode, and achieve the effect of reducing the sampling pressure of the DSP chip by combining and outputting more than two paths of temperature sampling signals of the frequency converter to one sampling port of the DSP chip.
The invention provides a temperature detection device of a frequency converter, comprising: the system comprises a temperature sampling module, a temperature selecting module and a motor controller; the number of the temperature sampling modules is more than two; each of the two or more temperature sampling modules is used for sampling the temperature of one temperature measuring position of a winding of a motor controlled by the frequency converter to obtain one path of temperature sampling signals; through more than two temperature sampling modules, more than two paths of temperature sampling signals can be obtained; the temperature selection module is used for selecting one path of temperature sampling signals from more than two paths of temperature sampling signals to output under the control of the current round of the motor controller, and taking the one path of temperature sampling signals as one path of temperature sampling signals obtained by current selection; and the motor controller is used for carrying out new current round control on the temperature selection module based on one path of temperature sampling signals obtained by current selection so as to enable the temperature selection module to carry out polling selection on more than two paths of temperature sampling signals to select the other path of temperature sampling signals to output, and the other path of temperature sampling signals are used as one path of temperature sampling signals obtained by new current selection so as to carry out polling control.
In some embodiments, each of the two or more temperature sampling modules comprises: the temperature sensing device comprises a first voltage dividing module, a second voltage dividing module, a third voltage dividing module, a temperature sensing module and a differential amplifying module; the temperature sensing module is arranged at one temperature measuring position of the winding of the motor controlled by the frequency converter and is used for sensing the temperature of the one temperature measuring position of the winding of the motor controlled by the frequency converter, and the temperature sensing module senses a voltage signal under the condition that the temperature of the one temperature measuring position of the winding of the motor controlled by the frequency converter changes; the power supply voltage is grounded after passing through the first voltage dividing module and the second voltage dividing module; the power supply voltage is grounded after passing through the third voltage dividing module and the temperature sensing module; the common end of the first voltage dividing module and the second voltage dividing module is connected to the inverting input end of the differential amplifying module; the common end of the third voltage dividing module and the temperature sensing module is connected to the non-inverting input end of the differential amplifying module; the first voltage dividing module, the second voltage dividing module, the third voltage dividing module and the temperature sensing module form a bridge structure; under the condition that the temperature sensing module senses a voltage signal, the bridge structure generates a voltage difference; the differential amplification module is used for outputting a path of voltage signal after differential amplification is carried out on the voltage difference input by the inverting input end of the differential amplification module and the non-inverting input end of the differential amplification module under the condition that the temperature sensing module senses the voltage signal, and the voltage signal is used as a path of temperature sampling signal obtained by carrying out temperature sampling on a temperature measuring position of a winding of a motor controlled by the frequency converter.
In some embodiments, the differential amplification module comprises: the first resistor module, the second resistor module, the third resistor module, the fourth resistor module, the first capacitor module, the second capacitor module and the first operational amplifier module; the common end of the first voltage dividing module and the second voltage dividing module is connected to the inverting input end of the first operational amplifier module after passing through the first resistor module; the inverting input end of the first operational amplifier module is connected to the output end of the first operational amplifier module after passing through the fourth resistor module and the second capacitor module which are connected in parallel; the common end of the third voltage dividing module and the temperature sensing module is connected to the non-inverting input end of the first operational amplifier module after passing through the second resistor module; the non-inverting input end of the first operational amplifier module is connected to the output end of the first operational amplifier module after passing through the third resistor module and the first capacitor module which are connected in parallel; the output end of the first operational amplifier module is used as the output end of the differential amplifying module and is used for outputting one path of voltage signal as one path of temperature sampling signal obtained by performing temperature sampling on one temperature measuring position of a winding of a motor controlled by the frequency converter.
In some embodiments, each of the two or more temperature sampling modules further comprises: a first filtering module; the output end of the differential amplification module is grounded after passing through the first filtering module; the output side of the first filtering module is used as the output end of each of the more than two temperature sampling modules and is used for outputting one path of voltage signal as one path of temperature sampling signal obtained by performing temperature sampling on one temperature measuring position of a winding of a motor controlled by the frequency converter.
In some embodiments, the temperature selection module comprises: a data selector and a second filtering module; the data selector is used for selecting one path of temperature sampling signals from more than two paths of temperature sampling signals under the control of the current round of the motor controller; the second filtering module is configured to filter one path of temperature sampling signals selected from more than two paths of temperature sampling signals, and output the filtered one path of temperature sampling signals as one path of temperature sampling signals obtained by current selection.
In some embodiments, further comprising: an over-temperature protection module; the over-temperature protection module is used for performing over-temperature detection based on one path of temperature sampling signals obtained through current selection and outputting an over-temperature detection result; the over-temperature detection result comprises: over-temperature or not over-temperature; the motor controller is also used for controlling the frequency converter to stop or continue to operate according to the over-temperature detection result; if the over-temperature detection result is over-temperature, controlling the frequency converter to stop; and if the over-temperature detection result is that the over-temperature is not over-temperature, controlling the frequency converter to continue to operate.
In some embodiments, the over-temperature protection module comprises: the system comprises a fourth voltage division module, a fifth voltage division module, a second operational amplifier module and a third filtering module; the temperature selection module selects and outputs a current selected temperature sampling signal, and inputs the current selected temperature sampling signal to the inverting input end of the second operational amplifier module; the power supply voltage is grounded after passing through the fourth voltage dividing module and the fifth voltage dividing module; the common end of the fourth voltage dividing module and the fifth voltage dividing module is connected to the non-inverting input end of the second operational amplifier module; the output end of the second operational amplifier module is grounded after passing through the third filtering module; the output side of the third filtering module is used as the output side of the over-temperature protection module and is used for outputting an over-temperature detection result; the second operational amplifier module is configured to compare voltages output by the common ends of the fourth voltage dividing module and the fifth voltage dividing module based on the current selected one-way temperature sampling signal, so as to obtain a comparison result, and take the comparison result as the over-temperature detection result, and output the over-temperature detection result from the output end of the over-temperature protection module.
In some embodiments, further comprising: a temperature display module; the motor controller is further used for sending a display instruction based on one path of temperature sampling signal obtained by current selection; the temperature display module is used for displaying at least one path of temperature sampling signal obtained by current selection based on the display instruction.
In accordance with another aspect of the present invention, there is provided a frequency converter comprising: the temperature detection device of the frequency converter is described above.
In accordance with another aspect of the present invention, there is provided a control method of a temperature detecting device of a frequency converter, including: after the frequency converter is started, under the condition that the motor runs, determining whether a temperature sensing module in the temperature sampling module is disconnected; if the temperature sensing module in the temperature sampling module is determined to be disconnected, controlling the frequency converter to stop; if the temperature sensing module in the temperature sampling module is not disconnected, controlling the temperature selecting module so that the temperature selecting module selects one path of temperature sampling signals from more than two paths of temperature sampling signals to output under the control of the current round, and the one path of temperature sampling signals are used as one path of temperature sampling signals obtained through current selection; and performing new current round of control on the temperature selection module based on the current selected one-way temperature sampling signal, so that the temperature selection module performs polling selection on more than two ways of temperature sampling signals to select another way of temperature sampling signals to output, and the other way of temperature sampling signals are used as one way of temperature sampling signals obtained by the new current selection, so as to perform polling control; and/or, if the over-temperature detection result output by the over-temperature protection module is received under the condition that the temperature detection device of the frequency converter further comprises the over-temperature protection module, controlling the frequency converter to stop or continue to operate according to the over-temperature detection result; if the over-temperature detection result is over-temperature, controlling the frequency converter to stop; and if the over-temperature detection result is that the over-temperature is not over-temperature, controlling the frequency converter to continue to operate.
Therefore, according to the scheme of the invention, through setting more than two temperature sampling circuits and more than two temperature signal selection circuits, each of the more than two temperature sampling circuits is utilized to sample the temperature of the equipment to be measured (such as a motor winding) to obtain corresponding temperature sampling signals; selecting one temperature signal by using more than two temperature signal selection circuits under the control of a controller (such as a motor controller) so as to control based on the one temperature signal; therefore, the sampling pressure of the DSP chip is reduced by combining and outputting more than two paths of temperature sampling signals of the frequency converter to one sampling port of the DSP chip. Meanwhile, over-temperature protection is carried out according to one path of temperature signals obtained through selection, the problem that timely protection cannot be carried out due to abnormal temperature sampling is solved, and safety is higher.
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 scheme of the invention is further described in detail through the drawings and the embodiments.
Drawings
FIG. 1 is a schematic diagram illustrating an embodiment of a temperature detecting device of a frequency converter according to the present invention;
FIG. 2 is a schematic diagram illustrating an embodiment of a multi-channel temperature sampling and over-temperature protection device for a frequency converter according to the present invention;
FIG. 3 is a schematic diagram illustrating an embodiment of a single-path PT100 temperature sampling circuit in a multi-path temperature sampling and over-temperature protection device of a frequency converter according to the present invention;
FIG. 4 is a schematic diagram illustrating an embodiment of a multi-channel temperature selection circuit in a multi-channel temperature sampling and over-temperature protection device according to the present invention;
FIG. 5 is a schematic diagram illustrating an embodiment of an over-temperature protection circuit in a multi-channel temperature sampling and over-temperature protection device according to the present invention;
FIG. 6 is a flow chart of a method for multi-channel temperature sampling and over-temperature protection according to an embodiment of the present invention;
fig. 7 is a flowchart illustrating a control method of a temperature detecting device of a frequency converter according to an embodiment of the 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 specific embodiments of the present invention and corresponding drawings. It will be apparent that the described embodiments are only some, but not all, embodiments of the invention. All other embodiments, which can be made by those skilled in the art based on the embodiments of the invention without making any inventive effort, are intended to be within the scope of the invention.
According to an embodiment of the invention, a temperature detection device of a frequency converter is provided. Referring to fig. 1, a schematic diagram of an embodiment of the apparatus of the present invention is shown. The temperature detection device of the frequency converter may include: the system comprises a temperature sampling module, a temperature selecting module and a motor controller; the number of the temperature sampling modules is more than two.
Each of the two or more temperature sampling modules is used for sampling the temperature of one temperature measuring position of a winding of a motor controlled by the frequency converter to obtain one path of temperature sampling signals; through more than two temperature sampling modules, more than two paths of temperature sampling signals can be obtained.
The temperature selection module is used for selecting one path of temperature sampling signals from more than two paths of temperature sampling signals to output under the control of the current round of the motor controller, and the one path of temperature sampling signals are used as one path of temperature sampling signals obtained through current selection.
And the motor controller is used for carrying out new current round control on the temperature selection module based on one path of temperature sampling signals obtained by current selection so as to enable the temperature selection module to carry out polling selection on more than two paths of temperature sampling signals to select the other path of temperature sampling signals to output, and the other path of temperature sampling signals are used as one path of temperature sampling signals obtained by new current selection so as to carry out polling control.
Fig. 2 is a schematic structural diagram of an embodiment of a multi-channel temperature sampling and over-temperature protection device for a frequency converter according to the present invention. The device for multi-channel temperature sampling and over-temperature protection of the frequency converter shown in fig. 2 mainly comprises various modules inside the frequency converter and an external magnetic suspension motor (such as a motor M). Each module in the frequency converter comprises a rectifier diode D 1 ～D 6 Bus capacitor C d Discharge resistor R d IGBT module T inverts 1 ～T 6 The multi-channel temperature sampling and over-temperature protection device and the control system (such as a motor controller can adopt a DSP chip); rectifier diode D 1 ～D 6 A rectifying circuit is formed; inversion IGBT module T 1 ～T 6 An inverter circuit is formed. Multichannel temperature sampling and overtemperature protection device includes: a temperature sampling circuit (specifically, a multi-path temperature sampling circuit), a multi-path temperature selecting and outputting circuit. Discharge resistor R d For discharging the frequency converter when the motor is stopped.
In the example shown in FIG. 2, three-phase (such as A phase, B phase and C phase) alternating current outputted by an alternating current power supply passes through a rectifying circuit and a bus capacitor C d Discharge resistor R d And after the inverter circuit, outputting an alternating current power supply to the motor M. Temperature samplingThe circuit utilizes a multi-path thermistor (such as a multi-path PT100 thermistor) to sample and process the temperatures of the multi-path windings of the motor M, obtains multi-path temperature signals and outputs the multi-path temperature signals to the multi-path temperature selection circuit. The multi-path temperature selection circuit is used for carrying out multi-path temperature selection on the input multi-path temperature signals and then outputting one path of temperature signals so as to convert the multi-path temperature signals into one path of temperature signals; the motor controller outputs temperature display information to the temperature display circuit, and the motor controller outputs control signals to the multi-path temperature selection circuit. Specifically, the motor controller directly polls according to time, for example, the controller starts to output a control signal 000 to control the output of a first path of temperature signal, outputs 001 to control the output of a second path of temperature signal after 1ms, outputs 010 after 1ms, and so on; if there are eight temperature signals in total, the motor controller will output until 111, and then after 1ms, it will change back to 000 again to continue to control the first output.
The multichannel temperature sampling and over-temperature protection device is used for collecting temperature signals using the PT100 thermistor, for example, collecting temperatures of multiple motor windings, and concentrating the multiple temperature signals into one channel through the multiple temperature selection circuits, and outputting the one channel of signals to the main control system (such as a motor controller) for data collection.
The scheme of the invention provides a multichannel temperature sampling and over-temperature protection device of a frequency converter, which can combine and output multichannel temperature sampling signals of the frequency converter to a DSP chip according to actual conditions, reduce the sampling pressure of the DSP chip and solve the problem that multichannel temperature of the frequency converter cannot be monitored due to shortage of sampling ports of the DSP chip. The scheme is simple and reliable, improves the application performance of the frequency converter, and can meet the requirements of most application occasions.
In some embodiments, each of the two or more temperature sampling modules comprises: a first voltage dividing module, a second voltage dividing module, a third voltage dividing module, a temperature sensing module, and a differential amplifying module, wherein the first voltage dividing module is a resistor R 1 A second voltage dividing module such asResistor R 2 A third voltage dividing module such as resistor R 3 Temperature sensing modules such as resistors R PT100 Differential amplifying modules, e.g. chips U 1 And its peripheral resistance and capacitance.
The temperature sensing module is arranged at one temperature measuring position of the winding of the motor controlled by the frequency converter and is used for sensing the temperature of the one temperature measuring position of the winding of the motor controlled by the frequency converter, and the temperature sensing module senses a voltage signal under the condition that the temperature of the one temperature measuring position of the winding of the motor controlled by the frequency converter changes.
The power supply voltage is grounded after passing through the first voltage dividing module and the second voltage dividing module; the power supply voltage is grounded after passing through the third voltage dividing module and the temperature sensing module; the common end of the first voltage dividing module and the second voltage dividing module is connected to the inverting input end of the differential amplifying module; and the common end of the third voltage dividing module and the temperature sensing module is connected to the non-inverting input end of the differential amplifying module. The first voltage dividing module, the second voltage dividing module, the third voltage dividing module and the temperature sensing module form a bridge structure; under the condition that the temperature sensing module senses a voltage signal, the bridge structure generates a voltage difference, namely, a voltage difference generated between an inverting input end of the differential amplifying module and a non-inverting input end of the differential amplifying module. The differential amplification module is used for outputting a path of voltage signal after differential amplification is carried out on the voltage difference input by the inverting input end of the differential amplification module and the non-inverting input end of the differential amplification module under the condition that the temperature sensing module senses the voltage signal, and the voltage signal is used as a path of temperature sampling signal obtained by carrying out temperature sampling on a temperature measuring position of a winding of a motor controlled by the frequency converter.
Fig. 3 is a schematic structural diagram of an embodiment of a single-path PT100 temperature sampling circuit in a multi-path temperature sampling and over-temperature protection device of a frequency converter according to the present invention. The single-path PT100 temperature sampling circuit shown in fig. 3 mainly includes: the temperature sampling circuit converts the resistance value obtained by converting the temperature of the single-way winding of the motor into a corresponding voltage signal.
In some embodiments, the differential amplification module comprises: first resistor module, second resistor module, third resistor module, fourth resistor module, first capacitor module, second capacitor module and first operational amplifier module, the first resistor module is resistor R 4 A second resistor module such as resistor R 5 Third resistor modules, e.g. resistor R 6 Fourth resistor modules, e.g. resistor R 7 First capacitance module, e.g. capacitance C 2 A second capacitance module such as a capacitor C 3 And a first operational amplifier module such as a chip U 1 。
The common end of the first voltage dividing module and the second voltage dividing module is connected to the inverting input end of the first operational amplifier module after passing through the first resistor module; and the inverting input end of the first operational amplifier module is connected to the output end of the first operational amplifier module after passing through the fourth resistor module and the second capacitor module which are connected in parallel. The common end of the third voltage dividing module and the temperature sensing module is connected to the non-inverting input end of the first operational amplifier module after passing through the second resistor module; the non-inverting input end of the first operational amplifier module is connected to the output end of the first operational amplifier module after passing through the third resistor module and the first capacitor module which are connected in parallel; the output end of the first operational amplifier module is used as the output end of the differential amplifying module and is used for outputting one path of voltage signal as one path of temperature sampling signal obtained by performing temperature sampling on one temperature measuring position of a winding of a motor controlled by the frequency converter.
Specifically, in the single-path PT100 temperature sampling circuit as shown in FIG. 3, the voltage V d Through resistor R 1 And resistance R 2 Rear ground; voltage V d And also via a resistor R 3 And resistance R PT100 And the rear is grounded. Resistor R 1 And resistance R 2 Via capacitor C 1 Rear ground; resistor R 1 And resistance R 2 And also via the rear resistor R 4 Then, connect to the chip U 1 Is provided. Resistor R 3 And resistance R PT100 Is a common terminal of the post-warp resistor R 5 Then, connect to the chip U 1 Is provided. Chip U 1 Is connected in parallel with a resistor R 7 And capacitor C 3 Then, connect to the chip U 1 Is provided. Chip U 1 Through parallel resistors R 6 And capacitor C 2 And then, grounding.
In some embodiments, each of the two or more temperature sampling modules further comprises: a first filter module, such as a fifth resistor module, such as resistor R, and a third capacitor module 8 And a third capacitance module such as capacitance C 4 。
The output end of the differential amplification module is grounded after passing through the first filtering module, specifically, is grounded after passing through the fifth resistance module and the third capacitance module; the output side of the first filtering module, specifically, the common end of the fifth resistor module and the third capacitor module, is used as each of the two or more temperature sampling modules, and is used for outputting a path of voltage signal as a path of temperature sampling signal obtained by performing temperature sampling on a temperature measuring position of a winding of a motor controlled by the frequency converter.
Specifically, in the single-path PT100 temperature sampling circuit shown in fig. 3, the chip U 1 Through resistor R 8 And capacitor C 4 Then, grounding; resistor R 8 And capacitor C 4 Is connected to terminal X 0 。
In the single-path PT100 temperature sampling circuit as shown in FIG. 3, the resistor R PT100 The temperature of the thermistor PT100 corresponds to a resistance value of 100 omega, and the higher the temperature is, the larger the resistance value is. Resistor R 1 Resistance R 2 Resistance R 3 Resistance R 4 Resistance R 5 Resistance R 6 Resistance R 7 Resistance R 8 Is a resistor with a fixed resistance value. Capacitor C 1 Capacitance C 2 Capacitance C 3 Capacitance C 4 Is a filter capacitor. Chip U 1 Is an operational amplifier. Voltage V d Is the supply voltage. Voltage V 1 Is a resistor R 1 And resistance R 2 Voltage between them. Voltage V 2 Is a resistor R 3 And resistance R 4 Voltage between them. Voltage V a And voltage V b Is a chip U 1 Is provided, the voltage at the two input terminals of (a) is provided. Voltage V c Is a chip U 1 Is provided. The winding to be measured is formed by winding a plurality of coils, and the thermistor is buried in the coils in the winding process or is attached to the surface of the coils, in particular to the temperature to be measured.
In the example shown in FIG. 3, the resistor R 1 Resistance R 2 Resistance R 3 Resistance R PT100 Form a bridge structure, and when the circuit works normally, the resistor R PT100 The resistance value of (2) changes along with the temperature, the balance of the bridge is broken, and weak voltage difference is formed at two ends of the bridge. The voltage difference is amplified by a differential amplifying circuit and then RC filtered (e.g. by resistor R 8 And capacitor C 4 The RC filter circuit configured performs RC filtering) and then outputs the result. The differential circuit processing is adopted, so that the sampling is more accurate. The calculation formula of the single-path PT100 temperature sampling circuit is as follows:
；
；
。
in the present circuit: r is R 4 =R 5 ，R 6 =R 7 。
And finally, the voltage V is deduced according to the characteristics of the operational amplifier c Is calculated according to the formula:
。
in the scheme of the invention, the sampling circuit adopts a bridge structure and a differential amplifying circuit, and weak voltage signals can be accurately acquired and amplified through the bridge structure; when the circuit works normally, the resistance value of the thermistor changes along with the temperature, the balance of the bridge is broken, weak voltage difference is formed at two ends of the bridge, and the voltage difference is amplified by the differential amplifying circuit and then output after RC filtering; compared with the related scheme, the voltage signal is obtained by using a voltage dividing circuit formed by a thermistor and a common resistor, and the voltage signal has the characteristics of high precision and good stability.
In some embodiments, the temperature selection module comprises: a data selector such as an eighth data selector, and a second filter module such as a resistor R 9 And capacitor C 5 。
The data selector is used for selecting one path of temperature sampling signals from more than two paths of temperature sampling signals under the control of the current round of the motor controller.
The second filtering module is configured to filter one path of temperature sampling signals selected from more than two paths of temperature sampling signals, and output the filtered one path of temperature sampling signals as one path of temperature sampling signals obtained by current selection.
Fig. 4 is a schematic diagram of a multi-channel temperature selecting circuit in the multi-channel temperature sampling and over-temperature protection device according to an embodiment of the invention. In the multi-path temperature selection circuit shown in FIG. 4, the chip U 2 For eight data selector, chip U 2 Terminal X of (2) 0 -terminal X 7 For data input, chip U 2 Terminal X of (1) is a data output terminal, chip U 2 Terminal a, chip U of (a) 2 Terminal B, chip U 2 Terminal C of (a) is an address terminal, and chip U 2 Terminal INH of (a) is an enable terminal; when chip U 2 When the terminal INH of (1) is low level, the chip U 2 The address terminal CBA of (1) correspondingly outputs X from 000 to 111 0 ～X 7 . Resistor R 9 Resistance, capacitance C, of fixed resistance 5 Capacitance C 6 For filtering capacitance, chip U 3 Is a DSP chip of a master control system. The output end (such as terminal X) of the single-path PT100 temperature sampling circuit shown in FIG. 3 0 ) And the temperature sampling circuit is connected to the X0 end of the data selector, and the like, and at most eight paths of single-path PT100 temperature sampling circuits can be connected simultaneously. Then control chip U through master control system 2 The address terminal CBA and the enable terminal INH of the chip U can poll and sample all temperature signals according to the programmed time and the temperature signals are stored in the chip U 2 And (3) carrying out single-path output at the X end of the device. After the frequency converter is electrified, the motor controller is electrified, the enabling end outputs high level, and the temperature signal of the winding is not received; when the motor is started, the enabling end outputs low level, the address end outputs CBA corresponding to 000, and receives X0 paths of signals; after 1ms, the address side goes to 001, receiving X1 signals, and the polling cycle. The output temperature signal TEMP is output to the main control DSP chip on one hand; on the other hand, to a fault detection circuit (e.g., an over-temperature protection circuit). The DSP chip of the main control system outputs control signals, so that the multi-path temperature selection circuit can poll a plurality of single-path temperature samples, at most, eight temperature sampling circuit sets can be combined into one path for output, and the output temperature signals can be given to the main control system on one hand and can be given to a fault detection circuit (such as an over-temperature protection circuit) on the other hand. The multi-path temperature selection circuit can combine the multi-path temperature signals into one path for polling output, so that sampling ports of the DSP chip are saved.
In the scheme of the invention, a data selector is adopted for multi-path temperature selection, the output end of a multi-path sampling circuit is connected to the input end of the data selector, and a control signal is sent through a DSP chip, so that multi-path temperature signals can be controlled to be polled and output at one output end; the output end of the single-path temperature sampling circuit is connected with the input end of the data selector, and the like, and at most eight paths of temperature sampling can be simultaneously connected; then through the address end and the enabling end controlled by the main control system, all temperature signals can be polled and sampled according to the program set time, and single-way output is carried out at the output end; the circuit can not only save sampling ports of the DSP chip, but also collect data of each path of sampling points to the DSP chip.
In the scheme of the invention, the multipath temperature signals are integrated into one path of signals and fed back to one sampling port of the DSP chip, so that the main control of the power supply system of the motor can sample more sampling points of the frequency converter; the multi-channel temperature sampling can be detected simultaneously, the requirement of a sampling interface is reduced, and the cost of the frequency converter is effectively reduced, so that the problem that the multi-channel temperature of the frequency converter cannot be monitored due to the shortage of the sampling ports of the DSP chip is solved.
In some embodiments, the temperature detection device of the frequency converter according to the present invention further includes: and an over-temperature protection module.
The over-temperature protection module is used for performing over-temperature detection based on one path of temperature sampling signals obtained through current selection and outputting an over-temperature detection result; the over-temperature detection result comprises: over-temperature or not.
The motor controller is also used for controlling the frequency converter to stop or continue to operate according to the over-temperature detection result; if the over-temperature detection result is over-temperature, controlling the frequency converter to stop; and if the over-temperature detection result is that the over-temperature is not over-temperature, controlling the frequency converter to continue to operate.
Specifically, in the example shown in fig. 2, the multi-channel temperature sampling and over-temperature protection device includes: the temperature sampling circuit (specifically, a multi-path temperature sampling circuit), a multi-path temperature selecting and outputting circuit and a fault detecting circuit (such as an over-temperature protection circuit). The multi-path temperature selection circuit is used for carrying out multi-path temperature selection on the input multi-path temperature signals and then outputting one path of temperature signals so as to convert the multi-path temperature signals into one path of temperature signals; the over-temperature protection circuit judges whether over-temperature occurs based on the one-path temperature signal to perform over-temperature protection, and outputs a fault signal to a motor controller when an over-temperature fault exists, and the motor controller outputs a shutdown signal to control elements (such as an inversion IGBT module T) in each module inside the frequency converter 1 ～T 6 ) The method comprises the steps of carrying out a first treatment on the surface of the The motor controller outputs temperature display information to the temperature display circuit, and the motor controller outputs control signals to the multi-path temperature selection circuit.
The multichannel temperature sampling and over-temperature protection device is used for collecting temperature signals using the PT100 thermistor, such as collecting the temperatures of multiple motor windings, and concentrating the multiple temperature signals into one channel through the multiple temperature selection circuits. On one hand, the signal is output to a main control system (such as a motor controller) for data collection, and on the other hand, the signal is subjected to over-temperature judgment, if the temperature is abnormal, a fault signal is output to the main control system, the main control system controls the frequency converter to stop, and the motor stops, so that the motor is protected from being burnt. In the scheme of the invention, the over-temperature detection and fault processing can be carried out on the temperature signal, and the hardware protection can be implemented on the motor when the temperature is over-temperature, so that the reliability of the frequency converter is effectively improved.
According to the scheme, the multichannel temperature sampling signals of the frequency converter can be combined and output to the DSP chip according to actual conditions, so that the sampling pressure of the DSP chip is reduced, and the problem that the multichannel temperature of the frequency converter cannot be monitored due to the shortage of sampling ports of the DSP chip is solved; meanwhile, over-temperature protection is provided, the problem that timely protection cannot be achieved due to abnormal temperature sampling is solved, and safety is higher.
In some embodiments, the over-temperature protection module comprises: a fourth voltage dividing module, a fifth voltage dividing module, a second operational amplifier module and a third filter module, wherein the fourth voltage dividing module is like a resistor R 11 Fifth voltage dividing module resistor R 12 Second operational amplifier module, e.g. chip U 4 And a third filter module such as resistor R 13 And capacitor C 7 。
The temperature selection module selects and outputs a current selected temperature sampling signal, and inputs the current selected temperature sampling signal to the inverting input end of the second operational amplifier module; the power supply voltage is grounded after passing through the fourth voltage dividing module and the fifth voltage dividing module; the common end of the fourth voltage dividing module and the fifth voltage dividing module is connected to the non-inverting input end of the second operational amplifier module; the output end of the second operational amplifier module is grounded after passing through the third filtering module; and the output side of the third filtering module is used as the output side of the over-temperature protection module and is used for outputting an over-temperature detection result. The second operational amplifier module is configured to compare voltages output by the common ends of the fourth voltage dividing module and the fifth voltage dividing module based on the current selected one-way temperature sampling signal, so as to obtain a comparison result, and take the comparison result as the over-temperature detection result, and output the over-temperature detection result from the output end of the over-temperature protection module.
Specifically, fig. 5 is a schematic structural diagram of an embodiment of an over-temperature protection circuit in the multi-channel temperature sampling and over-temperature protection device according to the present invention. In a frequency converter fault detection circuit such as an over-temperature protection circuit as shown in fig. 5, a resistor R 10 Resistance R 11 Resistance R 12 Resistance R 13 Resistance, capacitance C, of fixed resistance 7 For filtering capacitance, chip U 4 Is an operational amplifier. Voltage V 3 Is a chip U 4 Voltage V of positive input terminal 4 Is the voltage V d Through resistance R 11 And voltage R 12 The divided voltage. Resistor R 11 And voltage R 12 Is connected to the operational amplifier U 4 Is provided with a non-inverting input terminal; temperature signal TEMP passes through resistor R 10 Then input to an operational amplifier U 4 And an operational amplifier U 4 Voltage V input by non-inverting input terminal of (C) 4 Comparing if the preset voltage (i.e. voltage V 4 ) The trigger fault TZ signal is fed back to the DSP chip. Operational amplifier U 4 Through resistor R 13 And capacitor C 7 Rear ground; resistor R 13 And capacitor C 7 Is connected to the TZ terminal. The calculation formula of the fault detection circuit is as follows:
。
if the voltage V 3 < voltage V 4 And if the temperature is normal, the TZ terminal outputs a high level, and the frequency converter operates normally. If the voltage V 3 Voltage V or more 4 And if the temperature is abnormal, the TZ terminal outputs a low level, the frequency converter is stopped, and the motor is stopped. Through the over-temperature protection circuit, when the temperature represented by the temperature signal TEMP exceeds the temperatureAnd outputting a fault signal to the main control system when the protection value is exceeded.
In some embodiments, the temperature detection device of the frequency converter according to the present invention further includes: and a temperature display module.
The motor controller is also used for sending a display instruction based on the current selected one-path temperature sampling signal.
The temperature display module is used for displaying at least one path of temperature sampling signal obtained by current selection based on the display instruction.
Specifically, in the example shown in fig. 2, each module inside the frequency converter includes a rectifying diode D 1 ～D 6 Bus capacitor C d Discharge resistor R d IGBT module T inverts 1 ～T 6 The temperature sensor comprises a multichannel temperature sampling and over-temperature protection device, a control system (such as a motor controller can adopt a DSP chip) and a display (such as a temperature display circuit); rectifier diode D 1 ～D 6 And forming a rectifying circuit.
By adopting the technical scheme, through setting more than two temperature sampling circuits and more than two temperature signal selection circuits, each of the more than two temperature sampling circuits is utilized to sample the temperature of the equipment to be measured (such as a motor winding) to obtain corresponding temperature sampling signals; selecting one temperature signal by using more than two temperature signal selection circuits under the control of a controller (such as a motor controller) so as to control based on the one temperature signal; therefore, the sampling pressure of the DSP chip is reduced by combining and outputting more than two paths of temperature sampling signals of the frequency converter to one sampling port of the DSP chip. Meanwhile, over-temperature protection is carried out according to one path of temperature signals obtained through selection, the problem that timely protection cannot be carried out due to abnormal temperature sampling is solved, and safety is higher.
According to an embodiment of the present invention, there is also provided a frequency converter corresponding to the temperature detecting device of the frequency converter. The frequency converter may include: the temperature detection device of the frequency converter is described above.
Since the processes and functions implemented by the frequency converter of the present embodiment basically correspond to the embodiments, principles and examples of the apparatus, the description of the present embodiment is not exhaustive, and reference may be made to the related descriptions in the foregoing embodiments, which are not repeated herein.
By adopting the technical scheme, through setting more than two temperature sampling circuits and more than two temperature signal selection circuits, each of the more than two temperature sampling circuits is utilized to sample the temperature of the equipment to be measured (such as a motor winding) to obtain corresponding temperature sampling signals; and more than two paths of temperature signal selection circuits are utilized, one path of temperature signal is selected under the control of a controller (such as a motor controller) so as to control based on the one path of temperature signal, and multiple paths of temperature sampling can be detected simultaneously, so that the requirement of a sampling interface is reduced, and the cost of the frequency converter is effectively reduced.
According to an embodiment of the present invention, there is further provided a control method of a temperature detecting device of a frequency converter corresponding to the frequency converter, as shown in fig. 7, which is a schematic flow chart of an embodiment of the method of the present invention. The control method of the temperature detection device of the frequency converter may include: step S110 to step S150.
At step S110, it is determined whether a temperature sensing module in the temperature sampling module is disconnected in a case where the motor is operated after the inverter is started.
At step S120, if it is determined that the temperature sensing module in the temperature sampling module is turned off, the frequency converter is controlled to stop.
At step S130, if it is determined that the temperature sensing module in the temperature sampling module is not disconnected, the temperature selecting module is controlled so that the temperature selecting module selects one temperature sampling signal from more than two temperature sampling signals to output under the control of the current round, and the one temperature sampling signal is used as the one temperature sampling signal obtained by the current selection. Further, step S140 and/or step S150 are/is performed.
At step S140, based on the one-way temperature sampling signal obtained by the current selection, a new current round of control is performed on the temperature selection module, so that the temperature selection module performs polling selection on more than two ways of temperature sampling signals to select another way of temperature sampling signals to output, and the other way of temperature sampling signals are used as the one way of temperature sampling signal obtained by the new current selection, so as to perform polling control.
At step S150, if an over-temperature detection result output by the over-temperature protection module is received under the condition that the temperature detection device of the frequency converter further includes the over-temperature protection module, controlling the frequency converter to stop or continue to operate according to the over-temperature detection result; if the over-temperature detection result is over-temperature, controlling the frequency converter to stop; and if the over-temperature detection result is that the over-temperature is not over-temperature, controlling the frequency converter to continue to operate.
Specifically, fig. 6 is a flow chart of an embodiment of a method for multi-channel temperature sampling and over-temperature protection according to the present invention. The method for multi-channel temperature sampling and over-temperature protection as shown in fig. 6 comprises the following steps:
step 1, after a frequency converter is started, the frequency converter operates to enable a motor to operate; meanwhile, it is judged whether the PT100 thermistor is turned off: if the PT100 thermistor is detected to be disconnected, the frequency converter is in fault and stops in time; if the PT100 thermistor is detected to be connected normally, the step 2 is executed. Wherein, when the motor is running, if the DSP chip receives a 3.3V voltage signal, the thermistor is turned off. Because only two conditions can lead the DSP chip to receive 3.3V voltage, firstly, the winding temperature reaches more than 177 ℃ and the PT100 becomes more than 168 omega, but the motor just runs, and obviously, the temperature cannot exist; and secondly, the thermistor is disconnected, and the resistance becomes infinite, so that the thermistor can be judged to be disconnected.
Step 2, under the condition that normal connection of PT100 thermistors is detected, the plurality of PT100 thermistors measure the temperature of a motor winding, after passing through a multi-path temperature sampling circuit and a multi-path temperature selecting circuit, a temperature signal enters a fault detection device, the fault detection circuit judges whether the temperature is over-temperature, if the temperature is over-temperature, a fault signal is sent out, a frequency converter is stopped, and the motor stops rotating; and if the temperature is normal, continuing to detect, namely returning to the step 2.
The scheme of the invention can be used in parallel at different types of environment temperatures. The scheme of the invention is not limited to be used on a frequency converter, and can be also used on any circuit with a temperature sampling module. For example: the scheme can be used for measuring the temperature of the winding, the temperature of the IGBT and the temperature of the bus capacitor; they all differ in ambient temperature but can all be measured simultaneously. The scheme of the invention is not limited to PT100 thermistor, but can be replaced by other types of NTC resistors.
Since the processing and the functions implemented by the method of the present embodiment basically correspond to the embodiments, principles and examples of the frequency converter, the description of the present embodiment is not exhaustive, and reference may be made to the related descriptions in the foregoing embodiments, which are not repeated herein.
By adopting the technical scheme of the embodiment, through setting more than two temperature sampling circuits and more than two temperature signal selection circuits, each temperature sampling circuit in the more than two temperature sampling circuits is utilized to sample the temperature of the equipment to be measured (such as a motor winding) to obtain corresponding temperature sampling signals; by using more than two paths of temperature signal selection circuits, one path of temperature signal is selected under the control of a controller (such as a motor controller) so as to control based on the one path of temperature signal, the sampling pressure of a DSP chip is reduced, the problem that the multipath temperature of a frequency converter cannot be monitored due to the shortage of sampling ports of the DSP chip is solved, and the difficulty of multichannel temperature sampling is reduced.
In summary, it is readily understood by those skilled in the art that the above-described advantageous ways 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, but various modifications and variations can be made to the present invention by those skilled in the art. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention should be included in the scope of the claims of the present invention.

Claims (9)

1. A temperature detection device of a frequency converter, comprising: the system comprises a temperature sampling module, a temperature selecting module and a motor controller; the number of the temperature sampling modules is more than two; wherein,
each of the two or more temperature sampling modules is used for sampling the temperature of one temperature measuring position of a winding of the motor controlled by the frequency converter to obtain one path of temperature sampling signals; through more than two temperature sampling modules, more than two paths of temperature sampling signals can be obtained;
the temperature selection module is used for selecting one path of temperature sampling signals from more than two paths of temperature sampling signals to output under the control of the current round of the motor controller, and taking the one path of temperature sampling signals as one path of temperature sampling signals obtained by current selection; each of the two or more temperature sampling modules includes: the temperature sensing device comprises a first voltage dividing module, a second voltage dividing module, a third voltage dividing module, a temperature sensing module and a differential amplifying module; the temperature sensing module is arranged at one temperature measuring position of the winding of the motor controlled by the frequency converter and is used for sensing the temperature of the one temperature measuring position of the winding of the motor controlled by the frequency converter, and the temperature sensing module senses a voltage signal under the condition that the temperature of the one temperature measuring position of the winding of the motor controlled by the frequency converter changes; the power supply voltage is grounded after passing through the first voltage dividing module and the second voltage dividing module; the power supply voltage is grounded after passing through the third voltage dividing module and the temperature sensing module; the common end of the first voltage dividing module and the second voltage dividing module is connected to the inverting input end of the differential amplifying module; the common end of the third voltage dividing module and the temperature sensing module is connected to the non-inverting input end of the differential amplifying module; the first voltage dividing module, the second voltage dividing module, the third voltage dividing module and the temperature sensing module form a bridge structure; under the condition that the temperature sensing module senses a voltage signal, the bridge structure generates a voltage difference; the differential amplification module is used for outputting a path of voltage signal after differential amplification is carried out on the voltage difference input by the inverting input end of the differential amplification module and the non-inverting input end of the differential amplification module under the condition that the temperature sensing module senses the voltage signal, and the voltage signal is used as a path of temperature sampling signal obtained by carrying out temperature sampling on a temperature measuring position of a winding of a motor controlled by the frequency converter;
And the motor controller is used for carrying out new current round control on the temperature selection module based on one path of temperature sampling signals obtained by current selection so as to enable the temperature selection module to carry out polling selection on more than two paths of temperature sampling signals to select the other path of temperature sampling signals to output, and the other path of temperature sampling signals are used as one path of temperature sampling signals obtained by new current selection so as to carry out polling control.
2. The temperature detection device of a frequency converter according to claim 1, wherein the differential amplification module comprises: the first resistor module, the second resistor module, the third resistor module, the fourth resistor module, the first capacitor module, the second capacitor module and the first operational amplifier module; wherein,
the common end of the first voltage dividing module and the second voltage dividing module is connected to the inverting input end of the first operational amplifier module after passing through the first resistor module; the inverting input end of the first operational amplifier module is connected to the output end of the first operational amplifier module after passing through the fourth resistor module and the second capacitor module which are connected in parallel;
the common end of the third voltage dividing module and the temperature sensing module is connected to the non-inverting input end of the first operational amplifier module after passing through the second resistor module; the non-inverting input end of the first operational amplifier module is connected to the output end of the first operational amplifier module after passing through the third resistor module and the first capacitor module which are connected in parallel; the output end of the first operational amplifier module is used as the output end of the differential amplifying module and is used for outputting one path of voltage signal as one path of temperature sampling signal obtained by performing temperature sampling on one temperature measuring position of a winding of a motor controlled by the frequency converter.
3. The temperature detection device of a frequency converter according to claim 1, wherein each of the two or more temperature sampling modules further comprises: a first filtering module; wherein,
the output end of the differential amplification module is grounded after passing through the first filtering module; the output side of the first filtering module is used as the output end of each of the more than two temperature sampling modules and is used for outputting one path of voltage signal as one path of temperature sampling signal obtained by performing temperature sampling on one temperature measuring position of a winding of a motor controlled by the frequency converter.
4. The temperature detection device of a frequency converter according to claim 1, wherein the temperature selection module comprises: a data selector and a second filtering module; wherein,
the data selector is used for selecting one path of temperature sampling signals from more than two paths of temperature sampling signals under the control of the current round of the motor controller;
the second filtering module is configured to filter one path of temperature sampling signals selected from more than two paths of temperature sampling signals, and output the filtered one path of temperature sampling signals as one path of temperature sampling signals obtained by current selection.
5. The temperature detection device of a frequency converter according to any one of claims 1 to 4, further comprising: an over-temperature protection module; wherein,
the over-temperature protection module is used for detecting over-temperature based on one path of temperature sampling signal obtained by current selection and outputting an over-temperature detection result; the over-temperature detection result comprises: over-temperature or not over-temperature;
the motor controller is also used for controlling the frequency converter to stop or continue to operate according to the over-temperature detection result; if the over-temperature detection result is over-temperature, controlling the frequency converter to stop; and if the over-temperature detection result is that the over-temperature is not over-temperature, controlling the frequency converter to continue to operate.
6. The device according to claim 5, wherein the over-temperature protection module comprises: the system comprises a fourth voltage division module, a fifth voltage division module, a second operational amplifier module and a third filtering module; wherein,
one path of temperature sampling signal obtained by the current selection and output by the temperature selection module is input to the inverting input end of the second operational amplifier module; the power supply voltage is grounded after passing through the fourth voltage dividing module and the fifth voltage dividing module; the common end of the fourth voltage dividing module and the fifth voltage dividing module is connected to the non-inverting input end of the second operational amplifier module; the output end of the second operational amplifier module is grounded after passing through the third filtering module; the output side of the third filtering module is used as the output side of the over-temperature protection module and is used for outputting an over-temperature detection result;
The second operational amplifier module is configured to compare voltages output by the common ends of the fourth voltage dividing module and the fifth voltage dividing module based on the current selected one-way temperature sampling signal, so as to obtain a comparison result, and take the comparison result as the over-temperature detection result, and output the over-temperature detection result from the output end of the over-temperature protection module.
7. The temperature detection device of a frequency converter according to any one of claims 1 to 4, further comprising: a temperature display module; wherein,
the motor controller is also used for sending a display instruction based on one path of temperature sampling signal obtained by current selection;
the temperature display module is used for displaying at least one path of temperature sampling signal obtained by current selection based on the display instruction.
8. A frequency converter, comprising: a temperature detection device of a frequency converter according to any one of claims 1 to 7.
9. A control method of the temperature detection device of a frequency converter according to any one of claims 1 to 7, comprising:
after the frequency converter is started, under the condition that the motor runs, determining whether a temperature sensing module in the temperature sampling module is disconnected;
If the temperature sensing module in the temperature sampling module is determined to be disconnected, controlling the frequency converter to stop;
if the temperature sensing module in the temperature sampling module is not disconnected, controlling the temperature selecting module so that the temperature selecting module selects one path of temperature sampling signals from more than two paths of temperature sampling signals to output under the control of the current round, and the one path of temperature sampling signals are used as one path of temperature sampling signals obtained through current selection; the method comprises the steps of,
based on one path of temperature sampling signals obtained by current selection, carrying out new current round of control on the temperature selection module so as to enable the temperature selection module to carry out polling selection on more than two paths of temperature sampling signals, so as to select the other path of temperature sampling signals to output, and taking the other path of temperature sampling signals as one path of temperature sampling signals obtained by new current selection, thereby carrying out polling control; and/or the number of the groups of groups,
if the temperature detection device of the frequency converter further comprises an over-temperature protection module, if an over-temperature detection result output by the over-temperature protection module is received, controlling the frequency converter to stop or continue to operate according to the over-temperature detection result; if the over-temperature detection result is over-temperature, controlling the frequency converter to stop; and if the over-temperature detection result is that the over-temperature is not over-temperature, controlling the frequency converter to continue to operate.
CN202311541359.5A 2023-11-20 2023-11-20 Temperature detection device of frequency converter, control method thereof and frequency converter Pending CN117254747A (en)

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CN112799445A (en) * 2020-12-29 2021-05-14 珠海格力电器股份有限公司 Temperature processing system and method of frequency converter
CN215181618U (en) * 2021-07-29 2021-12-14 苏州伟创电气科技股份有限公司 Temperature sampling system, frequency converter and servo control system
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CN111174932A (en) * 2020-01-07 2020-05-19 上海电气集团股份有限公司 Temperature sampling detection system and method for multiple parallel IGBT modules
CN112799445A (en) * 2020-12-29 2021-05-14 珠海格力电器股份有限公司 Temperature processing system and method of frequency converter
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