CN219145368U - Optocoupler isolation voltage transmission circuit and frequency converter drive plate - Google Patents
Optocoupler isolation voltage transmission circuit and frequency converter drive plate Download PDFInfo
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- CN219145368U CN219145368U CN202223523438.7U CN202223523438U CN219145368U CN 219145368 U CN219145368 U CN 219145368U CN 202223523438 U CN202223523438 U CN 202223523438U CN 219145368 U CN219145368 U CN 219145368U
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Abstract
The embodiment of the utility model discloses an optical coupler isolation voltage transmission circuit and a frequency converter driving board. The optical coupling isolation voltage transmission circuit comprises an external power supply module voltage dividing module, a sawtooth wave module, a conversion module, an isolation module and a filtering module; the voltage dividing module is used for converting the power supply voltage input by the external power supply module into a preset voltage and sending the preset voltage to the conversion module; the sawtooth wave module is used for generating sawtooth wave voltage and sending the sawtooth wave voltage to the conversion module, and the conversion module is used for generating PWM voltage signals according to the received preset voltage and the sawtooth wave voltage and sending the PWM voltage signals to the isolation module; the output end of the conversion module is connected with the input end of the isolation module, and the isolation module is used for sending the PWM voltage signal to the filtering module; the output end of the isolation module is connected with the filtering module, and the filtering module is used for converting the PWM voltage signal into a motor rotating speed control signal. The circuit of the utility model not only meets the requirements of strong and weak electric isolation, but also can realize the isolated transmission of analog voltage signals and reduce the cost.
Description
Technical Field
The embodiment of the utility model relates to the technical field of power electronics, in particular to an optical coupling isolation voltage transmission circuit and a frequency converter driving plate.
Background
At present, a variable frequency driving board for a medium and small power section motor of a variable frequency air conditioner generally uses milliohm resistors to sample motor current, so that GND of a weak current micro control chip (Microcontroller Unit, MCU) of the driving board and GND of strong current are required to be commonly connected, and therefore a line controller or a main control board is required to control the variable frequency driving board in an isolation mode. In some occasions, the control of the wire controller to the motor adopts a 0-10V control mode, namely the wire controller outputs 0-10V of direct current analog quantity to the variable frequency drive board, the variable frequency drive board uses a specific isolation circuit to detect 0-10V from the wire controller and then transmits the detected 0-10V to the MCU chip of the variable frequency drive board, and finally the variable frequency drive board MCU controls the rotating speed of the motor according to a preset rotating speed demand meter.
At present, a linear isolation optocoupler is generally used in the market to build a voltage isolation transmission circuit so as to realize 1:1 isolation transmission of voltage signals. The linear isolation optocoupler has high cost because of the complex conversion circuit integrated inside, and the external operation amplifier chip is matched to realize the voltage isolation transmission function, as shown in fig. 1, so the overall cost is high.
Disclosure of Invention
The utility model provides an optocoupler isolation voltage transmission circuit and a frequency converter driving plate, which not only can meet the isolation requirements of strong and weak current, but also can realize the isolation transmission of analog voltage signals, and can reduce the cost compared with the prior art.
According to an aspect of the present utility model, there is provided an optocoupler isolated voltage transmission circuit, comprising: the device comprises an external power supply module, a voltage division module, a sawtooth wave module, a conversion module, an isolation module and a filtering module;
the input end of the voltage dividing module is connected with the external power supply module, and the output end of the voltage dividing module is connected with the first input end of the conversion module; the voltage dividing module is used for converting the power supply voltage input by the external power supply module into preset voltage and sending the preset voltage to the conversion module;
the sawtooth wave module is used for generating sawtooth wave voltage and sending the sawtooth wave voltage to the conversion module, and the output end of the sawtooth wave module is connected with the second input end of the conversion module;
the conversion module is used for generating PWM voltage signals according to the received preset voltage and the received sawtooth voltage and sending the PWM voltage signals to the isolation module; the output end of the conversion module is connected with the input end of the isolation module, and the isolation module is used for sending the PWM voltage signal to the filtering module;
the output end of the isolation module is connected with the filtering module, and the filtering module is used for converting the PWM voltage signal into a motor rotating speed control signal.
Optionally, the voltage dividing module includes: a dual diode, a first resistor, a first capacitor, a second resistor, a second capacitor, and a third capacitor;
the first end of the double diode is connected with the internal power supply end, the second end of the double diode is connected with the first end of the external power supply module, the second end of the external power supply module is connected with the first end of the first resistor, and the second end of the first resistor is connected with the third end of the double diode;
the second end of the first resistor is respectively connected with the second resistor, the second capacitor and the first end of the third capacitor, the second end of the second resistor, the second capacitor and the second end of the third capacitor are connected with the second end of the first capacitor and then grounded, the first end of the first capacitor is connected with the first end of the first resistor, and the first end of the third capacitor is used as the output end of the voltage dividing module.
Optionally, the sawtooth module includes: a third resistor, a fourth capacitor, a fourth resistor, a fifth resistor, a sixth resistor, a fifth capacitor, a seventh resistor, a sixth capacitor and a first comparator;
the first end of the third resistor is connected with the internal power supply end, the second end of the third resistor is connected with the first end of the first comparator, the first end of the fourth resistor and the first end of the fourth resistor are both connected with the second end of the third resistor, the second end of the fourth resistor and the second end of the fourth resistor are connected to the ground after being connected, the fifth resistor is connected between the first end and the output end of the first comparator, the second end of the first comparator serves as the output end of the sawtooth wave module, the output end of the first comparator is connected with the first end of the sixth resistor and the first end of the fifth capacitor respectively, the second end of the fifth resistor is grounded, the second end of the sixth resistor is connected with the second end of the seventh resistor, the first end of the seventh resistor is connected with the internal power supply end, the second end of the seventh resistor is connected with the first end of the sixth capacitor, the second end of the sixth resistor is connected with the first end of the sixth capacitor, and the second end of the sixth capacitor is connected with the first end of the sixth capacitor.
Optionally, the conversion module includes: a second comparator and a seventh capacitance;
the first end of the second comparator is connected with the output end of the voltage dividing module, the second end of the second comparator is connected with the output end of the sawtooth wave module, the third end of the second comparator is connected with the first end of the seventh capacitor, the first end of the seventh capacitor is connected with the internal power supply end, the second end of the seventh capacitor is grounded, the fourth end of the second comparator is grounded, and the output end of the second comparator is used as the output end of the conversion module.
Optionally, the isolation module includes an eighth resistor, a ninth resistor, and an optocoupler;
the first end of the eighth resistor is connected with the output end of the conversion module, the second end of the eighth resistor is connected with the second end of the ninth resistor, the first end of the ninth resistor is connected with the internal power supply end, the ninth resistor is connected between the first end and the second end of the optocoupler, the fourth end of the optocoupler is grounded, and the third end of the optocoupler is used as the output end of the isolation module.
Optionally, the filtering module includes a tenth resistor, an eleventh resistor, an eighth capacitor, and a ninth capacitor;
the first end of the tenth resistor is connected with the internal power supply end, the second end of the tenth resistor is connected with the first end of the eleventh resistor and then is connected with the output end of the isolation module, the second end of the eleventh resistor is respectively connected with the first end of the eighth capacitor and the first end of the ninth capacitor, the second end of the eighth capacitor is connected with the second end of the ninth capacitor and then is grounded, and the first end of the ninth capacitor is used as the output end of the filtering module.
Optionally, the first comparator is a voltage comparator, and the second comparator is a voltage comparator.
Optionally, the optocoupler isolation voltage transmission circuit further comprises a microcontroller module, wherein the microcontroller module is connected with the filtering module, and the microcontroller module is used for adjusting the rotating speed of the motor according to the motor rotating speed control signal.
Optionally, the input voltage of the external power supply module ranges from 0V to 10V.
According to another aspect of the present utility model, there is provided a frequency converter drive board comprising an optocoupler isolated voltage transmission circuit as described in any one of the above aspects.
The optocoupler isolation voltage transmission circuit of the embodiment of the utility model comprises: the device comprises an external power supply module, a voltage division module, a sawtooth wave module, a conversion module, an isolation module and a filtering module; the input end of the voltage dividing module is connected with the external power supply module, and the output end of the voltage dividing module is connected with the first input end of the conversion module; the voltage dividing module is used for converting the power supply voltage input by the external power supply module into a preset voltage and sending the preset voltage to the conversion module; the sawtooth wave module is used for generating sawtooth wave voltage and sending the sawtooth wave voltage to the conversion module, and the output end of the sawtooth wave module is connected with the second input end of the conversion module; the conversion module is used for generating PWM voltage signals according to the received preset voltage and sawtooth wave voltage and sending the PWM voltage signals to the isolation module; the output end of the conversion module is connected with the input end of the isolation module, and the isolation module is used for sending the PWM voltage signal to the filtering module; the output end of the isolation module is connected with the filtering module, and the filtering module is used for converting the PWM voltage signal into a motor rotating speed control signal. The embodiment of the utility model can construct a signal modulation circuit by using a common low-cost optocoupler, matching with a comparison device chip and a plurality of resistors and capacitors, thereby realizing the isolated transmission of voltage signals and solving the problems of high device cost in the prior art that the linear isolated optocoupler is adopted to realize the isolated transmission of the voltage signals; the isolation module in the embodiment of the utility model uses a common optocoupler, and the conversion module and the sawtooth wave module adopt low-cost devices such as a comparator to skillfully construct a circuit, thereby not only meeting the requirements of strong and weak electric isolation, but also realizing the isolated transmission of analog voltage signals and reducing the cost.
It should be understood that the description in this section is not intended to identify key or critical features of the embodiments of the utility model or to delineate the scope of the utility model. Other features of the present utility model will become apparent from the description that follows.
Drawings
In order to more clearly illustrate the technical solutions of the embodiments of the present utility model, the drawings required for the description of the embodiments will be briefly described below, and it is apparent that the drawings in the following description are only some embodiments of the present utility model, and other drawings may be obtained according to these drawings without inventive effort for a person skilled in the art.
FIG. 1 is a circuit schematic of an optocoupler isolated voltage transmission circuit of the prior art;
fig. 2 is a schematic structural diagram of an optical coupler isolation voltage transmission circuit according to an embodiment of the present utility model;
fig. 3 is a schematic circuit diagram of an optical coupler isolated voltage transmission circuit according to an embodiment of the present utility model;
fig. 4 is a waveform diagram of a second comparator in an optocoupler isolated voltage transmission circuit according to an embodiment of the present utility model;
fig. 5 is a schematic structural diagram of another optical coupler isolation voltage transmission circuit according to an embodiment of the present utility model;
fig. 6 is a schematic diagram of an operation process of an optocoupler isolation voltage transmission circuit according to an embodiment of the present utility model.
Detailed Description
In order that those skilled in the art will better understand the present utility model, a technical solution in the embodiments of the present utility model will be clearly and completely described below with reference to the accompanying drawings in which it is apparent that the described embodiments are only some embodiments of the present utility model, not all embodiments. All other embodiments, which can be made by those skilled in the art based on the embodiments of the present utility model without making any inventive effort, shall fall within the scope of the present utility model.
It should be noted that the terms "first," "second," and the like in the description and the claims of the present utility model and the above figures are used for distinguishing between similar objects and not necessarily for describing a particular sequential or chronological order. It is to be understood that the data so used may be interchanged where appropriate such that the embodiments of the utility model described herein may be implemented in sequences other than those illustrated or otherwise described herein. Furthermore, the terms "comprises," "comprising," and "having," and any variations thereof, are intended to cover a non-exclusive inclusion, such that a process, method, system, article, or apparatus that comprises a list of steps or elements is not necessarily limited to those steps or elements expressly listed but may include other steps or elements not expressly listed or inherent to such process, method, article, or apparatus.
Fig. 2 is a schematic structural diagram of an optocoupler isolation voltage transmission circuit according to an embodiment of the present utility model, and referring to fig. 2, an optocoupler isolation voltage transmission circuit according to an embodiment of the present utility model includes: the device comprises an external power supply module 10, a voltage division module 20, a sawtooth wave module 30, a conversion module 40, an isolation module 50 and a filtering module 60; the input end of the voltage division module 20 is connected with the external power supply module 10, and the output end of the voltage division module 20 is connected with the first input end of the conversion module 40; the voltage dividing module 20 is configured to convert a power supply voltage input by the external power supply module 10 into a preset voltage and send the preset voltage to the conversion module 40; the sawtooth wave module 30 is used for generating sawtooth wave voltage and sending the sawtooth wave voltage to the conversion module 40, and the output end of the sawtooth wave module 30 is connected with the second input end of the conversion module 40; the conversion module 40 is configured to generate a PWM voltage signal according to the received preset voltage and the sawtooth voltage, and send the PWM voltage signal to the isolation module 50; the output end of the conversion module 40 is connected with the input end of the isolation module 50, and the isolation module 50 is used for sending the PWM voltage signal to the filtering module 60; the output end of the isolation module 50 is connected with a filtering module 60, and the filtering module 60 is used for converting the PWM voltage signal into a motor rotation speed control signal.
Specifically, the voltage of the external power supply module 10 is derived from the power supply voltage externally input by the wire controller, the power supply voltage can be 0-10V, the power supply voltage is divided by the voltage division module 20 to obtain a preset voltage, the voltage range value of the preset voltage can be 0-4.31V, and then the preset voltage is input to the first input end of the conversion module 40; the sawtooth wave module 30 generates sawtooth wave voltage according to the difference of internal charge and discharge and sends the sawtooth wave voltage to the second input end of the conversion module 40, and the conversion module 40 outputs PWM voltage signals with adjustable duty ratio according to the preset voltage and the sawtooth wave voltage, so that the conversion from analog signals to digital signals is realized. The PWM voltage signal is sent to the isolation module 50, which can control the on/off of the isolation module 50, the isolation module 50 sends the PWM voltage signal to the filtering module 60, the filtering module 60 performs smooth filtering on the PWM voltage signal, and converts the PWM voltage signal into a motor rotation speed control voltage signal, so as to realize conversion of a digital signal (PWM voltage signal) into an analog signal (VSP voltage signal). Finally, the motor rotation speed control signal output by the filtering module 60 is sent to an analog signal detection port of the MCU chip, so that the rotation speed of the motor is controlled in real time.
The optocoupler isolation voltage transmission circuit of the embodiment of the utility model comprises: the device comprises an external power supply module, a voltage division module, a sawtooth wave module, a conversion module, an isolation module and a filtering module; the input end of the voltage dividing module is connected with the external power supply module, and the output end of the voltage dividing module is connected with the first input end of the conversion module; the voltage dividing module is used for converting the power supply voltage input by the external power supply module into a preset voltage and sending the preset voltage to the conversion module; the sawtooth wave module is used for generating sawtooth wave voltage and sending the sawtooth wave voltage to the conversion module, and the output end of the sawtooth wave module is connected with the second input end of the conversion module; the conversion module is used for generating PWM voltage signals according to the received preset voltage and sawtooth wave voltage and sending the PWM voltage signals to the isolation module; the output end of the conversion module is connected with the input end of the isolation module, and the isolation module is used for sending the PWM voltage signal to the filtering module; the output end of the isolation module is connected with the filtering module, and the filtering module is used for converting the PWM voltage signal into a motor rotating speed control signal. The embodiment of the utility model can construct a signal modulation circuit by using a common low-cost optocoupler, matching with a comparison device chip and a plurality of resistors and capacitors, thereby realizing the isolated transmission of voltage signals and solving the problems of high device cost in the prior art that the linear isolated optocoupler is adopted to realize the isolated transmission of the voltage signals; the isolation module in the embodiment of the utility model uses a common optocoupler, and the conversion module and the sawtooth wave module adopt low-cost devices such as a comparator to skillfully construct a circuit, thereby not only meeting the requirements of strong and weak electric isolation, but also realizing the isolated transmission of analog voltage signals and reducing the cost.
Fig. 3 is a schematic circuit diagram of an optical coupling isolated voltage transmission circuit according to an embodiment of the present utility model, and referring to fig. 3, optionally, the voltage dividing module includes: a double diode D7, a first resistor R69, a first capacitor C68, a second resistor R77, a second capacitor C69 and a third capacitor C40; the first end of the double diode D7 is connected with the internal power supply end +5VA, the second end of the double diode D7 is connected with the first end 1 of the external power supply module 10, the second end 2 of the external power supply module 10 is connected with the first end of the first resistor R69, and the second end of the first resistor R69 is connected with the third end of the double diode D7; the second end of the first resistor R69 is connected to the first ends of the second resistor R77, the second capacitor C69 and the third capacitor C40, the second ends of the second resistor R77, the second capacitor C69 and the third capacitor C40 are connected to the second end of the first capacitor C68 and then grounded GND-control, the first end of the first capacitor C68 is connected to the first end of the first resistor R69, and the first end of the third capacitor C68 serves as the output end of the voltage dividing module 20.
Specifically, the voltage of 0-10V (from the line controller) output by the external power supply module 10 is divided by a voltage dividing circuit composed of a first resistor R69, a second resistor R77, a first capacitor C68, a second capacitor C69, a third capacitor C40 and a double diode D7, so as to obtain a corresponding voltage range value of 0-4.31V, and then the corresponding voltage range value is input to the inverting input end (pin 2 of U10A) of the second comparator in the conversion module 40.
The dual diode D7 is typically used for clamping or protection in the circuit, and the dual diode D7 may be of the type BAT54S. The resistance value of the first resistor R69 is 68KΩ, the model number of the first capacitor C68 is 104/50V, the resistance value of the second resistor R77 is 47KΩ, the model number of the second capacitor C69 is 1uF/16V, and the model number of the third capacitor C40 is 104/16V.
With continued reference to fig. 3, optionally the sawtooth module 30 includes: a third resistor R52, a fourth capacitor C58, a fourth resistor R56, a fifth resistor R49, a sixth resistor R55, a fifth capacitor C59, a seventh resistor R54, a sixth capacitor C57, and a first comparator U10B; the first end of the third resistor R52 is connected to the internal power supply +5va, the second end of the third resistor R52 is connected to the first end 5 of the first comparator U10B, the first end of the fourth capacitor C58 and the first end of the fourth resistor R56 are both connected to the second end of the third resistor R52, the second end of the fourth resistor C58 and the second end of the fourth resistor R56 are connected to the ground GND-control, the fifth resistor R49 is connected between the first end 5 and the output end 7 of the first comparator U10B, the second end 6 of the first comparator U10B serves as the output end of the sawtooth module 30, the output end 7 of the first comparator U10B is connected to the first end of the sixth resistor R55 and the first end of the fifth capacitor C59, the second end of the fifth capacitor C59 is grounded GND-control, the first end of the seventh resistor R54 is connected to the internal power supply +5va, the second end of the second resistor R54 is connected to the second end of the sixth resistor C57, and the second end of the fourth resistor R54 is connected to the second end of the fourth resistor C57.
Specifically, a sawtooth wave circuit is built by using a third resistor R52, a fourth resistor R56, a fifth capacitor C58, a fifth resistor R49, a sixth resistor R55, a seventh resistor R54, a fifth capacitor C59, a sixth capacitor C57 and a first comparator U10B, and a sawtooth wave voltage waveform is obtained at the inverting input terminal (6 pins of U10B) of the first comparator U10B by utilizing the difference in charge and discharge speeds of the sixth capacitor C57 and the fourth capacitor C58.
The specific saw tooth wave obtaining principle is as follows: at the power-up time T0, the voltage at the 5 pin of the first comparator U10B (i.e., the terminal voltage of the fourth capacitor C58) is quickly charged from +5va to about 4.6V through the third resistor R52, while the charging time of the voltage at the 6 pin of the first comparator U10B (i.e., the terminal voltage of the sixth capacitor C57) is slow, and the time when the 6 pin of the first comparator U10B is charged to 4.6V is denoted as T1, and the voltage at the 6 pin of the first comparator U10B is charged up in an exponential manner during the time period from T0 to T1. At time T1, if the voltage at the 6 pins of the first comparator U10B is greater than the voltage at the 5 pins, the output at the 7 pins of the first comparator U10B changes from high to low, both the fourth capacitor C58 and the sixth capacitor C57 begin to discharge, and since the capacitance of the fourth capacitor C58 is small, the discharge will be faster than the discharge of the sixth capacitor C57, but the minimum voltage of the fourth capacitor C58 is determined by the divided voltage value of the third resistor R52 and the fifth resistor R49, the minimum voltage is 0.3V, and the saturated voltage drop at the output end of the first comparator U10B is 0.4V, i.e. the minimum voltage after the fourth capacitor C58 discharges is 0.7V, and at time T3, the voltage at the 6 pins of the first comparator U10B discharges to <0.7V, i.e. the voltage at the 6 pins of the first comparator U10B is less than the voltage at the 5 pins, and the output of the first comparator U10B changes from low to high. The sixth capacitor C57 and the fourth capacitor C58 are charged and discharged repeatedly, so the 6 pin of the first comparator U10B can obtain a sawtooth wave, and T0 to T3 are periods of the sawtooth wave.
The resistance of the third resistor R52 is 9.1KΩ, the model of the fourth capacitor C58 is 100pF/25V, the resistance of the fourth resistor R56 is 75KΩ, the resistance of the fifth resistor R49 is 510 Ω, the resistance of the sixth resistor R55 is 100 Ω, the model of the fifth capacitor C59 is 100pF/25V, the resistance of the seventh resistor R54 is 5.1KΩ, the model of the sixth capacitor C57 is 104/0603, and the model of the first comparator U10B is BA10393F.
With continued reference to fig. 3, the conversion module 40 optionally includes: a second comparator U10A and a seventh capacitance C12; the first end 2 of the second comparator U10A is connected with the output end of the voltage dividing module 20, the second end 3 of the second comparator U10A is connected with the output end of the sawtooth wave module 30, the third end 8 of the second comparator U10A is connected with the first end of the seventh capacitor C12, the first end of the seventh capacitor C12 is connected with the internal power supply end +5VA, the second end of the seventh capacitor C12 is grounded GND-control, the fourth end 4 of the second comparator U10A is grounded GND-control, and the output end 1 of the second comparator U10A serves as the output end of the conversion module 40.
Specifically, fig. 4 is a waveform diagram of a second comparator in an optocoupler isolated voltage transmission circuit according to an embodiment of the present utility model, and referring to fig. 3 and 4, waveforms of pin 3 of the second comparator U10A, pin 2 of the second comparator U10A, and pin 1 of the second comparator U10A are shown in fig. 4. The obtained sawtooth voltage is input to the 3 pin (non-inverting input end) of the second comparator U10A, the obtained preset voltage is input to the 2 pin (inverting input end) of the second comparator U10A, and then the 1 pin of the second comparator U10A outputs PWM voltage signal waveforms with adjustable duty ratio, so that the conversion from analog signals to digital signals is realized. The model of the second comparator U10A is BA10393F, and the model of the seventh capacitor C12 is 104/16V.
With continued reference to fig. 3, optionally, isolation module 50 includes an eighth resistor R70, a ninth resistor R66, and an optocoupler U8; the first end of the eighth resistor R70 is connected to the output end of the conversion module 40, the second end of the eighth resistor R70 is connected to the second end of the ninth resistor R66, the first end of the ninth resistor R66 is connected to the internal power supply end +5va, the ninth resistor R66 is connected between the first end 1 and the second end 2 of the optocoupler U8, the fourth end 4 of the optocoupler U8 is grounded GND-control, and the third end 3 of the optocoupler U8 is used as the output end of the isolation module 50.
Specifically, the PWM voltage signal is input to an optocoupler isolation circuit composed of an eighth resistor R70, a ninth resistor R66, and an optocoupler U8, and the PWM voltage signal is transmitted from the primary of the optocoupler U8 to the secondary of the optocoupler U8 by controlling the on/off of the optocoupler U8. The primary side of the optical coupler U8 refers to a light emitter (infrared Light Emitting Diode (LED)) in the optical coupler, and the secondary side of the optical coupler U8 refers to a light receiver (photosensitive semiconductor tube, photoresistor) in the optical coupler
The eighth resistor R70 has a resistance value of 820 omega, the ninth resistor R66 has a resistance value of 47KΩ, the optical coupler U8 has a model of PC817, the linear optical coupler is 7-8 times more expensive than the common optical coupler, and a common optical coupler is selected for constructing a circuit, so that the requirements of strong and weak electric isolation are met, the isolated transmission of analog voltage signals can be realized, and the circuit has higher cost advantage compared with the prior art.
With continued reference to fig. 3, optionally, the filtering module 60 includes a tenth resistor R61, an eleventh resistor R64, an eighth capacitor E14, and a ninth capacitor C65; the first end of the tenth resistor R61 is connected to the internal power supply terminal +5va, the second end of the tenth resistor R61 and the first end of the eleventh resistor R64 are connected to the output terminal of the isolation module 50, the second end of the eleventh resistor R64 is connected to the first end of the eighth capacitor E14 and the first end of the ninth capacitor C65, the second end of the eighth capacitor E14 and the second end of the ninth capacitor C65 are connected to the ground GND-control, and the first end of the ninth capacitor C65 is used as the output terminal of the filtering module 60.
Specifically, after passing through a smoothing filter circuit composed of a tenth resistor R61, an eleventh resistor R64, an eighth capacitor E14, and a ninth capacitor C65, the PWM voltage signal outputted from the secondary of the optocoupler U8 is converted from a digital signal (PWM voltage signal) to an analog signal (VSP voltage). The tenth resistor R61 has a resistance of 2KΩ, the eleventh resistor R64 has a resistance of 2KΩ, the eighth capacitor E14 is an electrolytic capacitor, and the model is 470uF/10V, and the model of the ninth capacitor C65 is 104/50V.
With continued reference to fig. 3, alternatively, the first comparator U10B is a voltage comparator and the second comparator U10A is a voltage comparator.
In particular, the voltage comparator may be used as an interface to analog and digital circuits, as well as to waveform generation and conversion circuits. Using a simple voltage comparator, the sine wave can become a square wave or rectangular wave of the same frequency.
Fig. 5 is a schematic structural diagram of still another optocoupler isolation voltage transmission circuit according to an embodiment of the present utility model, referring to fig. 5, optionally, the optocoupler isolation voltage transmission circuit further includes a microcontroller module 70, where the microcontroller module 70 is connected to the filtering module 60, and the microcontroller module 70 is configured to adjust a rotation speed of the motor according to a motor rotation speed control signal.
Specifically, the microcontroller module 70 may be a microcontroller or a single-chip microcomputer, and detects the voltage transmitted from the optocoupler secondary in real time, thereby realizing motor rotation speed control.
With continued reference to fig. 5, the input voltage of the external power module 10 may alternatively range from 0-10V.
Specifically, when the output voltage of the external power supply module 10 is continuously and incrementally changed from 0V to 10V, the microcontroller module 70 measures the VSP voltage value corresponding to the optocoupler secondary transmitted to the isolation module 50, and creates a corresponding data table.
Fig. 6 is a schematic diagram of a working process of an optical coupler isolation voltage transmission circuit according to an embodiment of the present utility model, and referring to fig. 6, the optical coupler isolation voltage transmission circuit performs hardware PWM modulation under the combined action of an input voltage division module, a sawtooth wave module and a conversion module of an external power supply module, performs isolation transmission through a common optical coupler in the isolation module, performs PWM filtering smoothing of a filtering module, and finally performs MCU detection through a microcontroller module, thereby realizing real-time control of a motor rotation speed.
The embodiment of the utility model also provides a frequency converter driving board which comprises the optocoupler isolation voltage transmission circuit provided by any embodiment of the utility model.
Because the frequency converter driving board comprises the optocoupler isolation voltage transmission circuit provided by any embodiment of the utility model, the frequency converter driving board has the same beneficial effects as the optocoupler isolation voltage transmission circuit, and the description is omitted here.
The above embodiments do not limit the scope of the present utility model. It will be apparent to those skilled in the art that various modifications, combinations, sub-combinations and alternatives are possible, depending on design requirements and other factors. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present utility model should be included in the scope of the present utility model.
Claims (10)
1. An optocoupler isolated voltage transmission circuit, comprising: the device comprises an external power supply module, a voltage division module, a sawtooth wave module, a conversion module, an isolation module and a filtering module;
the input end of the voltage dividing module is connected with the external power supply module, and the output end of the voltage dividing module is connected with the first input end of the conversion module; the voltage dividing module is used for converting the power supply voltage input by the external power supply module into preset voltage and sending the preset voltage to the conversion module;
the sawtooth wave module is used for generating sawtooth wave voltage and sending the sawtooth wave voltage to the conversion module, and the output end of the sawtooth wave module is connected with the second input end of the conversion module;
the conversion module is used for generating PWM voltage signals according to the received preset voltage and the received sawtooth voltage and sending the PWM voltage signals to the isolation module; the output end of the conversion module is connected with the input end of the isolation module, and the isolation module is used for sending the PWM voltage signal to the filtering module;
the output end of the isolation module is connected with the filtering module, and the filtering module is used for converting the PWM voltage signal into a motor rotating speed control signal.
2. The circuit of claim 1, wherein the voltage divider module comprises: a dual diode, a first resistor, a first capacitor, a second resistor, a second capacitor, and a third capacitor;
the first end of the double diode is connected with the internal power supply end, the second end of the double diode is connected with the first end of the external power supply module, the second end of the external power supply module is connected with the first end of the first resistor, and the second end of the first resistor is connected with the third end of the double diode;
the second end of the first resistor is respectively connected with the second resistor, the second capacitor and the first end of the third capacitor, the second end of the second resistor, the second capacitor and the second end of the third capacitor are connected with the second end of the first capacitor and then grounded, the first end of the first capacitor is connected with the first end of the first resistor, and the first end of the third capacitor is used as the output end of the voltage dividing module.
3. The circuit of claim 1, wherein the sawtooth module comprises: a third resistor, a fourth capacitor, a fourth resistor, a fifth resistor, a sixth resistor, a fifth capacitor, a seventh resistor, a sixth capacitor and a first comparator;
the first end of the third resistor is connected with the internal power supply end, the second end of the third resistor is connected with the first end of the first comparator, the first end of the fourth resistor and the first end of the fourth resistor are both connected with the second end of the third resistor, the second end of the fourth resistor and the second end of the fourth resistor are connected to the ground after being connected, the fifth resistor is connected between the first end and the output end of the first comparator, the second end of the first comparator serves as the output end of the sawtooth wave module, the output end of the first comparator is connected with the first end of the sixth resistor and the first end of the fifth capacitor respectively, the second end of the fifth resistor is grounded, the second end of the sixth resistor is connected with the second end of the seventh resistor, the first end of the seventh resistor is connected with the internal power supply end, the second end of the seventh resistor is connected with the first end of the sixth capacitor, the second end of the sixth resistor is connected with the first end of the sixth capacitor, and the second end of the sixth capacitor is connected with the first end of the sixth capacitor.
4. A circuit according to claim 3, wherein the conversion module comprises: a second comparator and a seventh capacitance;
the first end of the second comparator is connected with the output end of the voltage dividing module, the second end of the second comparator is connected with the output end of the sawtooth wave module, the third end of the second comparator is connected with the first end of the seventh capacitor, the first end of the seventh capacitor is connected with the internal power supply end, the second end of the seventh capacitor is grounded, the fourth end of the second comparator is grounded, and the output end of the second comparator is used as the output end of the conversion module.
5. The circuit of claim 1, wherein the isolation module comprises an eighth resistor, a ninth resistor, and an optocoupler;
the first end of the eighth resistor is connected with the output end of the conversion module, the second end of the eighth resistor is connected with the second end of the ninth resistor, the first end of the ninth resistor is connected with the internal power supply end, the ninth resistor is connected between the first end and the second end of the optocoupler, the fourth end of the optocoupler is grounded, and the third end of the optocoupler is used as the output end of the isolation module.
6. The circuit of claim 1, wherein the filter module comprises a tenth resistor, an eleventh resistor, an eighth capacitor, and a ninth capacitor;
the first end of the tenth resistor is connected with the internal power supply end, the second end of the tenth resistor is connected with the first end of the eleventh resistor and then is connected with the output end of the isolation module, the second end of the eleventh resistor is respectively connected with the first end of the eighth capacitor and the first end of the ninth capacitor, the second end of the eighth capacitor is connected with the second end of the ninth capacitor and then is grounded, and the first end of the ninth capacitor is used as the output end of the filtering module.
7. The circuit of claim 4, wherein the first comparator is a voltage comparator and the second comparator is a voltage comparator.
8. The circuit of claim 1, further comprising a microcontroller module coupled to the filter module, the microcontroller module configured to regulate a rotational speed of the motor based on the motor rotational speed control signal.
9. The circuit of claim 1, wherein the input voltage of the external power supply module ranges from 0-10V.
10. A frequency converter drive board comprising an optocoupler isolated voltage transmission circuit according to any one of claims 1-9.
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| Application Number | Priority Date | Filing Date | Title |
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| CN202223523438.7U CN219145368U (en) | 2022-12-26 | 2022-12-26 | Optocoupler isolation voltage transmission circuit and frequency converter drive plate |
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| Application Number | Priority Date | Filing Date | Title |
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| CN202223523438.7U CN219145368U (en) | 2022-12-26 | 2022-12-26 | Optocoupler isolation voltage transmission circuit and frequency converter drive plate |
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| CN202223523438.7U Active CN219145368U (en) | 2022-12-26 | 2022-12-26 | Optocoupler isolation voltage transmission circuit and frequency converter drive plate |
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