Analog input interface circuit of frequency converter

Abstract

The utility model relates to an analog input interface circuit of a frequency converter, which is characterized in that at least one micro toggle switch is arranged in an input signal circuit, a signal processing circuit is connected with the output end of the input signal circuit, and an output circuit is connected with the output end of the signal processing circuit and is used for outputting processed signals to a microcontroller, the micro toggle switch allows to adapt to different input signal forms by changing the state of the micro toggle switch under the condition that an input signal circuit is not changed. Through simple transformation of an existing analog input interface, receiving and conversion processing of PWM pulse width modulation voltage signal input can be realized, and a special high-speed interface and software processing overhead can be saved.

Description

Technical Field

[0001] The utility model relates to a frequency converter analog input interface circuit, belonging to the technical field of electrical engineering and automatic control. Background Art

[0002] With the rapid development of industrial automation and intelligent manufacturing, the performance and reliability of the inverter, as the core component of the electric power transmission system, are crucial to the stability and efficiency of the entire system. The inverter achieves precise control of the motor speed and torque by adjusting the power supply frequency and voltage of the motor.

[0003] In the actual application of frequency converters, accurate input of external control signals is the key to achieving precise control. Traditional frequency converters usually provide analog input interfaces for receiving external voltage or current signals. These signals are usually used to set the output frequency of the frequency converter to control the speed of the motor. However, existing frequency converter analog input interfaces have certain limitations. For example, they can only process limited types of analog signals and cannot directly receive and process PWM signals. In order to realize the input of PWM signals, it is usually necessary to add additional dedicated digital signal ports, which not only increases the hardware cost, but also makes the system more complicated. Utility Model Content

[0004] In view of the deficiencies in the prior art, the purpose of the utility model is to provide a frequency converter analog input interface circuit to solve the problem that the existing frequency converter analog input interface has certain limitations on signal types and cannot directly receive and process PWM signals.

[0005] In order to achieve the above object, the utility model is implemented through the following technical solutions: a frequency converter analog input interface circuit, which includes:

[0006] An input signal circuit, wherein at least one micro toggle switch is provided inside the input signal circuit;

[0007] A signal processing circuit, the signal processing circuit is connected to the output end of the input signal selection circuit and is used to convert the input signal into a signal that is easy for the controller to process;

[0008] an output circuit, the output circuit being connected to the output end of the signal processing circuit and being used to output the processed signal to the microcontroller,

[0009] The micro toggle switch includes switch S1, switch S2, and switch S3.

[0010] The micro toggle switch S1, switch S2 and switch S3 can adapt to different input signal forms by changing the state without changing the input signal circuit (1).

[0011] Furthermore, the signal processing circuit includes a common-phase operational amplifier U1 for processing input signals and a filter circuit composed of a resistor R1 and a capacitor C1.

[0012] Furthermore, the in-phase operational amplifier U1 converts the input signal selected by the input signal circuit into a signal suitable for processing by the microcontroller, and the filter circuit is used to convert the PWM signal into a DC signal.

[0013] Furthermore, the input signal circuit can receive four different signal input forms, which are: 0-10vdc analog signal input, 0-20mAdc analog signal input, push-pull PWM1 signal input and open collector PWM2 signal input.

[0014] Furthermore, when the input signal is a 0-10vdc analog signal input, the switch S1 and the switch S2 are disconnected, and the switch S3 is closed or disconnected, and a 0-10vdc analog voltage input is obtained at the non-inverting input terminal of the non-inverting operational amplifier U1.

[0015] Furthermore, when the input signal is a 0-20mAdc analog signal input, switches S1 and S3 are closed, switch S2 is opened, and the input signal is converted into a voltage signal through switch S1 and resistor R2, and an analog voltage input of 0-10Vdc or 0-5Vdc is obtained at the non-inverting input terminal of the non-inverting operational amplifier U1.

[0016] Furthermore, when the input signal is a push-pull PWM1 signal input, switches S1, S2 and S3 are disconnected, and the voltage amplitude of the push-pull input 12V or 24V is divided into a PWM signal of 5V or 10V through the voltage dividing effect of resistors R11 and R12. The PWM signal is filtered by resistor R1 and capacitor C1 and converted into a DC signal of 0-5V or 0-10V, which is input into the non-inverting input terminal of the non-inverting operational amplifier U1.

[0017] Furthermore, when the input signal is an open collector PWM2 signal input, switch S1 is disconnected, switch S2 is closed, and switch S3 is closed or disconnected. The PWM voltage amplitude of the open collector input is +10Vref set by the pull-up resistor R10. Through the filtering effect of the resistor R1 and the capacitor C1, if S3 is disconnected, the filtering is performed by the resistor R11, the resistor R1 and the capacitor C1 to convert the 0-10V DC signal into the non-inverting input terminal of the non-inverting operational amplifier U1.

[0018] The beneficial effects of the utility model are:

[0019] When a user uses a frequency converter analog input interface circuit, different input signal types can be handled by combining different switch states of micro switch S1, micro switch S2 and micro switch S3. When the input signal is output through the input signal circuit and enters the signal processing circuit, the filter circuit and the in-phase operational amplifier in the signal processing circuit will convert the input signal into an easy-to-process signal, and finally transmit it to the AD port of the MCU through the output circuit. The utility model solves the limitations of the existing frequency converter analog input interface, and can realize 0-10vdc analog signal input, 0-20mAdc analog signal input, push-pull PWM1 signal input and open collector PWM2 signal input without adding additional digital signal ports, greatly improving the practicality of the overall circuit. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Other features, objects and advantages of the present invention will become more apparent by reading the detailed description of non-limiting embodiments with reference to the following drawings:

[0021] Figure 1 This is a schematic diagram of the structure of a frequency converter analog input interface circuit of the utility model;

[0022] Figure 2 It is the circuit form of the PWM signal source in the input signal circuit;

[0023] Figure 3 Select schematic diagrams for the states of the switches under different input signals.

[0024] The reference numerals are: 1. input signal circuit; 2. signal processing circuit; 3. output circuit. DETAILED DESCRIPTION

[0025] In order to make the technical means, creative features, objectives and effects achieved by the present invention easy to understand, the present invention is further described below in conjunction with specific implementation methods.

[0026] Figure 1 The utility model is a schematic diagram of the structure of a frequency converter analog input interface circuit.

[0027] like Figure 1 As shown, the utility model provides a technical solution for a frequency converter analog input interface circuit: it includes:

[0028] An input signal circuit 1, wherein at least one micro toggle switch is provided inside the input signal circuit 1;

[0029] A signal processing circuit 2, the signal processing circuit 2 is connected to the output end of the input signal selection circuit 1, and is used to convert the input signal into a signal that is easy for the controller to process;

[0030] The output circuit 3 is connected to the output end of the signal processing circuit 2 and is used to output the processed signal to the microcontroller.

[0031] The micro toggle switch includes switch S1, switch S2, and switch S3.

[0032] The micro toggle switch S1, switch S2 and switch S3 can adapt to different input signal forms by changing the state without changing the input signal circuit (1).

[0033] In order to adapt to different input signals, the signal processing circuit 2 includes a common-phase operational amplifier U1 for processing the input signal and a filter circuit composed of a resistor R1 and a capacitor C1.

[0034] In order to improve the adaptability of the signal, the in-phase operational amplifier U1 converts the input signal selected by the input signal circuit 1 into a signal suitable for processing by the microcontroller, and the filter circuit is used to convert the PWM signal into a DC signal.

[0035] Figure 2 It is the circuit form of the PWM signal source in the input signal circuit. Figure 3 Select the schematic diagram for the switch status under different input signals. Figure 2 and Figure 3 As shown, in order to improve the compatibility level of the circuit, the utility model also provides a frequency converter analog input interface circuit, the input signal circuit 1 can receive 4 different signal input forms, the signal input forms are: 0-10vdc analog signal input, 0-20mAdc analog signal input, push-pull PWM1 signal input and open collector PWM2 signal input.

[0036] In order to simplify the circuit's processing of standard voltage signals, when the input signal is a 0-10vdc analog signal input, switches S1 and S2 are disconnected, and switch S3 is closed or disconnected, and a 0-10vdc analog voltage input is obtained at the non-inverting input terminal of the non-inverting operational amplifier U1.

[0037] In order to facilitate the microcontroller to perform signal processing, when the input signal is a 0-20mAdc analog signal input, switches S1 and S3 are closed, and switch S2 is opened. The input signal is converted into a voltage signal through switch S1 and resistor R2, and an analog voltage input of 0-10Vdc or 0-5Vdc is obtained at the non-inverting input terminal of the non-inverting operational amplifier U1.

[0038] In order to extract a valid control signal, when the input signal is a push-pull PWM1 signal input, switches S1, S2 and S3 are disconnected, and the voltage amplitude of the push-pull input 12V or 24V is divided into a 5V or 10V PWM signal through the voltage dividing effect of resistors R11 and R12. The PWM signal is filtered by resistor R1 and capacitor C1 and converted into a 0-5V or 0-10V DC signal, which is input into the non-inverting input terminal of the non-inverting operational amplifier U1.

[0039] In order to convert and process a special form of PWM signal, when the input signal is an open collector PWM2 signal input, switch S1 is disconnected, switch S2 is closed, switch S3 is closed or disconnected, and the PWM voltage amplitude of the open collector input is +10Vref set by the pull-up resistor R10. Through the filtering effect of resistor R1 and capacitor C1, if S3 is disconnected, the filtering is performed by resistor R11, resistor R1 and capacitor C1 to convert the 0-10V DC signal into the non-inverting input terminal of the non-inverting operational amplifier U1.

[0040] When a user uses a frequency converter analog input interface circuit, different input signal types can be handled by combining different switch states of micro switch S1, micro switch S2 and micro switch S3. When the input signal is output through the input signal circuit and enters the signal processing circuit, the filter circuit and the in-phase operational amplifier in the signal processing circuit will convert the input signal into an easy-to-process signal, and finally transmit it to the AD port of the MCU through the output circuit. The utility model solves the limitations of the existing frequency converter analog input interface, and can realize 0-10vdc analog signal input, 0-20mAdc analog signal input, push-pull PWM1 signal input and open collector PWM2 signal input without adding additional digital signal ports, greatly improving the practicality of the overall circuit.

[0041] The above shows and describes the basic principles and main features of the utility model and the advantages of the utility model. For those skilled in the art, it is obvious that the utility model is not limited to the details of the above exemplary embodiments, and can be implemented in other specific forms without departing from the spirit or basic features of the utility model. Therefore, no matter from which point of view, the embodiments should be regarded as exemplary and non-restrictive. The scope of the utility model is limited by the attached claims rather than the above description, and it is intended to include all changes within the meaning and scope of the equivalent elements of the claims. Any figure mark in the claims should not be regarded as limiting the claims involved.

[0042] In addition, it should be understood that although the present specification is described according to implementation modes, not every implementation mode contains only one independent technical solution. This description of the specification is only for the sake of clarity. Those skilled in the art should regard the specification as a whole. The technical solutions in each embodiment may also be appropriately combined to form other implementation modes that can be understood by those skilled in the art.

Claims

1. A frequency converter analog input interface circuit, characterized in that: It includes: An input signal circuit (1), wherein at least one micro toggle switch is provided inside the input signal circuit (1); A signal processing circuit (2), the signal processing circuit (2) being connected to the output end of the input signal selection circuit (1) and used for converting the input signal into a signal that is easy for the controller to process; An output circuit (3), the output circuit (3) is connected to the output end of the signal processing circuit (2) and is used to output the processed signal to the microcontroller, The micro toggle switch includes switch S1, switch S2, and switch S3. The micro toggle switch S1, switch S2 and switch S3 can adapt to different input signal forms by changing the state without changing the input signal circuit (1).

2. The frequency converter analog input interface circuit according to claim 1, characterized in that: The signal processing circuit (2) comprises a common-phase operational amplifier U1 for processing an input signal and a filter circuit composed of a resistor R1 and a capacitor C1.

3. The frequency converter analog input interface circuit according to claim 2, characterized in that: The in-phase operational amplifier U1 converts the input signal selected by the input signal circuit (1) into a signal suitable for processing by the microcontroller, and the filter circuit is used to convert the PWM signal into a DC signal.

4. The frequency converter analog input interface circuit according to claim 1, characterized in that: The input signal circuit (1) can receive four different signal input forms, which are: 0-10vdc analog signal input, 0-20mAdc analog signal input, push-pull PWM1 signal input and open collector PWM2 signal input.

5. The frequency converter analog input interface circuit according to claim 4, characterized in that: When the input signal is a 0-10vdc analog signal input, the switch S1 and the switch S2 are disconnected, and the switch S3 is closed or disconnected, and a 0-10vdc analog voltage input is obtained at the non-inverting input terminal of the non-inverting operational amplifier U1.

6. The frequency converter analog input interface circuit according to claim 4, characterized in that: When the input signal is a 0-20mAdc analog signal input, switches S1 and S3 are closed, switch S2 is opened, and the input signal is converted into a voltage signal through switch S1 and resistor R2, and an analog voltage input of 0-10Vdc or 0-5Vdc is obtained at the non-inverting input terminal of the non-inverting operational amplifier U1.

7. The frequency converter analog input interface circuit according to claim 4, characterized in that: When the input signal is a push-pull PWM1 signal input, switches S1, S2 and S3 are disconnected, and the voltage amplitude of the push-pull input 12V or 24V is divided into a 5V or 10V PWM signal through the voltage dividing effect of resistors R11 and R12. The PWM signal is filtered by resistor R1 and capacitor C1 and converted into a 0-5V or 0-10V DC signal, which is input into the non-inverting input terminal of the non-inverting operational amplifier U1.

8. The frequency converter analog input interface circuit according to claim 4, characterized in that: When the input signal is an open collector PWM2 signal input, switch S1 is disconnected, switch S2 is closed, and switch S3 is closed or disconnected. The PWM voltage amplitude of the open collector input is +10Vref set by the pull-up resistor R10. Through the filtering effect of the resistor R1 and the capacitor C1, if S3 is disconnected, the filtering is performed by the resistor R11, the resistor R1 and the capacitor C1 to convert the 0-10V DC signal into the non-inverting input terminal of the non-inverting operational amplifier U1.

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