Overcurrent protection reference circuit based on PWM modulation

Abstract

This application relates to the field of inverter overcurrent protection circuit technology, and particularly to an overcurrent protection reference circuit based on PWM modulation. The circuit includes a main control MCU, a filter circuit, an operational amplifier circuit, and an inverter circuit. The main control MCU is electrically connected to the filter circuit, and the operational amplifier circuit is electrically connected to both the filter circuit and the inverter circuit. The signal emitted by the main control MCU passes through the filter circuit to generate a corresponding voltage value. This voltage value is then processed by the operational amplifier circuit to generate a positive overcurrent protection voltage reference point. The positive overcurrent protection voltage reference point is then processed by the inverter circuit to generate a negative overcurrent protection voltage reference point. This application allows for flexible adjustment of the overcurrent protection voltage reference point by adjusting the duty cycle of the PWM signal through the main control MCU, without requiring disassembly or modification of hardware parameters. This reduces operational complexity and costs.

Description

Technical Field

[0001] This application relates to the field of inverter overcurrent protection circuit technology, and in particular to an overcurrent protection reference circuit based on PWM modulation. Background Technology

[0002] With the rapid development of electronic power technology, the demand for flexibility in the overcurrent protection reference circuit of frequency converter products is becoming increasingly strong. Most of the overcurrent protection voltage reference points on the market are obtained by generating fixed overcurrent protection voltage reference points through hardware solutions such as resistor voltage division. If it is necessary to modify the overcurrent protection voltage reference point, the hardware parameters must be modified by disassembling the machine, which is relatively cumbersome.

[0003] Therefore, existing technologies have shortcomings and need to be improved. Summary of the Invention

[0004] In a first aspect, this application provides an overcurrent protection reference circuit based on PWM modulation, including a main control MCU, a filter circuit, an operational amplifier circuit, and an inverter circuit. The main control MCU is electrically connected to the filter circuit, and the operational amplifier circuit is electrically connected to both the filter circuit and the inverter circuit. The signal emitted by the main control MCU passes through the filter circuit to generate a corresponding voltage value. This corresponding voltage value is processed by the operational amplifier circuit to generate a positive overcurrent protection voltage reference point. The positive overcurrent protection voltage reference point is processed by the inverter circuit to generate a negative overcurrent protection voltage reference point.

[0005] Optionally, the signal emitted by the main control MCU is an adjustable duty cycle PWM signal or a fixed voltage value.

[0006] Optionally, the filter circuit includes a resistor R3 and a capacitor C1. One end of the resistor R3 is electrically connected to the main control MCU, and the other end is electrically connected to one end of the capacitor C1 and the operational amplifier circuit. The other end of the capacitor C1 is grounded.

[0007] Optionally, the PWM-modulated overcurrent protection reference circuit further includes a voltage divider circuit, which is electrically connected to the main control MCU and the filter circuit respectively.

[0008] Optionally, the voltage divider circuit includes resistors R1 and R2. Resistor R1 is electrically connected to the main control MCU, one end of resistor R2, and the filter circuit, respectively, and the other end of resistor R2 is grounded.

[0009] Optionally, the operational amplifier circuit includes operational amplifier U1-A, resistors R4, R5, R6, and R7, and capacitors C4, C3, and C2. Operational amplifier U1-A includes a 1IN- terminal, a 1IN+ terminal, a 1OUT terminal, a VCC- terminal, and a VCC+ terminal. The 1IN- terminal is electrically connected to one end of resistor R4 and one end of resistor R6. The 1IN+ terminal is electrically connected to one end of resistor R5 and one end of capacitor C2. The 1OUT terminal is electrically connected to one end of resistor R7. The VCC- terminal is electrically connected to one end of capacitor C3. The VCC+ terminal is electrically connected to one end of capacitor C4. The other end of resistor R4 is grounded. The other end of resistor R6 is electrically connected to the other end of resistor R7 and the inverter circuit. The other end of resistor R5 is electrically connected to the filter circuit. The other end of capacitor C2 is grounded. The other end of capacitor C3 is grounded. The other end of capacitor C4 is grounded.

[0010] Optionally, the inverter circuit includes inverter U1-B, resistors R8, R9, R10, and R11. Inverter U1-B includes a 2IN- terminal, a 2IN+ terminal, and a 2OUT terminal. The 2IN- terminal is electrically connected to one end of resistor R8 and one end of resistor R10, respectively. The 2IN+ terminal is electrically connected to one end of resistor R9. The 2OUT terminal is electrically connected to one end of resistor R11. The other end of resistor R8 is electrically connected to the operational amplifier circuit. The other end of resistor R9 is grounded. The other end of resistor R10 is electrically connected to the other end of resistor R11.

[0011] Optionally, the other end of resistor R7 is electrically connected to the other end of resistor R8.

[0012] The technical solutions provided in this application have the following advantages compared with the prior art:

[0013] In this embodiment, a PWM signal with a fixed frequency and adjustable duty cycle is emitted by the main control MCU. After passing through a filtering circuit, a corresponding DC voltage value is generated, which is then passed through an operational amplifier circuit to generate a corresponding overcurrent protection voltage reference point. By adjusting the duty cycle of the PWM signal through the main control MCU, the corresponding overcurrent protection voltage reference point can be flexibly adjusted without disassembling the device or modifying hardware parameters, which helps to reduce the complexity of operation and reduce operating costs. Attached Figure Description

[0014] The accompanying drawings, which are incorporated in and form part of this specification, illustrate embodiments consistent with this application and, together with the description, serve to explain the principles of this application.

[0015] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, for those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0016] One or more embodiments are illustrated by way of example with reference numerals in the accompanying drawings. These illustrations do not constitute a limitation on the embodiments. Elements with the same reference numerals in the drawings are denoted as similar elements. Unless otherwise stated, the figures in the drawings are not to be limited by scale.

[0017] Figure 1 This is a specific circuit diagram of an overcurrent protection reference circuit based on PWM modulation provided in an embodiment of this application.

[0018] Figure 2 for Figure 1 The specific circuit diagram of the filter circuit.

[0019] Figure 3 for Figure 1 The specific circuit diagram of the operational amplifier circuit.

[0020] Figure 4 for Figure 1 The detailed circuit diagram of the inverter circuit.

[0021] Figure 5 for Figure 1 The specific circuit diagram of the voltage divider circuit.

[0022] Explanation of reference numerals in the attached figures:

[0023] 1. Filter circuit; 2. Operational amplifier circuit; 3. Inverter circuit; 4. Voltage divider circuit. Detailed Implementation

[0024] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, the technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0025] The following disclosure provides numerous different embodiments or examples for implementing various structures of this application. To simplify the disclosure, specific examples of components and arrangements are described below. These are merely examples and are not intended to limit the scope of this application. Furthermore, reference numerals and / or letters may be repeated in different examples. Such repetition is for simplification and clarity and does not in itself indicate a relationship between the various embodiments and / or arrangements discussed.

[0026] For ease of description, spatial relative terms may be used in the text to describe the relative position or movement of one element or feature relative to another element or feature, as shown in the figure. These relative terms include, for example, "inside," "outside," "middle," "outer," "below," "below," "above," "front," "back," etc. Such spatial relative terms are intended to include different orientations of the device in use or operation, other than those depicted in the figure. For example, if the device in the figure undergoes a positional flip, orientation change, or change of motion, these directional indications will change accordingly. For instance, an element described as "below other elements or features" or "below other elements or features" will subsequently be oriented "above other elements or features" or "above other elements or features." Therefore, the example term "below" can include both upper and lower orientations. The device may be otherwise oriented (rotated 90 degrees or in other directions), and the spatial relative descriptors used in the text will be interpreted accordingly.

[0027] To address the technical problems in existing technologies, this application provides an overcurrent protection reference circuit based on PWM modulation. This circuit enables the main control MCU to output a PWM signal with a fixed frequency and adjustable duty cycle. After passing through a filtering circuit, a corresponding DC voltage value is generated, which is then passed through an operational amplifier circuit to generate the corresponding overcurrent protection voltage reference point. By adjusting the duty cycle of the PWM signal through the main control MCU, the corresponding overcurrent protection voltage reference point can be flexibly adjusted without disassembling the device or modifying hardware parameters, thus reducing operational complexity and costs.

[0028] Figure 1-5This application provides an overcurrent protection reference circuit based on PWM modulation, comprising a main control MCU, a filter circuit 1, an operational amplifier circuit 2, and an inverter circuit 3. The main control MCU is electrically connected to the filter circuit 1, and the operational amplifier circuit 2 is electrically connected to both the filter circuit 1 and the inverter circuit 3. The main control MCU outputs a PWM signal with a fixed frequency and adjustable duty cycle (OC_PWM), which, after passing through the filter circuit 1, generates a corresponding voltage value (OC-REF). This voltage value (OC-REF), after being processed by the operational amplifier circuit 2, generates a positive overcurrent protection voltage reference point (REF-H). The positive overcurrent protection voltage reference point (REF-H), after being processed by the inverter circuit 3, generates a negative overcurrent protection voltage reference point (REF-L). This PWM modulation-based overcurrent protection reference circuit allows for flexible adjustment of the corresponding overcurrent protection voltage reference point by adjusting the duty cycle of the PWM signal through the main control MCU. This can be achieved without disassembling the device or modifying hardware parameters, thus reducing operational complexity and costs.

[0029] Furthermore, the filter circuit 1 includes a resistor R3 and a capacitor C1. One end of the resistor R3 is electrically connected to the main control MCU, and the other end is electrically connected to one end of the capacitor C1 and the operational amplifier circuit 2. The other end of the capacitor C1 is grounded.

[0030] Please see Figure 5 The PWM-modulated overcurrent protection reference circuit further includes a voltage divider circuit 4, which is electrically connected to the main control MCU and the filter circuit 1. The voltage divider circuit 4 includes resistors R1 and R2. Resistor R1 is electrically connected to the main control MCU, one end of resistor R2, and the filter circuit 1, while the other end of resistor R2 is grounded. It can be understood that resistors R1 and R2 generate a fixed voltage value through resistor division. The purpose is to fix the OC_PWM signal to a fixed value when a program error causes no output, generating a fixed overcurrent protection voltage reference point. This avoids false overcurrent fault reports and overcurrent damage from the inverter, allowing the inverter to adapt to more complex load application scenarios.

[0031] Please see Figure 3The operational amplifier circuit 2 includes operational amplifier U1-A, resistors R4, R5, R6, and R7, and capacitors C4, C3, and C2. Operational amplifier U1-A includes a 1IN- terminal, a 1IN+ terminal, a 1OUT terminal, a VCC- terminal, and a VCC+ terminal. The 1IN- terminal is electrically connected to one end of resistor R4 and one end of resistor R6. The 1IN+ terminal is electrically connected to one end of resistor R5 and one end of capacitor C2. The 1OUT terminal is electrically connected to one end of resistor R7. The VCC- terminal is electrically connected to one end of capacitor C3. The VCC+ terminal is electrically connected to one end of capacitor C4. The other end of resistor R4 is grounded. The other end of resistor R6 is electrically connected to the other end of resistor R7 and inverter circuit 3. The other end of resistor R5 is electrically connected to filter circuit 1. The other end of capacitor C2 is grounded. The other end of capacitor C3 is grounded. The other end of capacitor C4 is grounded.

[0032] Please see Figure 4 The inverter circuit 3 includes an inverter U1-B, resistors R8, R9, R10, and R11. The inverter U1-B includes a 2IN- terminal, a 2IN+ terminal, and a 2OUT terminal. The 2IN- terminal is electrically connected to one end of resistor R8 and one end of resistor R10, respectively. The 2IN+ terminal is electrically connected to one end of resistor R9, and the 2OUT terminal is electrically connected to one end of resistor R11. The other end of resistor R8 is electrically connected to the operational amplifier circuit 2. The other end of resistor R9 is grounded, and the other end of resistor R10 is electrically connected to the other end of resistor R11. The other end of resistor R7 is electrically connected to the other end of resistor R8 to connect the operational amplifier circuit 2 and the inverter circuit 3.

[0033] In the above embodiments, the descriptions of each embodiment have different focuses. For parts that are not described in detail in a certain embodiment, please refer to the relevant descriptions in other embodiments.

[0034] In the description of this application, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this application.

[0035] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this application, "multiple" means two or more, unless otherwise explicitly specified.

[0036] In this application, unless otherwise expressly specified and limited, the terms "installation," "connection," "joining," and "fixing," etc., should be interpreted broadly. For example, they can refer to a connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components. Those skilled in the art can understand the specific meaning of the above terms in this application according to the specific circumstances.

[0037] In this application, unless otherwise expressly specified and limited, "above" or "below" the second feature can include direct contact between the first and second features, or contact between the first and second features through another feature between them. Furthermore, "above," "over," and "on top" of the second feature includes the first feature being directly above or diagonally above the second feature, or simply indicates that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature includes the first feature being directly below or diagonally below the second feature, or simply indicates that the first feature is at a lower horizontal level than the second feature.

[0038] In the description of this specification, the references to terms such as "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of this application. The illustrative expressions of the above terms in this specification should not be construed as necessarily referring to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples. In addition, those skilled in the art can combine and integrate the different embodiments or examples described in this specification.

[0039] Obviously, those skilled in the art can make various modifications and variations to this application without departing from the spirit and scope of this application. Since these modifications and variations fall within the scope of the claims and their equivalents, this application also intends to include these modifications and variations.

[0040] The above description describes specific embodiments of this application, but the scope of protection of this application is not limited thereto. Any person skilled in the art can easily conceive of various equivalent modifications or substitutions within the technical scope disclosed in this application, and these modifications or substitutions should all be covered within the scope of protection of this application. Therefore, the scope of protection of this application should be determined by the scope of the claims.

Claims

1. A PWM modulation based overcurrent protection reference circuit, characterized by: The system includes a main control MCU, a filter circuit, an operational amplifier circuit, and an inverter circuit. The main control MCU is electrically connected to the filter circuit, and the operational amplifier circuit is electrically connected to both the filter circuit and the inverter circuit. The signal sent by the main control MCU passes through the filter circuit to generate a corresponding voltage value. This corresponding voltage value is processed by the operational amplifier circuit to generate an overcurrent protection positive voltage reference point. The overcurrent protection positive voltage reference point is then processed by the inverter circuit to generate an overcurrent protection negative voltage reference point.

2. The PWM modulation based overcurrent protection reference circuit of claim 1, wherein: The signal emitted by the main control MCU is either an adjustable duty cycle PWM signal or a fixed voltage value.

3. The PWM modulation based overcurrent protection reference circuit of claim 1, wherein: The filter circuit includes a resistor R3 and a capacitor C1. One end of the resistor R3 is electrically connected to the main control MCU, and the other end is electrically connected to one end of the capacitor C1 and the operational amplifier circuit. The other end of the capacitor C1 is grounded.

4. The PWM modulation based overcurrent protection reference circuit of claim 3, wherein: The overcurrent protection reference circuit based on PWM modulation also includes a voltage divider circuit, which is electrically connected to the main control MCU and the filter circuit respectively.

5. The PWM modulation based overcurrent protection reference circuit of claim 4, wherein: The voltage divider circuit includes resistors R1 and R2. Resistor R1 is electrically connected to the main control MCU, one end of resistor R2, and the filter circuit, respectively, and the other end of resistor R2 is grounded.

6. The PWM modulation based overcurrent protection reference circuit of claim 1, wherein: The operational amplifier circuit includes operational amplifier U1-A, resistors R4, R5, R6, and R7, and capacitors C4, C3, and C2. Operational amplifier U1-A includes a 1IN- terminal, a 1IN+ terminal, a 1OUT terminal, a VCC- terminal, and a VCC+ terminal. The 1IN- terminal is electrically connected to one end of resistor R4 and one end of resistor R6. The 1IN+ terminal is electrically connected to one end of resistor R5 and one end of capacitor C2. The 1OUT terminal is electrically connected to one end of resistor R7. The VCC- terminal is electrically connected to one end of capacitor C3. The VCC+ terminal is electrically connected to one end of capacitor C4. The other end of resistor R4 is grounded. The other end of resistor R6 is electrically connected to the other end of resistor R7 and the inverter circuit. The other end of resistor R5 is electrically connected to the filter circuit. The other end of capacitor C2, capacitor C3, and capacitor C4 are all grounded.

7. The PWM modulation based overcurrent protection reference circuit of claim 6, wherein: The inverter circuit includes inverter U1-B, resistors R8, R9, R10, and R11. Inverter U1-B includes a 2IN- terminal, a 2IN+ terminal, and a 2OUT terminal. The 2IN- terminal is electrically connected to one end of resistor R8 and one end of resistor R10, respectively. The 2IN+ terminal is electrically connected to one end of resistor R9. The 2OUT terminal is electrically connected to one end of resistor R11. The other end of resistor R8 is electrically connected to the operational amplifier circuit. The other end of resistor R9 is grounded. The other end of resistor R10 is electrically connected to the other end of resistor R11.

8. The PWM modulation based overcurrent protection reference circuit of claim 7, wherein: The other end of resistor R7 is electrically connected to the other end of resistor R8.

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