Three-phase input line voltage detection method, detection system and detection circuit

Abstract

The invention provides a three-phase input line voltage detection method, system and circuit, and the method comprises the steps: enabling an equal-resistance resistor to be connected in parallel with a motor phase line at an input end, manufacturing a neutral point of a three-phase input PFC, and enabling the neutral point to be equivalent to a virtual N line; taking the virtual N line as a common ground point of a detection circuit; obtaining a three-phase phase voltage of the three-phase input PFC based on the detection circuit; and carrying out vector calculation based on the three-phase phase voltage to obtain the line voltage of the three-phase input PFC. A three-phase line neutral point is manufactured and can be equivalent to a virtual N line, then a three-phase input equivalent phase voltage waveform is detected by a three-way isolation operational amplifier detection circuit and is input into an MCU control chip after being isolated and amplified, and finally, the MCU control chip can derive a three-phase input line voltage according to a vector relation between a three-phase line voltage and a phase voltage.

Description

Technical Field

[0001] The present application belongs to the field of power electronics technology and relates to a voltage detection method, and in particular to a three-phase input line voltage detection method, a detection system and a detection circuit. Background Art

[0002] Three-phase alternating current is composed of three single-phase alternating currents with the same frequency, amplitude and phase difference of 120° (such as Figure 1 It is the most common form of power input on industrial equipment.

[0003] In many high-power power supply applications, a three-phase PFC rectifier is required. Its control circuit needs to monitor the input waveform of the three-phase line voltage in real time. The usual practice is to use a detection circuit with an operational amplifier as the core to detect the line voltage U AB , U BC , U CA ,For example Figure 2 A three-phase input line voltage detection circuit is shown. This line voltage detection circuit can convert the three-phase input voltage into a small voltage signal in real time, and provide it to the MCU control chip after being isolated from the strong voltage circuit.

[0004] However, this detection circuit has an obvious disadvantage: the common-mode input voltage of the isolated operational amplifier is difficult to increase (usually only a few volts to tens of volts), and the three-way isolated operational amplifier detection circuit cannot be made into a differential input at the same time; at the same time, three independent power supplies are required to power the primary side of the isolated operational amplifier, which makes the overall hardware circuit more complicated. In addition, the design of the switching power supply to power the isolated operational amplifier is also difficult. Summary of the invention

[0005] The purpose of the present application is to provide a three-phase input line voltage detection method, a detection system and a detection circuit, which are used to solve the problem in the prior art that the common-mode input voltage of the isolation operational amplifier is too small and limited because the detection circuit cannot make a differential input during detection, resulting in the overall hardware complexity of the detection circuit and the difficulty in designing a switching power supply.

[0006] In a first aspect, the present application provides a three-phase input line voltage detection method, the three-phase input line voltage detection method comprising: using equal-resistance resistors in parallel on the motor phase lines at the input end to produce a neutral point of the three-phase input PFC, and the neutral point is equivalent to a virtual N line; using the virtual N line as a common point of the detection circuit; obtaining the three-phase phase voltage of the three-phase input PFC based on the detection circuit; performing vector calculation based on the three-phase phase voltage to obtain the line voltage of the three-phase input PFC.

[0007] In an implementation of the first aspect, equal-resistance resistors are connected in parallel to the motor phase lines at the input end to produce a neutral point of the three-phase input PFC, and the neutral point is equivalent to a virtual N line, including: connecting equal-resistance resistors in parallel on the three-phase lines at the input end; obtaining the voltage between each phase line and the virtual N line; and using the midpoint of each of the equal-resistance resistors connected in parallel as the virtual N line.

[0008] In an implementation manner of the first aspect, obtaining the three-phase phase voltage of the three-phase input PFC based on the detection circuit includes: inputting the voltage on the three-phase input equivalent resistance group in the detection circuit into a three-way isolation operational amplifier to obtain the phase voltages Ua, Ub, and Uc of the three-phase input PFC; and inputting the phase voltage of the three-phase input PFC into an MCU module for processing.

[0009] In an implementation of the first aspect, the three-phase input equivalent resistance group includes a first resistor, a second resistor, a third resistor, a fourth resistor, a fifth resistor and a sixth resistor; the sum of the first resistor and the second resistor is equal to the sum of the third resistor and the fourth resistor; the sum of the third resistor and the fourth resistor is equal to the sum of the fifth resistor and the sixth resistor.

[0010] In an implementation manner of the first aspect, the primary side of the detection circuit may share a group of power supplies.

[0011] In an implementation manner of the first aspect, the vector calculation formula includes:

[0012] U ab =U a -U b

[0013] U bc =U b -U c

[0014] U ca =U c -U a

[0015] Among them, U a Indicates the A phase voltage of the three-phase input PFC; U b Indicates the B-phase voltage of the three-phase input PFC; U c Indicates the C-phase voltage of the three-phase input PFC.

[0016] In the second aspect, the present application provides a three-phase input line voltage detection system, which includes: a neutral point production module, which is used to use equal-resistance resistors in parallel on the motor phase lines at the input end to produce the neutral point of the three-phase input PFC, and the neutral point is equivalent to a virtual N line; the virtual N line is used as the common point of the detection circuit; a detection module, which is used to obtain the three-phase phase voltage of the three-phase input PFC based on the detection circuit; an MCU control module, which is used to perform vector calculation based on the three-phase phase voltage to obtain the line voltage of the three-phase input PFC.

[0017] In the third aspect, the present application provides a three-phase input line voltage detection circuit, 8. The detection circuit includes: a three-phase input equivalent resistance group, a three-phase operational amplifier module, and an MCU module; the three-phase input equivalent resistance group is respectively arranged at the input ends of phase A, phase B, and phase C, and is used to make a virtual three-phase input neutral point at the input end by adopting a star connection method and connecting equal-resistance resistors in parallel, and use it as the common point of the three-way isolated operational amplifier detection circuit; the input end of the three-phase operational amplifier module is connected to one end of the three-phase input equivalent resistance group; the output end of the three-phase operational amplifier module is connected to the MCU module, and is used to calculate through the three-phase phase voltage and line voltage vector operation method to obtain the three-phase line voltage Uab, Ubc, and Uca.

[0018] In an implementation of the third aspect, the three-phase input equivalent resistor group includes: a first resistor, a second resistor, a third resistor, a fourth resistor, a fifth resistor and a sixth resistor; the first resistor and the second resistor are arranged at the A-phase input terminal; the third resistor and the fourth resistor are arranged at the B-phase input terminal; the fifth resistor and the sixth resistor are arranged at the C-phase input terminal;

[0019] in,

[0020] One end of the first resistor is connected to the A-phase power supply terminal, the other end of the first resistor is connected to one end of the second resistor, and the other end of the second resistor is grounded; one end of the third resistor is connected to the B-phase power supply terminal, the other end of the third resistor is connected to one end of the fourth resistor, and the other end of the fourth resistor is grounded; one end of the fifth resistor is connected to the C-phase power supply terminal, the other end of the fifth resistor is connected to one end of the sixth resistor, and the other end of the sixth resistor is grounded;

[0021] The second resistor is connected in parallel with the three-phase operational amplifier module of phase A; the fourth resistor is connected in parallel with the three-phase operational amplifier module of phase B; and the sixth resistor is connected in parallel with the three-phase operational amplifier module of phase C.

[0022] In a fourth aspect, the present application provides an electronic terminal, comprising: a processor and a memory; the memory is used to store a computer program; the processor is connected to the memory, and is used to execute the computer program stored in the memory, so that the electronic device executes the three-phase input line voltage detection method described above.

[0023] As described above, the three-phase input line voltage detection method, detection system and detection circuit described in the present application have the following beneficial effects:

[0024] (1) The present application provides a three-phase input line voltage detection method, which uses a set of DC power supplies to power the isolated operational amplifier, which simplifies the design of the switching power supply; the input line voltage detection method of the present application can detect a larger input voltage (approximately 1.4 times that of the traditional solution). The method provided by the present application has a wide range of applications and high utilization value.

[0025] (2) In this application, a three-phase line neutral point is made, which can be equivalent to a virtual N line, and then a three-way isolation operational amplifier detection circuit is used to detect the three-phase input equivalent phase voltage waveform, and it is input into the MCU control chip after isolation and amplification. Finally, according to the vector relationship between the three-phase line voltage and the phase voltage, the MCU control chip can deduce the three-phase input line voltage. In this application, the number of components is reduced, and the input line voltage can be stably detected, which reduces the cost. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 Display is a single-phase AC waveform under normal conditions.

[0027] Figure 2 The figure shows a three-phase input line voltage detection circuit diagram in the prior art.

[0028] Figure 3 Shown is a flow chart of the three-phase input line voltage detection method described in an embodiment of the present application.

[0029] Figure 4 Shown is a structural diagram of the three-phase input line voltage detection system described in an embodiment of the present application.

[0030] Figure 5 Shown is a structural framework diagram of a three-phase input line voltage detection circuit as described in an embodiment of the present application.

[0031] Figure 6 Shown is a three-phase input line voltage detection circuit diagram described in an embodiment of the present application.

[0032] Figure 7 Shown is a schematic diagram of a virtual N line structure of a three-phase input line voltage detection circuit according to an embodiment of the present application.

[0033] Figure 8 Shown is a vector diagram of the three-phase line voltage and phase voltage of the three-phase input line voltage detection circuit described in an embodiment of the present application.

[0034] Fig. 9 Shown is a schematic diagram of the electronic terminal structure of the three-phase input line voltage detection circuit described in an embodiment of the present application.

[0035] Component number description

[0036] 41 Neutral point production module

[0037] 42 Detection Module

[0038] 43 MCU control module

[0039] 51 Three-phase input equivalent resistance group

[0040] 52 Three-phase operational amplifier module

[0041] 53 MCU module

[0042] 91 Processor

[0043] 92 Memory DETAILED DESCRIPTION

[0044] The following describes the embodiments of the present application through specific examples, and those skilled in the art can easily understand other advantages and effects of the present application from the contents disclosed in this specification. The present application can also be implemented or applied through other different specific embodiments, and the details in this specification can also be modified or changed in various ways based on different viewpoints and applications without departing from the spirit of the present application. It should be noted that the following embodiments and features in the embodiments can be combined with each other without conflict.

[0045] It should be noted that the illustrations provided in the following embodiments are only schematic illustrations of the basic concept of the present application, and thus the drawings only show components related to the present application rather than being drawn according to the number, shape and size of components in actual implementation. In actual implementation, the type, quantity and proportion of each component may be changed at will, and the component layout may also be more complicated.

[0046] The following embodiments of the present application provide a three-phase input line voltage detection method, detection system and detection circuit, by making a three-phase line neutral point, which can be equivalent to a virtual N line, and then through a three-way isolation operational amplifier detection circuit, the three-phase input equivalent phase voltage waveform is detected, and it is input into the MCU control chip after isolation and amplification, and finally according to the vector relationship between the three-phase line voltage and the phase voltage, the MCU control chip can derive the three-phase input line voltage; solve the problem in the prior art that the common-mode input voltage of the isolation operational amplifier is too small and limited because the detection circuit cannot be made into a differential input at the same time as the detection, resulting in the overall hardware complexity of the detection circuit and the difficulty of the switch power supply design. The present application simplifies the design of the switch power supply by using a set of DC power supplies to power the isolation operational amplifier; at the same time, the number of components is reduced, the physical meaning is clearer, and the three-phase input line voltage detection effect is better.

[0047] The three-phase input line voltage detection method provided in the embodiment of the present application will be described in detail below in conjunction with the drawings in the embodiment of the present application.

[0048] See also Figure 3 , which is a flow chart of the three-phase input line voltage detection method described in the embodiment of the present application. Figure 3 As shown, this embodiment provides a three-phase input line voltage detection method.

[0049] The three-phase input line voltage detection method specifically comprises the following steps:

[0050] S1, at the input end, a resistor of equal resistance is connected in parallel to the motor phase line to produce a neutral point of the three-phase input PFC, and the neutral point is equivalent to a virtual N line.

[0051] The S1 comprises the following steps:

[0052] S11, resistors of equal resistance are connected in parallel to the three-phase lines at the input end;

[0053] S12, obtaining the voltage between each phase line and the virtual N line;

[0054] S13, taking the midpoint of each of the equal-resistance resistors connected in parallel as a virtual N line.

[0055] In one embodiment, a virtual three-phase input neutral point is created at the input end by connecting equal-resistance resistors in parallel, and the virtual three-phase input neutral point is used as the common point of the three-way isolation operational amplifier detection circuit.

[0056] Specifically, first, determine the three-phase system parameters: the three-phase system parameters include: any one or more combinations of voltage level, current size, phase relationship, resistance of each phase line, and inductance of each phase line; design the neutral point structure according to requirements; adopt a star structure, and connect the three-phase lines to the neutral point in the neutral point structure respectively; through electrical connection and the three-phase system parameters, the neutral point of the three-phase line is equivalent to a virtual N line.

[0057] S2, using the virtual N line as a common point of the detection circuit.

[0058] S3, obtaining three-phase phase voltages of a three-phase input PFC based on the detection circuit.

[0059] In one embodiment, the voltage on the three-phase input equivalent resistance group in the detection circuit is input into a three-way isolation operational amplifier to obtain the phase voltages Ua, Ub, and Uc of the three-phase input PFC; the phase voltages of the three-phase input PFC are input into the MCU module for processing.

[0060] Specifically, the voltage on the equivalent resistor is detected, and the detected voltage signal is amplified by a three-way isolation operational amplifier circuit to obtain the three-phase voltages Ua, Ub, and Uc, which are then input into the MCU module respectively.

[0061] For example, the three-phase input equivalent resistor group includes: a first resistor R1, a second resistor R3, a third resistor R4, a fourth resistor R6, a fifth resistor R7 and a sixth resistor R9. The sum of the first resistor R1 and the second resistor R3 is equal to the sum of the third resistor R4 and the fourth resistor R6; the sum of the third resistor R4 and the fourth resistor R6 is equal to the sum of the fifth resistor R7 and the sixth resistor R9, that is: R1+R3=R4+R6=R7+R9.

[0062] S4, performing vector calculation based on the three-phase phase voltage to obtain the line voltage of the three-phase input PFC.

[0063] In one embodiment, the MCU module calculates the line voltages Uab, Ubc, and Uca of the three-phase input PFC by a three-phase phase voltage and line voltage vector operation method.

[0064] The vector calculation formula includes:

[0065] U ab =U a -U b

[0066] U bc =U b -U c

[0067] U ca =Uc -U a

[0068] Among them, U a Indicates the A phase voltage of the three-phase input PFC; U b Indicates the B-phase voltage of the three-phase input PFC; U c Indicates the C-phase voltage of the three-phase input PFC.

[0069] The present application provides a three-phase input line voltage detection method, by making a three-phase line neutral point, which can be equivalent to a virtual N line, and then a three-way isolation operational amplifier detection circuit detects the three-phase input equivalent phase voltage waveform, isolates and amplifies it, and then inputs it into the MCU control chip. Finally, according to the vector relationship between the three-phase line voltage and the phase voltage, the MCU control chip can deduce the three-phase input line voltage.

[0070] The protection scope of the three-phase input line voltage detection method described in the embodiment of the present application is not limited to the execution order of the steps listed in the present embodiment. All solutions implemented by adding, reducing or replacing steps in the prior art based on the principles of the present application are included in the protection scope of the present application.

[0071] An embodiment of the present application also provides a three-phase input line voltage detection system, which can implement the three-phase input line voltage detection method described in the present application. However, the implementation device of the three-phase input line voltage detection method described in the present application includes but is not limited to the structure of the three-phase input line voltage detection system listed in the present embodiment. All structural deformations and replacements of the prior art made according to the principles of the present application are included in the protection scope of the present application.

[0072] The three-phase input line voltage detection system provided by this embodiment will be described in detail below with reference to the drawings.

[0073] This embodiment provides a three-phase input line voltage detection system, including:

[0074] See also Figure 4 , which is a structural diagram of the three-phase input line voltage detection system described in the embodiment of the present application. Figure 4 As shown, the three-phase input line voltage detection system includes: a neutral point production module 41, a detection module 42, and an MCU control module 43.

[0075] The neutral point making module 41 is used to use equal resistance resistors connected in parallel to the motor phase lines at the input end to make the neutral point of the three-phase input PFC, and to make the neutral point equivalent to a virtual N line; and to use the virtual N line as the common point of the detection circuit.

[0076] Connect equal-resistance resistors in parallel on the three-phase lines at the input end; obtain the voltage between each phase line and the virtual N line; and use the midpoint of each of the equal-resistance resistors connected in parallel as the virtual N line.

[0077] In one embodiment, a virtual three-phase input neutral point is created at the input end by connecting equal-resistance resistors in parallel, and the virtual three-phase input neutral point is used as the common point of the three-way isolation operational amplifier detection circuit.

[0078] The detection module 42 is used to obtain the three-phase phase voltage of the three-phase input PFC based on the detection circuit.

[0079] In one embodiment, the voltage on the three-phase input equivalent resistance group in the detection circuit is input into a three-way isolation operational amplifier to obtain the phase voltages Ua, Ub, and Uc of the three-phase input PFC; the phase voltages of the three-phase input PFC are input into the MCU module for processing.

[0080] Specifically, the voltage on the equivalent resistor is detected, and the detected voltage signal is amplified by a three-way isolation operational amplifier circuit to obtain the three-phase voltages Ua, Ub, and Uc, which are then input into the MCU module respectively.

[0081] The MCU control module 43 is used to perform vector calculation based on the three-phase phase voltages to obtain the line voltages Uab, Ubc, and Uca of the three-phase input PFC.

[0082] The three-phase input line voltage detection system provided in the embodiment of the present application can implement the three-phase input line voltage detection method described in the present application, but the implementation device of the three-phase input line voltage detection method described in the present application includes but is not limited to the structure of the three-phase input line voltage detection system listed in the present embodiment. All structural deformations and replacements of the prior art made according to the principles of the present application are included in the protection scope of the present application.

[0083] In the several embodiments provided in the present application, it should be understood that the disclosed system, device or method can be implemented in other ways. For example, the device embodiments described above are only schematic. For example, the division of modules / units is only a logical function division. There may be other division methods in actual implementation, such as multiple modules or units can be combined or integrated into another system, or some features can be ignored or not executed. Another point is that the mutual coupling or direct coupling or communication connection shown or discussed can be an indirect coupling or communication connection through some interfaces, devices or modules or units, which can be electrical, mechanical or other forms.

[0084] The modules / units described as separate components may or may not be physically separated, and the components displayed as modules / units may or may not be physical modules, that is, they may be located in one place, or they may be distributed on multiple network units. Some or all of the modules / units may be selected according to actual needs to achieve the purpose of the embodiments of the present application. For example, the functional modules / units in the various embodiments of the present application may be integrated into a startup module, or each module / unit may exist physically separately, or two or more modules / units may be integrated into one module / unit.

[0085] Those of ordinary skill in the art should further appreciate that the units and algorithm steps of each example described in conjunction with the embodiments disclosed herein can be implemented in electronic hardware, computer software, or a combination of the two. In order to clearly illustrate the interchangeability of hardware and software, the composition and steps of each example have been generally described in the above description according to function. Whether these functions are performed in hardware or software depends on the specific application and design constraints of the technical solution. Professional and technical personnel can use different methods to implement the described functions for each specific application, but such implementation should not be considered to be beyond the scope of this application.

[0086] See also Figure 5 and Figure 6 , respectively showing the three-phase input line voltage detection circuit structure framework diagram described in the embodiment of the present application and the three-phase input line voltage detection circuit diagram described in the embodiment of the present application.

[0087] The detection circuit includes: a three-phase input equivalent resistance group 51 , a three-phase operational amplifier module 52 , and an MCU module 53 .

[0088] The three-phase input equivalent resistance group 51 is respectively arranged at the input end of phase A, phase B and phase C, and is used to make a virtual three-phase input neutral point by using a star connection method at the input end using a connection method of equal resistance resistors in parallel, and use it as the common point of the three-way isolation operational amplifier detection circuit. The input end of the three-phase operational amplifier module 52 is connected to one end of the three-phase input equivalent resistance group 51. The output end of the three-phase operational amplifier module 52 is connected to the MCU module 53, and is used to calculate by a three-phase phase voltage and line voltage vector operation method to obtain the three-phase line voltage Uab, Ubc, Uca.

[0089] In this embodiment, the three-phase input equivalent resistor group 51 includes: a first resistor, a second resistor, a third resistor, a fourth resistor, a fifth resistor and a sixth resistor. The first resistor and the second resistor are arranged at the A-phase input terminal; the third resistor and the fourth resistor are arranged at the B-phase input terminal; the fifth resistor and the sixth resistor are arranged at the C-phase input terminal.

[0090] Among them, one end of the first resistor is connected to the A-phase power supply terminal, the other end of the first resistor is connected to one end of the second resistor, and the other end of the second resistor is grounded; one end of the third resistor is connected to the B-phase power supply terminal, the other end of the third resistor is connected to one end of the fourth resistor, and the other end of the fourth resistor is grounded; one end of the fifth resistor is connected to the C-phase power supply terminal, the other end of the fifth resistor is connected to one end of the sixth resistor, and the other end of the sixth resistor is grounded.

[0091] The second resistor is connected in parallel with the three-phase operational amplifier module of phase A; the fourth resistor is connected in parallel with the three-phase operational amplifier module of phase B; and the sixth resistor is connected in parallel with the three-phase operational amplifier module of phase C.

[0092] Specifically, a first resistor R1 and a second resistor R3 are provided at the input end of phase A. One end of the first resistor R1 is connected to the power supply end of phase A, the other end of the first resistor R1 is connected to one end of the second resistor R3, and the other end of the second resistor R3 is grounded; the second resistor is connected in parallel to the three-phase operational amplifier module of phase A. At the same time, the input end of phase A is also connected to the input end of the operational amplifier module of phase A; one end of the output end of the operational amplifier module of phase A is connected to the resistor R2, and the other end is grounded.

[0093] Similarly, a third resistor R4 and a fourth resistor R6 are provided at the input end of phase B. One end of the third resistor R4 is connected to the power supply end of phase B, the other end of the third resistor R4 is connected to one end of the fourth resistor R6, and the other end of the fourth resistor R6 is grounded; the fourth resistor R6 is connected in parallel with the three-phase operational amplifier module of phase B. At the same time, the input end of phase B is also connected to the input end of the operational amplifier module of phase B; one end of the output end of the operational amplifier module of phase B is connected to the resistor R5, and the other end is grounded.

[0094] A fifth resistor R7 and a sixth resistor R9 are provided at the input end of the phase C. One end of the fifth resistor R7 is connected to the power supply end of the phase C, the other end of the fifth resistor R7 is connected to one end of the sixth resistor R9, and the other end of the sixth resistor R9 is grounded; the sixth resistor R9 is connected in parallel with the three-phase operational amplifier module of the phase C. At the same time, the input end of the phase C is also connected to the input end of the operational amplifier module of the phase C; one end of the output end of the operational amplifier module of the phase C is connected to the resistor R2, and the other end is grounded.

[0095] See also Figure 7 and Figure 8 , respectively showing a virtual N line configuration diagram of the three-phase input line voltage detection circuit according to an embodiment of the present application and Figure 8Shown is a vector diagram of the three-phase line voltage and phase voltage of the three-phase input line voltage detection circuit described in an embodiment of the present application.

[0096] From the above, it can be seen that the circuit is a virtual neutral point formed by a connection method composed of 6 resistors as the common point of the three-way isolation operational amplifier detection circuit. Here, the following conditions need to be met, namely:

[0097] R1+R3=R4+R6=R7+R9

[0098] That is to say, the resistance values ​​of each phase input to the neutral point must be equal to make the network N a virtual neutral point of the three-phase input; after the network N becomes the virtual neutral point of the three-phase input, the primary test of the three-way isolation operational amplifier detection circuit can share a set of power supplies to detect the voltages on R3, R6, and R9 respectively, and after isolation and amplification by the isolation operational amplifier, they are input into the MCU to calculate the line voltages Uab, Ubc, and Uca of the three-phase input PFC.

[0099] Finally, after the MCU receives the three-phase input phase voltages Ua, Ub, and Uc, the three-phase line voltages Uab, Ubc, and Uca can be obtained through a simple addition calculation of the above equation.

[0100] In summary, the three-phase input line voltage detection circuit provided by the present application uses a set of DC power supplies to power the isolated operational amplifier, thereby simplifying the design of the switching power supply; at the same time, the number of components in the circuit is reduced, further reducing the cost. Moreover, under the same amplification factor as the traditional solution, the line input line voltage detection of the present solution can detect a larger input voltage (about 1.4 times that of the traditional solution).

[0101] See also Fig. 9 , which is a schematic diagram of the electronic terminal structure of the three-phase input line voltage detection circuit described in the embodiment of the present application. Fig. 9 As shown, this embodiment provides a three-phase input line voltage detection electronic device, which includes: a processor 91 and a memory 92; the memory 92 is used to store computer programs; the processor 91 is connected to the memory 92, and is used to execute the computer program stored in the memory 92, so that the three-phase input line voltage detection electronic device performs the various steps of the three-phase input line voltage detection method as described above.

[0102] Preferably, the memory may include a random access memory (RAM), and may also include a non-volatile memory (non-volatile memory), such as at least one disk memory.

[0103] The above-mentioned processor can be a general-purpose processor, including a central processing unit (CPU), a network processor (NP), etc.; it can also be a digital signal processor (DSP), an application specific integrated circuit (ASIC), a field programmable gate array (FPGA) or other programmable logic devices, discrete gates or transistor logic devices, discrete hardware components.

[0104] In summary, the present application provides a three-phase input line voltage detection method and system, which has the following beneficial effects:

[0105] (1) The present application provides a three-phase input line voltage detection method, which uses a set of DC power supplies to power the isolated operational amplifier, which simplifies the design of the switching power supply; the input line voltage detection method of the present application can detect a larger input voltage (approximately 1.4 times that of the traditional solution). The method provided by the present application has a wide range of applications and high utilization value.

[0106] (2) In this application, a three-phase neutral point is made and equivalent to a virtual N line, and then a three-way isolation operational amplifier detection circuit is used to detect the three-phase input equivalent phase voltage waveform, which is input into the MCU control chip after isolation and amplification. Finally, according to the vector relationship between the three-phase line voltage and the phase voltage, the MCU control chip can deduce the three-phase input line voltage. In this application, while reducing the number of components, the input line voltage can be stably detected, thereby reducing costs. Therefore, this application effectively overcomes the various shortcomings of the prior art and has a high industrial utilization value.

[0107] The above embodiments are merely illustrative of the principles and effects of the present application and are not intended to limit the present application. Anyone familiar with the technology may modify or change the above embodiments without violating the spirit and scope of the present application. Therefore, all equivalent modifications or changes made by a person of ordinary skill in the art without departing from the spirit and technical ideas disclosed in the present application shall still be covered by the claims of the present application.

Claims

1. A three-phase input line voltage detection method, characterized in that: The method comprises: At the input end, a resistor of equal resistance is connected in parallel to the motor phase line to produce a neutral point of the three-phase input PFC, and the neutral point is equivalent to a virtual N line; Using the virtual N line as a common point of the detection circuit; Acquire the three-phase phase voltage of the three-phase input PFC based on the detection circuit; Vector calculation is performed based on the three-phase phase voltages to obtain the line voltages of the three-phase input PFC.

2. The three-phase input line voltage detection method according to claim 1, characterized in that: At the input end, a resistor of equal resistance is connected in parallel to the motor phase line to produce a neutral point of the three-phase input PFC. The neutral point is equivalent to a virtual N line, including: Resistors of equal resistance are connected in parallel on the three-phase lines at the input end; Obtain the voltage between each phase line and the virtual N line; The midpoint of each of the equal-resistance resistors connected in parallel is used as a virtual N line.

3. The three-phase input line voltage detection method according to claim 1, characterized in that: Acquiring the three-phase phase voltage of the three-phase input PFC based on the detection circuit includes: Input the voltage on the three-phase input equivalent resistance group in the detection circuit into a three-way isolation operational amplifier to obtain the phase voltages Ua, Ub, and Uc of the three-phase input PFC; The phase voltage of the three-phase input PFC is input into the MCU module for processing.

4. The three-phase input line voltage detection method according to claim 3, characterized in that: The three-phase input equivalent resistor group includes a first resistor, a second resistor, a third resistor, a fourth resistor, a fifth resistor and a sixth resistor; The sum of the first resistor and the second resistor is equal to the sum of the third resistor and the fourth resistor; The sum of the third resistor and the fourth resistor is equal to the sum of the fifth resistor and the sixth resistor.

5. The three-phase input line voltage detection method according to claim 3, characterized in that: The primary side of the detection circuit can share a set of power supplies.

6. The three-phase input line voltage detection method according to claim 1, characterized in that: The vector calculation formula include: IN ab =U a -IN b IN bc =U b -IN c IN ca =U c -IN a Among them, U a Indicates the A phase voltage of the three-phase input PFC; U b Indicates the B-phase voltage of the three-phase input PFC; U c Indicates the C-phase voltage of the three-phase input PFC.

7. A three-phase input line voltage detection system, characterized in that: include: A neutral point production module is used to use equal resistance resistors connected in parallel to the motor phase line at the input end to produce a neutral point of the three-phase input PFC, and to make the neutral point equivalent to a virtual N line; and to use the virtual N line as a common point of the detection circuit; A detection module, used for obtaining the three-phase phase voltage of the three-phase input PFC based on the detection circuit; The MCU control module is used to perform vector calculation based on the three-phase phase voltage to obtain the line voltage of the three-phase input PFC.

8. A three-phase input line voltage detection circuit, characterized in that: The detection circuit comprises: a three-phase input equivalent resistance group, a three-phase operational amplifier module, and an MCU module; The three-phase input equivalent resistor groups are respectively arranged at the input ends of phase A, phase B and phase C, and are used to make a virtual three-phase input neutral point by using a star connection method to connect equal-resistance resistors in parallel at the input end, and use it as the common point of the three-way isolation operational amplifier detection circuit; The input end of the three-phase operational amplifier module is connected to one end of the three-phase input equivalent resistance group; The output end of the three-phase operational amplifier module is connected to the MCU module, and is used to calculate through a three-phase phase voltage and line voltage vector operation method to obtain the three-phase line voltage Uab, Ubc, and Uca.

9. The three-phase input line voltage detection circuit according to claim 8, characterized in that: The three-phase input equivalent resistor group includes: a first resistor, a second resistor, a third resistor, a fourth resistor, a fifth resistor and a sixth resistor; The first resistor and the second resistor are arranged at the A-phase input terminal; the third resistor and the fourth resistor are arranged at the B-phase input terminal; the fifth resistor and the sixth resistor are arranged at the C-phase input terminal; in, One end of the first resistor is connected to the A-phase power supply terminal, the other end of the first resistor is connected to one end of the second resistor, and the other end of the second resistor is grounded; One end of the third resistor is connected to the B-phase power supply terminal, the other end of the third resistor is connected to one end of the fourth resistor, and the other end of the fourth resistor is grounded; One end of the fifth resistor is connected to the C-phase power supply terminal, the other end of the fifth resistor is connected to one end of the sixth resistor, and the other end of the sixth resistor is grounded; The second resistor is connected in parallel with the three-phase operational amplifier module of phase A; The fourth resistor is connected in parallel with the three-phase operational amplifier module of phase B; The sixth resistor is connected in parallel with the three-phase operational amplifier module of phase C.

10. An electronic terminal, characterized in that: include: Processor and memory; The memory is used to store computer programs; The processor is connected to the memory and is used to execute the computer program stored in the memory so that the three-phase input line voltage detection device executes the three-phase input line voltage detection method according to any one of claims 1 to 6.

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