A frequency converter power supply control circuit and power supply detection method

Abstract

The present application discloses a frequency converter power supply control circuit and a power supply detection method, which belongs to the technical field of frequency converter circuits. In order to solve the technical problem of power supply safety and reliability; the key points of its technical solution are that it includes a switching power supply module, a single-chip microcomputer control circuit, a multi-way power supply circuit and a multi-way power supply detection module, the switching power supply module generates a single first low-voltage DC power supply, the first low-voltage DC power outputs a second stabilized DC power to the main control single-chip microcomputer through a voltage stabilizer, the single-chip microcomputer control circuit completes the internal self-check, controls the operation of the multi-way power supply circuit, the single-chip microcomputer control circuit is connected to the multi-way power supply detection module and the multi-way power supply circuit, the multi-way power supply detection module is also connected to the multi-way power supply circuit, after the multi-way power supply is detected and determined to be normal for each channel, the multi-way power supply circuit outputs power to the frequency converter, which has the effect of improving working reliability and reducing economic costs in case of failure.

Description

Technical Field

[0001] The present application relates to the technical field of inverter circuits, and in particular to an inverter power supply control circuit and a power supply detection method. Background Art

[0002] The inverter used in the water pump needs to use a low-voltage DC power supply for its control circuit. For the inverter with isolated drive, multiple isolated power supplies are required. If these power supplies are abnormal, the inverter will not work or even burn out. Therefore, it is necessary to confirm whether these power supplies are normal.

[0003] Many conventional inverters do not have normal operation confirmation for these circuits. Those that do generally use simple optocoupler detection, which can only indicate that there is power but cannot tell whether the voltage is within the normal range.

[0004] In addition, the power supply used by the inverter is mostly a method of directly outputting multiple power supplies from a switching power supply. Although this method has a simple circuit, it will cause voltage instability. The main reason is that the switching power supply can only perform voltage regulation control according to one of the channels (usually +5V for the microcontroller). When the current of this channel is small, the output voltage of the other channels will be low, especially when loaded. When the current of this channel is large, the output voltage of the other channels will be high, especially when the load is small. This causes large fluctuations in the output of other power supplies.

[0005] In addition, the inverter output part of the inverter should be powered after the MCU output is stable. If the inverter part is powered first, the MCU output will be unstable, which may cause erroneous logic and damage the inverter circuit. Therefore, it is necessary to power the MCU first, and then power the inverter part after the MCU output is stable. Summary of the invention

[0006] In view of the above-mentioned shortcomings (problems) of the prior art, in order to provide a reliable power supply circuit applied to the above-mentioned inverter, the present application provides an inverter power supply control circuit and a power supply detection method.

[0007] To achieve the above objectives and other related objectives, this application adopts the following technical solutions:

[0008] A frequency converter power supply control circuit includes a switching power supply module, a single-chip microcomputer control circuit, a multi-way power supply circuit and a multi-way power supply detection module. The switching power supply module generates a single first low-voltage direct current power supply, and the first low-voltage direct current outputs a second stabilized direct current to a main control microcontroller through a voltage stabilizer.

[0009] After the single chip control circuit completes the internal self-check, it controls the operation of the multi-channel power supply circuit.

[0010] The single chip control circuit is connected to the multi-way power supply detection module and the multi-way power supply circuit. The multi-way power supply detection module is also connected to the multi-way power supply circuit. After the multi-way power supply is detected and it is determined that each way is normal, the multi-way power supply circuit outputs power to the inverter.

[0011] Preferably, the input power of the multi-channel power supply circuit is controlled by a relay circuit, the relay circuit is provided with a control signal by a single-chip control circuit, and each output end of the multi-channel power supply circuit is detected by a multi-channel power supply detection module.

[0012] Preferably, the multi-channel power supply detection module includes a voltage terminal, a digital ground terminal, a feedback terminal, a resistor R1, a resistor R2, a resistor R3, a resistor R4, a resistor R5, a resistor R6, a resistor R7, a resistor R8, a capacitor C1, a capacitor C2, a transistor N1, a transistor N2, a transistor P1, and an optical coupler G1, and the voltage terminal is connected to one end of the resistor R1, one end of the resistor R3 and the transistor P1 The emitter of transistor N1 is connected to the collector of transistor N1 and one end of resistor R2, the other end of resistor R2 is connected to the base of transistor P1, the other end of resistor R3 is connected to one end of capacitor C1, the collector of transistor N2, and the base of transistor N1, the base of transistor N2 is connected to one end of resistor R7 and one end of resistor R6, the other end of resistor R6 is connected to the emitter of transistor N2 and one end of capacitor C2, the collector of transistor P1 is connected to one end of resistor R4, the other end of resistor R4 is connected to the first pin of optocoupler G1, the other end of capacitor C1, the emitter of transistor N2, the other end of resistor R7, the other end of capacitor C2, and the second pin of optocoupler G1 are commonly connected to the digital ground, the third pin of optocoupler G1 is connected to the analog ground, the fourth pin of optocoupler G1 is connected to one end of resistor R5 and one end of resistor R8, the other end of resistor R5 is connected to the second stabilized DC power, and the other end of resistor R8 is the feedback end to provide a feedback signal to the single-chip control circuit.

[0013] A frequency converter power supply detection method is also provided, which adopts the frequency converter power supply control circuit, wherein the single chip microcomputer first completes internal self-checking, and after the single chip microcomputer works normally, it controls the operation of the multi-channel power supply circuit, and the first low-voltage direct current passes through the multi-channel power supply circuit to generate a multi-channel driving voltage for the frequency converter driving part;

[0014] After the switching power supply is stable, each power supply is tested through the multi-power supply detection module. Only when each power supply is normal can the inverter operate normally.

[0015] The detection method of the multi-channel power supply detection module includes: using a voltage-frequency conversion circuit, and transmitting the generated frequency signal to the single-chip microcomputer through an optical coupler.

[0016] Preferably, in the process of the voltage-frequency conversion circuit detecting the frequency of channel i, the single-chip microcomputer first waits for a high level, then waits for a low level to appear and starts timing, then waits for a high level to appear, and finally waits for a low level to appear and stops timing to obtain the period Ti, saves the period Ti into an array, and determines whether N periods have been detected. If N periods have not been detected, the detection cycle continues. If N periods have been detected, the average value of the obtained period values ​​is calculated to obtain the effective period value of channel i.

[0017] In summary, this application at least includes the following beneficial technical effects:

[0018] 1. The power supply and driving process of the inverter are safer, which can avoid equipment failure and economic losses caused by power supply;

[0019] 2. It can realize efficient data collection and detection, greatly improving data processing efficiency and operation efficiency;

[0020] 3. Provides a new power supply solution. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 is a circuit block diagram of an embodiment of the present application;

[0022] Figure 2 is a circuit schematic diagram of an embodiment of the present application;

[0023] Figure 3 It is the schematic diagram of the voltage-frequency conversion circuit in the multi-channel power supply detection module;

[0024] Figure 4 Run the flow chart for the microcontroller;

[0025] Figure 5 This is the specific detection flow chart of the i-th frequency in the single-chip microcomputer.

[0026] Description of main reference numerals:

[0027] 100. Switching power supply module; 200. Single chip microcomputer control circuit; 300. Multi-channel power supply circuit; 400. Multi-channel power supply detection module. DETAILED DESCRIPTION

[0028] 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.

[0029] It should be noted that the illustrations provided in the following embodiments are only schematic illustrations of the basic concept of the present application. The illustrations only show the components related to the present application rather than being drawn according to the number, shape and size of the components in actual implementation. In actual implementation, the type, quantity and proportion of each component can be changed at will, and the component layout type may also be more complicated.

[0030] The specific implementation of the present application is further described below in conjunction with the accompanying drawings.

[0031] The present application embodiment discloses a frequency converter power supply control circuit, referring to Figure 1 and Figure 2 As shown, it includes a switching power supply module 100, a single-chip control circuit 200, a multi-way power supply circuit 300 and a multi-way power supply detection module 400. The input of the switching power supply can be a 220V mains power supply. The switching power supply module 100 generates a single first low-voltage DC power supply, and the first low-voltage DC power is V+. The first low-voltage DC power outputs a second regulated DC power to the main control single-chip computer through a voltage regulator, and the voltage regulator is Figure 2 IC2, wherein the capacitor C is used to eliminate voltage fluctuations. The second regulated DC power is VCC. The single-chip microcomputer control circuit 200 includes a single-chip microcomputer IC1. Of course, this single-chip microcomputer IC1 is used as a main control single-chip microcomputer.

[0032] The single chip control circuit 200 is connected to the multi-way power supply detection module 400 and the multi-way power supply circuit 300. The multi-way power supply detection module 400 is also connected to the multi-way power supply circuit 300. After the multi-way power supply is detected and it is determined that each way is normal, the multi-way power supply circuit 300 outputs power to the inverter.

[0033] Specifically, the input power of the multi-way power supply circuit 300 is controlled by a relay circuit, the single chip control circuit 200 provides a control signal to the relay circuit, and each output end of the multi-way power supply circuit 300 is detected by a multi-way power supply detection module 400 .

[0034] After the single-chip control circuit 200 completes the internal self-test, it controls the operation of the multi-channel power supply circuit 300. The operation of the multi-channel power supply circuit 300 is controlled by outputting a control signal RLY1 of a relay using the IO6 pin of the single-chip IC1. The first low-voltage direct current V+ is provided to the multi-channel power supply circuit 300 through the relay circuit, specifically to the multi-channel isolation DCDC module U2, and it can be seen that U2 outputs 5 channels of direct current, including: one channel VDD1, VSS1; two channels VDD2, VSS2; three channels VDD3, VSS3; four channels VDD4, VSS4; five channels VDD5, VSS5.

[0035] Each path is detected by the multi-path power detection module 400U3 to form five feedback signals: FREQ1, FREQ2, FREQ3, FREQ4, and FREQ5. All paths are provided to the input and output pins of the microcontroller IC1. The operating voltage of the microcontroller IC1 is VCC.

[0036] Specifically, refer to Figure 3 As shown, the multi-channel power supply detection module 400 includes a detection circuit for one channel, namely, a voltage-frequency conversion circuit.

[0037] The voltage-frequency conversion circuit includes a voltage terminal, a digital ground terminal, a feedback terminal, a resistor R1, a resistor R2, a resistor R3, a resistor R4, a resistor R5, a resistor R6, a resistor R7, a resistor R8, a capacitor C1, a capacitor C2, a transistor N1, a transistor N2, a transistor P1, and an optical coupler G1. The voltage terminal is connected to one end of the resistor R1, one end of the resistor R3 and the transistor P1. The emitter of transistor N1 is connected to the collector of transistor N1 and one end of resistor R2, the other end of resistor R2 is connected to the base of transistor P1, the other end of resistor R3 is connected to one end of capacitor C1, the collector of transistor N2, and the base of transistor N1, the base of transistor N2 is connected to one end of resistor R7 and one end of resistor R6, the other end of resistor R6 is connected to the emitter of transistor N2 and one end of capacitor C2, the collector of transistor P1 is connected to one end of resistor R4, the other end of resistor R4 is connected to the first pin of optocoupler G1, the other end of capacitor C1, the emitter of transistor N2, the other end of resistor R7, the other end of capacitor C2, and the second pin of optocoupler G1 are commonly connected to the digital ground, the third pin of optocoupler G1 is connected to the analog ground, the fourth pin of optocoupler G1 is connected to one end of resistor R5 and one end of resistor R8, the other end of resistor R5 is connected to the second stabilized DC power, and the other end of resistor R8 is the feedback end to provide a feedback signal to the single-chip control circuit 200.

[0038] Working principle description: This circuit converts the VDD1 voltage signal into a frequency signal related to the voltage, isolates it through the optocoupler G1, and transmits it to the microcontroller. The microcontroller can detect the frequency and determine whether the power supply voltage value is within the normal range.

[0039] Its working principle is: VDD1 charges C1 through R3. When charged to the point where N1 is turned on, N2 is also turned on, and C1 is discharged. After C1 is discharged, N1 is turned off. At this time, the capacitor C2 will keep N2 turned on for a period of time, and then N2 is turned off. After N2 is turned off, VDD1 continues to charge C1 through R3, and this is repeated, generating a pulse signal of a certain frequency.

[0040] This frequency is related to the size of VDD1. The larger the VDD1 is, the easier it is for C1 to charge to the voltage at which N1 turns on. At the same time, the charging voltage given to C2 by N1 when it turns on is also higher, and the discharge time of C2 is also longer. Therefore, the longer N2 remains on, thus generating a frequency signal related to the size of the VDD1 voltage.

[0041] When N1 is turned on, P1 will also be turned on, the light-emitting end of the optocoupler G1 will emit light, the light-receiving end will be turned on, and FREQ1 will be low level. When N1 is turned off, P1 will also be turned off, the light-emitting end of G1 will not emit light, the light-receiving end will be turned off, and FREQ1 will be high level, thus generating an output signal with the same frequency as the input. Example 2:

[0042] A frequency converter power supply detection method, based on the above embodiment 1, adopts the above frequency converter power supply control circuit, and combines Figure 4 and Figure 5 As shown, the single-chip microcomputer first completes an internal self-check. After the single-chip microcomputer works normally, it controls the multi-way power supply circuit 300 to operate, and the first low-voltage direct current generates a multi-way driving voltage for the inverter driving part through the multi-way power supply circuit 300; after the switching power supply is stable, each power supply is detected by the multi-way power supply detection module 400. Only when each power supply is normal can the inverter operate normally; the detection method of the multi-way power supply detection module 400 includes: using a voltage-frequency conversion circuit, and the generated frequency signal is transmitted to the single-chip microcomputer through an optical coupler.

[0043] There are several steps:

[0044] 1. After the microcontroller is powered on and completes the internal self-test, the control relay K1 is turned on to supply power to the multi-channel power supply circuit 300.

[0045] 2. After a delay, when the output of the multi-channel power supply circuit 300 is stable, the single-chip microcomputer starts to detect the frequency signal of each channel of power supply. If the frequency is within the normal range, it means that the power supply is normal, and then the next channel is detected.

[0046] 3. After all the outputs of the multi-channel power supply circuit 300 have been tested and found to be normal, frequency conversion output can be performed. Otherwise, an alarm will be sounded to inform the user of power supply abnormality.

[0047] 4. The detection method of frequency signal is as follows:

[0048] By adjusting the appropriate parameters, the frequency does not need to be too high (in practical applications, several hundred Hz is generally selected). Although the output voltages of multiple power supplies are different, the parameters can be adjusted so that the frequency of each channel is within the same range, because the voltage of each channel is clearly known.

[0049] The microcontroller starts timing when it detects a low level and stops timing when it encounters the next low level. The length of time obtained is the period of the signal of the detected frequency. Several period values ​​can be measured and averaged to calculate the frequency.

[0050] In practical applications, the period value is usually used directly for judgment. Figure 5 As shown, in the process of the voltage-frequency conversion circuit detecting the frequency of channel i, the single-chip microcomputer first waits for a high level, then waits for a low level to start timing, then waits for a high level, and finally waits for a low level to stop timing, and obtains the period Ti, saves the period Ti into an array, and determines whether N periods have been detected. If N periods have not been detected, the detection cycle continues. If N periods have been detected, the average value of the obtained period values ​​is calculated to obtain the effective period value of channel i.

[0051] The above embodiments are only 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, any equivalent changes made based on the structure, shape, and principle of the present application shall be included in the protection scope of the present application.

Claims

1. A frequency converter power supply control circuit, comprising a switching power supply module (100), a single-chip microcomputer control circuit (200), a multi-channel power supply circuit (300) and a multi-channel power supply detection module (400), wherein the switching power supply module (100) generates a single first low-voltage direct current power supply, and the first low-voltage direct current outputs a second stabilized direct current to a main control microcontroller through a voltage stabilizer, It is characterized in that After the single chip control circuit completes the internal self-check, it controls the multi-channel power supply circuit (300) to operate. The single-chip control circuit (200) is connected to a multi-channel power supply detection module (400) and a multi-channel power supply circuit (300), and the multi-channel power supply detection module (400) is also connected to the multi-channel power supply circuit (300). After the multi-channel power supply is detected and it is determined that each channel is normal, the multi-channel power supply circuit (300) outputs power to the inverter; the input power of the multi-channel power supply circuit (300) is controlled by a relay circuit, and the relay circuit is provided with a control signal by the single-chip control circuit (200). Each output end of a power supply circuit (300) is detected by a multi-way power supply detection module (400); the multi-way power supply detection module (400) comprises a voltage end, a digital ground end, a feedback end, a resistor R1, a resistor R2, a resistor R3, a resistor R4, a resistor R5, a resistor R6, a resistor R7, a resistor R8, a capacitor C1, a capacitor C2, a transistor N1, a transistor N2, a transistor P1, and an optical coupler G1, the voltage end being connected to one end of the resistor R1, one end of the resistor R3 and the transistor P1 The emitter of transistor N1 is connected to the other end of resistor R1, the other end of resistor R2 is connected to the base of transistor P1, the other end of resistor R3 is connected to one end of capacitor C1, the collector of transistor N2, and the base of transistor N1, the base of transistor N2 is connected to one end of resistor R7 and one end of resistor R6, the other end of resistor R6 is connected to the emitter of transistor N2 and one end of capacitor C2, the collector of transistor P1 is connected to one end of resistor R4, and resistor The other end of R4 is connected to the first pin of the optocoupler G1, the other end of the capacitor C1, the emitter of the transistor N2, the other end of the resistor R7, the other end of the capacitor C2, and the second pin of the optocoupler G1 are commonly connected to the digital ground, the third pin of the optocoupler G1 is connected to the analog ground, the fourth pin of the optocoupler G1 is connected to one end of the resistor R5 and one end of the resistor R8, the other end of the resistor R5 is connected to the second regulated DC power, and the other end of the resistor R8 is a feedback end that provides a feedback signal to the single-chip control circuit (200).

2. A method for detecting power supply of a frequency converter, characterized in that: The inverter power supply control circuit as claimed in claim 1 is adopted, the single chip microcomputer first completes an internal self-check, and after the single chip microcomputer works normally, the multi-channel power supply circuit (300) is controlled to operate, and the first low-voltage direct current is used to generate a multi-channel driving voltage for the inverter driving part through the multi-channel power supply circuit (300); After the switching power supply is stable, each power supply is detected by a multi-power supply detection module (400). Only when each power supply is normal can the inverter operate normally. The detection method of the multi-channel power supply detection module (400) comprises: using a voltage-frequency conversion circuit, and transmitting the generated frequency signal to a single-chip microcomputer through an optical coupler.

3. A method for detecting power supply of a frequency converter according to claim 2, characterized in that: In the process of the voltage-frequency conversion circuit detecting the frequency of channel i, the single-chip microcomputer first waits for a high level, then waits for a low level to start timing, then waits for a high level, and finally waits for a low level to stop timing, and obtains the period Ti. The period Ti is saved in an array to determine whether N periods have been detected. If N periods have not been detected, the detection cycle continues. If N periods have been detected, the average value of the obtained period values ​​is calculated to obtain the effective period value of channel i.

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