CN219392160U - Driving phase current sampling circuit, fault detection circuit and direct current fan - Google Patents

Abstract

The utility model provides a driving phase current sampling circuit, a fault detection circuit and a direct current fan, wherein the circuit comprises an IPM module, a current detection module and an operational amplifier circuit module; the IPM module comprises a U, V, W phase current output pin and NU, NV and NW phase current negative terminal pins; the current sampling resistor is connected between the NU phase current negative terminal pin and the ground, and between the NV phase current negative terminal pin and the ground; the signal input end of the first operational amplifier circuit is connected between the NU phase current negative terminal pin and the current sampling resistor, and the signal input end of the second operational amplifier circuit is connected between the NV phase current negative terminal pin and the current sampling resistor; the signal output ends of the first operational amplifier circuit and the second operational amplifier circuit are connected to the processing element, the two-phase current is detected U, V by adopting the double-resistance sampling circuit and the operational amplifier circuit, and the W-phase current is obtained through calculation, so that the number of components is reduced, the complexity of the circuit is reduced, and the reliability and the efficiency are improved.

Description

Drive phase current sampling circuit, fault detection circuit and DC fan

technical field

The utility model relates to the technical field of current detection, in particular to a driving phase current sampling circuit, a fault detection circuit and a DC fan.

Background technique

The existing DC fan circuit phase current sampling generally uses a three-resistor sampling circuit to detect the three-phase current. The three-resistance sampling circuit requires three sets of sampling resistors and three operational amplifier circuits. There are many components, complex circuits, and low reliability and efficiency.

Utility model content

In order to solve the above problems, the utility model provides a driving phase current sampling circuit, including an IPM module, a current detection module and an operational amplifier circuit module; the IPM module includes U, V, W phase current output pins and NU, NV, NW phase current negative terminal pins; the current detection circuit module includes two current sampling resistors, and each of the current sampling resistors is connected between the NU phase current negative terminal pin and the ground, and between the NV phase current negative terminal pin and the ground; the operational amplifier circuit module includes a first operational amplifier circuit and a second operational amplifier circuit; The signal input end of the first operational amplifier circuit is connected between the negative terminal pin of the NU phase current and the current sampling resistor, and the signal input end of the second operational amplifier circuit is connected between the negative terminal pin of the NV phase current current and the current sampling resistor; the signal output terminals of the first operational amplifier circuit and the second operational amplifier circuit are connected to the processing element, so that the processing element detects the U and V two-phase currents, and calculates the W phase current.

The driving phase current sampling circuit provided by the embodiment of the utility model adopts a dual-resistor sampling circuit and an operational amplifier circuit to detect U and V two-phase currents, and the W-phase current is obtained through calculation, thereby reducing the number of components, reducing circuit complexity, and improving reliability and efficiency.

Optionally, a voltage detection module is also included; the voltage detection module includes two voltage sampling resistors, and the voltage sampling resistors are connected in parallel with the current sampling resistors.

The embodiment of the utility model is based on the voltage sampling resistor. When the IPM module works normally, the voltage at both ends of the voltage sampling resistor is detected, so as to obtain U and V two-phase voltages.

Optionally, a hardware overcurrent protection circuit is also included; the sampling terminal of the hardware overcurrent protection circuit is connected between the current sampling resistor and ground, and the output terminal of the hardware overcurrent protection circuit is connected to the hardware protection pin of the IPM module.

The embodiment of the utility model is also provided with a hardware overcurrent protection circuit, so as to play the role of IPM module hardware overcurrent protection.

Optionally, a program overcurrent protection circuit is also included; the input terminal of the program overcurrent protection circuit is connected to the fault output pin of the IPM module, and the output terminal of the program overcurrent protection circuit is connected to the controller for outputting a fault signal to the controller.

The embodiment of the utility model also includes a program overcurrent protection circuit, so as to achieve the function of overcurrent protection.

Optionally, the current detection module further includes a first resistor and a second resistor connected in parallel; the first resistor and the second resistor are connected between the current sampling resistor and the ground.

The embodiment of the utility model is also provided with a first resistor and a second resistor, which can play a role of current limiting protection.

Optionally, the IPM module further includes three sets of bootstrap capacitors; each set of bootstrap capacitors is respectively connected between the U, V, W phase current output pins and the corresponding U, V, W phase IGBT-driven high-end auxiliary power supply pins.

The embodiment of the utility model is also provided with a bootstrap circuit, so as to realize voltage bootstrap.

Optionally, the U, V, and W phase current output pins are all connected to a wire-to-board connector.

The embodiment of the utility model is also provided with a wire-to-board connector for connection with fans, compressors, etc., and plays the role of supplying power to the above-mentioned equipment.

Optionally, the first operational amplifier circuit and the second operational amplifier circuit respectively include comparators.

In the embodiment of the utility model, the operational amplifier function is realized through the comparator and related circuits.

The utility model provides a fault detection circuit, which includes the above-mentioned driving phase current sampling circuit and the processing element, and controls the IPM module to stop working when the three-phase current output by the processing element exceeds a threshold.

The utility model provides a DC blower, which includes the above-mentioned fault detection circuit.

The fault detection circuit and the DC blower provided by the utility model can achieve the same technical effect as the above-mentioned driving phase current sampling circuit.

Description of drawings

Fig. 1 is a schematic structural diagram of an IPM module and a current and voltage detection module for driving a phase current sampling circuit provided by an embodiment of the present invention;

Fig. 2 is a schematic structural diagram of a bootstrap circuit of an IPM module driving a phase current sampling circuit provided by an embodiment of the present invention;

FIG. 3 is a schematic structural diagram of an operational amplifier circuit for driving a phase current sampling circuit provided by an embodiment of the present invention.

Detailed ways

In order to make the above purpose, features and advantages of the utility model more obvious and easy to understand, the specific embodiments of the utility model will be described in detail below in conjunction with the accompanying drawings.

Aiming at the problem that the existing three-resistor sampling circuit has too many components and complex circuits, a dual-resistor sampling circuit is designed to sample UV two-phase current through two sets of sampling resistors. The sampling circuit includes an IPM module, two sampling resistors and two operational amplifier circuits. The current is not detected when the IPM module is started, and the voltage at both ends of the sampling resistor is detected during normal operation, and the U and V two-phase currents are detected through the operational amplifier circuit. The W-phase current is obtained by calculation (the sum of the three-phase currents is zero). In addition, there are hardware over-current protection and program over-current protection. This solution has accurate phase current sampling, fewer components and improved efficiency.

The embodiment of the present invention provides a driving phase current sampling circuit, including an IPM (Intelligent Power Module, intelligent power module) module, a current detection module and an operational amplifier circuit module. The driving phase current sampling circuit is used to collect the operating status of fans and compressors (including normal operation, locked rotor, and lack of phase status). When an abnormally large current is detected, a trigger signal is sent to the control chip, and the control chip turns off the signal driving the IPM module. The above-mentioned fans and compressors stop running, thereby achieving the purpose of overcurrent protection.

Among them, the IPM module is suitable for frequency converters for driving motors and various inverter power supplies, and is an ideal power electronic device for frequency conversion household appliances. Specifically, the IPM module includes U, V, W phase current output pins and NU, NV, NW phase current negative terminal pins. The U, V, and W phase current output pins are three-phase current outputs, and are used to supply power to DC fans and DC compressors.

The above-mentioned current detection circuit module includes two current sampling resistors, and each current sampling resistor is respectively connected between the negative terminal pin of the NU phase current and the ground, and between the negative terminal pin of the NV phase current and the ground. The current sampling resistor is a resistor connected in series with a small resistance. In this embodiment, only U and V two-phase currents can be detected, so as to realize the purpose of circuit simplification and cost reduction.

The operational amplifier circuit module includes a first operational amplifier circuit and a second operational amplifier circuit. Specifically, the signal input terminal of the first operational amplifier circuit is connected between the NU phase current negative terminal pin and the current sampling resistor, and the signal input terminal of the second operational amplifier circuit is connected between the NV phase current negative terminal pin and the current sampling resistor;

Both the signal output ends of the first operational amplifier circuit and the second operational amplifier circuit are connected to the processing element, so that the processing element detects U and V phase currents and calculates the W phase current.

The driving phase current sampling circuit provided by the embodiment of the utility model adopts a dual-resistor sampling circuit and an operational amplifier circuit to detect U and V two-phase currents, and the W-phase current is obtained through calculation, thereby reducing the number of components, reducing circuit complexity, and improving reliability and efficiency.

As a feasible manner, the above-mentioned driving phase current sampling circuit further includes a voltage detection module; the voltage detection module includes two voltage sampling resistors, and the voltage sampling resistors are connected in parallel with the above-mentioned current sampling resistors. The voltage sampling resistor is a resistor connected in parallel with a large resistance value. Based on the voltage sampling resistor, the IPM module detects the voltage at both ends of the voltage sampling resistor when it is working normally, thereby detecting the U and V phase voltages.

As a feasible way, the above-mentioned driving phase current sampling circuit also includes a hardware overcurrent protection circuit; the sampling terminal of the hardware overcurrent protection circuit is connected between the current sampling resistor and the ground, and the output terminal of the hardware overcurrent protection circuit is connected with the hardware protection pin (CSC) of the IPM module. The hardware protection pin of the IPM module, when the input voltage of the pin is greater than the threshold, the IPM module will stop working. For example, a small non-inductive resistor can be connected to the hardware overcurrent protection circuit. If the current of a certain phase is greater than the threshold value, the voltage of this phase is greater than the threshold value. When it is applied to the CSC pin, the IPM module stops working, thereby playing the role of IPM module hardware overcurrent protection.

As a feasible way, the above-mentioned drive phase current sampling circuit also includes a program overcurrent protection circuit; the input terminal of the program overcurrent protection circuit is connected to the fault output pin (FO) of the IPM module, and the output terminal of the program overcurrent protection circuit is connected to the controller for outputting a fault signal to the controller. If there is a fault, the FO pin outputs a low-level signal, which is transmitted to the single-chip microcomputer through the over-current protection circuit of the above program, and the single-chip microcomputer turns off the 6-way control signal driving the IPM module, and the IPM module stops running, thereby achieving the function of over-current protection.

As a feasible manner, the above-mentioned current detection module further includes a first resistor and a second resistor connected in parallel; the first resistor and the second resistor are connected between the current sampling resistor and the ground. The above-mentioned first resistor and second resistor can play a role of current limiting protection.

As a feasible way, the above-mentioned IPM module also includes three sets of bootstrap capacitors; each set of bootstrap capacitors is respectively connected between the U, V, W phase current output pins and the corresponding U, V, W phase IGBT-driven high-end auxiliary power supply pins. The above 6 pins are connected with 3 sets of bootstrap capacitors. Voltage bootstrap is to use the circuit itself to generate a higher voltage than the input voltage.

As a feasible way, the U, V, and W phase current output pins are all connected to a wire-to-board connector, and the wire-to-board connector can be connected to a fan, a compressor, etc., and play a role in supplying power to the above-mentioned equipment.

Optionally, the first operational amplifier circuit and the second operational amplifier circuit respectively include a comparator, and the operational amplifier function is mainly realized through the comparator and related circuits.

Exemplarily, FIG. 1 shows a schematic structural diagram of an IPM module and a current and voltage detection module for driving a phase current sampling circuit provided by an embodiment of the present invention. Figure 1 shows that the IPM module includes U, V, W phase current output pins, NU, NV, NW phase current negative terminal pins, VBU, VBV, VBW phase IGBT-driven high-end auxiliary power supply pins, DC input positive terminal pin P (310V), power supply pin VCCW (15V), hardware protection pin CSC, and fault output pin FO.

Among them, the NU and NV pins are connected with a sampling resistor, and are grounded after passing through a protective resistor. An access point of a detection circuit is arranged at the sampling resistor to detect current and voltage. As shown in Figure 1, it includes resistors R108, R43, R109, R46, R57 and R110. The CSC pin is connected to the output of the above-mentioned NU and NV pins through a hardware overcurrent protection circuit, including resistors R185, R102 and capacitor C50. The FO pin is connected to the program overcurrent protection circuit, including resistors R100, R104 and capacitors C99, C52, and the output terminal F-FO is connected to the controller.

Fig. 2 shows a schematic structural diagram of a bootstrap circuit of an IPM module driving a phase current sampling circuit provided by an embodiment of the present invention. Pin VBU and pin U are connected to electrolytic capacitor E17 and capacitor C89, VBV and pin V are connected to electrolytic capacitor E18 and capacitor C90, VBW and pin W are connected to electrolytic capacitor E19 and capacitor C91. FIG. 2 also shows that the U, V, and W phase current output pins are all connected to the wire-to-board connector DC-M.

Fig. 3 shows a schematic structural diagram of an operational amplifier circuit for driving a phase current sampling circuit provided by an embodiment of the present invention. Figure 3 shows the operational amplifier circuits corresponding to the U and V phase currents, including comparators U71 and U7B, resistors R112, R113, R115, R116, R117, R118, R119, R120, R121, R122, R123, R124 and capacitors C63 and C64.

In the above circuit, the IPM module works with a power supply voltage of 15VDC and a control voltage of 310VDC. When the IPM module is started, the bootstrap capacitors E17, E18, and E19 are charged, the starting current of the fan passes through R57, R110 to the ground, and the output voltage of the operational amplifier circuit FIV-AD, FIU-AD is a relatively high level of about 3.2V. At this time, the program does not collect the output of the operational amplifier. After entering normal operation, control the on-off of the upper and lower bridges of U, V, and W through software, collect the voltages at FIV and FIU respectively, and amplify them through the op-amp circuit (R121, R122 provide a 1.65V reference), and the output voltages FIV-AD and FIU-AD of the op-amp are sent to the single-chip microcomputer for processing and control, and detect the U and V two-phase currents. The W-phase current is obtained by calculation (the sum of the three-phase currents is zero). SC is the hardware overcurrent protection. F-FO is the working status detection of the IPM module.

The above-mentioned circuit provided in this embodiment can detect whether the DC fan circuit is faulty; it can be applied to scenarios where DC fans and DC compressors are used; the phase current sampling of this circuit is accurate, the components are reduced, the cost is reduced, and the production efficiency is improved.

This embodiment realizes the detection of the working current of the DC fan, and can effectively judge whether the DC fan and the driving current are faulty; the above-mentioned dual-resistor sampling circuit reduces circuit complexity and improves reliability; a comparator-based DC fan fault detection circuit is provided.

The embodiment of the utility model also provides a fault detection circuit, which includes the above-mentioned drive phase current sampling circuit and a processing element, and controls the IPM module to stop working when the three-phase current output by the processing element exceeds a threshold.

The embodiment of the utility model also provides a DC blower, including the above-mentioned fault detection circuit.

Of course, those skilled in the art can understand that all or part of the processes in the methods of the above-mentioned embodiments can be implemented through a computer program to instruct the control device. The program can be stored in a computer-readable storage medium, and the program can include the processes of the above-mentioned method embodiments when executed, wherein the storage medium can be a memory, a magnetic disk, an optical disk, etc.

Although the utility model is disclosed as above, the utility model is not limited thereto. Any person skilled in the art can make various changes and modifications without departing from the spirit and scope of the present utility model, so the protection scope of the present utility model should be based on the scope defined in the claims.

Finally, it should also be noted that in this document, relational terms such as first and second etc. are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the term "comprises", "comprises" or any other variation thereof is intended to cover a non-exclusive inclusion such that a process, method, article or apparatus comprising a set of elements includes not only those elements but also other elements not expressly listed or which are inherent to such process, method, article or apparatus. Without further limitations, an element defined by the phrase "comprising a ..." does not exclude the presence of additional identical elements in the process, method, article or apparatus comprising said element.

Although the utility model is disclosed as above, the utility model is not limited thereto. Any person skilled in the art can make various changes and modifications without departing from the spirit and scope of the present utility model, so the protection scope of the present utility model should be based on the scope defined in the claims.

Claims (10)

1. A drive phase current sampling circuit, characterized in that, comprises an IPM module, a current detection module and an operational amplifier circuit module; The IPM module includes U, V, W phase current output pins and NU, NV, NW phase current negative terminal pins; The current detection module includes two current sampling resistors, each of the current sampling resistors is respectively connected between the NU phase current negative terminal pin and the ground, and between the NV phase current negative terminal pin and the ground; the operational amplifier circuit module includes a first operational amplifier circuit and a second operational amplifier circuit; the signal input terminal of the first operational amplifier circuit is connected between the NU phase current negative terminal pin and the current sampling resistor, and the signal input terminal of the second operational amplifier circuit is connected between the NV phase current negative terminal pin and the current sampling resistor; Both the signal output terminals of the first operational amplifier circuit and the second operational amplifier circuit are connected to the processing element, so that the processing element detects U and V two-phase currents and calculates the W-phase current. 2. The driving phase current sampling circuit according to claim 1, further comprising a voltage detection module; The voltage detection module includes two voltage sampling resistors, and the voltage sampling resistors are connected in parallel with the current sampling resistors. 3. The driving phase current sampling circuit according to claim 1, further comprising a hardware overcurrent protection circuit; The sampling terminal of the hardware overcurrent protection circuit is connected between the current sampling resistor and ground, and the output terminal of the hardware overcurrent protection circuit is connected with the hardware protection pin of the IPM module. 4. The driving phase current sampling circuit according to claim 1, further comprising a program overcurrent protection circuit; The input terminal of the program overcurrent protection circuit is connected to the fault output pin of the IPM module, and the output terminal of the program overcurrent protection circuit is connected to the controller for outputting a fault signal to the controller. 5. The driving phase current sampling circuit according to any one of claims 1-4, wherein the current detection module further comprises a first resistor and a second resistor connected in parallel; the first resistor and the second resistor are connected between the current sampling resistor and the ground. 6. The drive phase current sampling circuit according to any one of claims 1-4, wherein the IPM module also includes three groups of bootstrap capacitors; the bootstrap capacitors of each group are respectively connected between the high-end auxiliary power supply pins driven by the U, V, and W phase current output pins and the corresponding U, V, and W phase IGBTs. 7. The driving phase current sampling circuit according to any one of claims 1-4, wherein the U, V, W phase current output pins are all connected to a wire-to-board connector. 8. The driving phase current sampling circuit according to any one of claims 1-4, wherein the first operational amplifier circuit and the second operational amplifier circuit respectively comprise comparators. 9. A fault detection circuit, characterized in that it comprises the driving phase current sampling circuit and the processing element according to any one of claims 1-8, and controls the IPM module to stop working when the three-phase current output by the processing element exceeds a threshold. 10. A DC blower, characterized by comprising the fault detection circuit according to claim 9.