Detection circuit and detection system

Abstract

The utility model provides a detection circuit and a detection system which are applied to the technical field of power electronics, the detection circuit is used for testing a current sensor in an inverter, the detection circuit comprises a main control circuit and the inverter, the inverter comprises two or more inverter bridge arms, and the main control circuit is connected with the inverter bridge arms. Each inverter bridge arm comprises a first power switch device and a second power switch device which are connected in series, the input end of the inverter is connected with a detection power source, and the current sensor is connected with the first power switch device of one inverter bridge arm in parallel. The main control circuit is connected with the control ends of the first power switch device and the second power switch device of each inverter bridge arm, controls the first power switch device connected with the current sensor in parallel to be switched off and controls one of the second power switch devices to be switched on, so that the current sensor is communicated with a detection power supply, and the detection power supply is switched off. The inverter is used for converting electric energy of the detection power supply into current, detection current is provided for the current sensor, and the accuracy of a detection result is effectively improved.

Description

Technical Field

[0001] The present application relates to the field of power electronics technology, and in particular to a detection circuit and a detection system for testing a current sensor in a frequency converter. Background Art

[0002] Current sensors are commonly used core components in frequency converters. In order to verify the function and reliability of the frequency converter, key indicators such as output linearity, output delay and dynamic response of the current sensor need to be verified and tested before it leaves the factory or during daily maintenance to further improve the reliability of the frequency converter.

[0003] In practical applications, providing current to the current sensor and comparing the difference between the current waveform of the current and the response waveform of the current sensor in response to the current is the main way to detect the current sensor. However, due to the large range of the current sensor, it is difficult for the existing technology to provide a stable current that meets the range requirements, resulting in low accuracy of the detection results of the current sensor, which is difficult to meet the detection needs. Utility Model Content

[0004] In view of this, the present application is committed to providing a detection circuit and a detection system for testing the current sensor in the inverter, providing the detection current to the current sensor through the internal circuit of the inverter, and utilizing the reliability of the inverter itself to ensure that the current meets the range requirements and is sufficiently stable and accurate, thereby effectively improving the accuracy of the detection results and meeting the detection requirements.

[0005] In a first aspect, the present application provides a detection circuit for testing a current sensor in a frequency converter, the detection circuit comprising: a main control circuit and an inverter, the inverter comprising two or more inverter bridge arms, each inverter bridge arm comprising a first power switch device and a second power switch device connected in series, wherein:

[0006] The input end of the inverter is connected to a detection power supply;

[0007] The current sensor is connected in parallel with a first power switch device of an inverter bridge arm; and,

[0008] The main control circuit is respectively connected to the control ends of the first power switch device and the second power switch device of each inverter bridge arm, and is configured to: when the current sensor is tested, control the first power switch device connected in parallel with the current sensor to be turned off, and control one of the second power switch devices in the inverter to be turned on, so that the current sensor is connected to the detection power supply to form a closed loop.

[0009] In an optional implementation, the detection circuit provided in the first aspect of the present application further includes: an energy storage circuit, wherein:

[0010] The energy storage circuit is connected in parallel with the input terminal of the inverter;

[0011] The energy storage circuit stores electrical energy when the current sensor is not tested, and releases the stored electrical energy when the current sensor is tested.

[0012] In an optional implementation, the detection circuit provided in the first aspect of the present application further includes: a commutation circuit, wherein:

[0013] The commutation circuit is connected in series with the current sensor and is used for switching the direction in which the current enters the current sensor.

[0014] In an optional implementation, the detection circuit provided in the first aspect of the present application further includes: a regulating circuit, wherein:

[0015] The regulating circuit is connected in series with the current sensor and is used to regulate the amplitude of the current flowing through the current sensor.

[0016] In an optional implementation, the main control circuit includes: a working power supply, a control component and a drive circuit, wherein:

[0017] The input end of the working power supply is connected to the input end of the inverter, and the output end of the working power supply is connected to the control component and the drive circuit respectively;

[0018] The control component is connected to the control end of the drive circuit;

[0019] The output end of the driving circuit serves as the output end of the main control circuit, and is used to output a control signal for controlling the first and second power switch devices to be turned on or off.

[0020] In an optional implementation, the control component includes a main controller, a communication module and a host computer, wherein:

[0021] The host computer is connected to the main controller through the communication module;

[0022] The host computer is used to send a control instruction to the main controller, and the control instruction is used to instruct the drive circuit to output a control signal for controlling the on or off of the first power switch device and the second power switch device.

[0023] In an optional implementation, the inverter further includes an overcurrent protection circuit, wherein:

[0024] The overcurrent protection circuit is used to output a protection signal when the operating current of the inverter is greater than a preset current threshold, and the protection signal is used to control the drive circuit to control the corresponding inverter bridge arm to shut down.

[0025] In a second aspect, the present application provides a detection system for testing a current sensor in a frequency converter, the detection system comprising:

[0026] DC detection power supply;

[0027] A capacitor connected in parallel with the DC detection power supply;

[0028] An inverter, whose input end is connected to the DC detection power supply and comprises two or more inverter bridge arms, each inverter bridge arm comprises a first power switch device and a second power switch device connected in series, and the current sensor is connected in parallel with the first power switch device of one inverter bridge arm;

[0029] A driving circuit, used for driving the first power switch device and the second power switch device of the inverter to turn off or on;

[0030] The host computer is used to provide instructions to the drive circuit through the communication module. When testing the current sensor, the host computer controls the first power switch device connected in parallel with the current sensor to be turned off, and controls one of the second power switch devices in the inverter to be turned on, so that the current sensor is connected to the detection power supply to form a closed loop.

[0031] In an optional embodiment, the detection system provided in the second aspect of the present application further includes: a waveform detection device, connected to the current sensor, for displaying the current waveform of the current and the response waveform of the current sensor in response to the current.

[0032] Based on the above content, the detection circuit provided in the present application is used to test the current sensor in the inverter. The detection circuit includes a main control circuit and an inverter. The inverter includes two or more inverter bridge arms, each inverter bridge arm includes a first power switch device and a second power switch device connected in series, the input end of the inverter is connected to the detection power supply, the current sensor is connected in parallel with the first power switch device of one inverter bridge arm, and the main control circuit is respectively connected to the control end of the first power switch device and the second power switch device of each inverter bridge arm. When testing the current sensor, the main control circuit controls the first power switch device connected in parallel with the current sensor to turn off, and controls one of the second power switch devices in the inverter to turn on, so that the current sensor is connected to the detection power supply to form a closed loop, thereby using the inverter to convert the electric energy of the detection power supply into current. Since the inverter has good current output performance, the output current fluctuation is small and the current amplitude is large, which can meet the detection requirements of the current sensor. Therefore, the detection circuit provided in the present application can provide the current sensor with a current that meets the detection requirements, effectively improving the accuracy of the detection result. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] In order to more clearly illustrate the embodiments of the utility model or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the utility model. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0034] Figure 1 It is a structural block diagram of a detection circuit provided by an embodiment of the utility model.

[0035] Figure 2 It is a structural block diagram of another detection circuit provided by an embodiment of the utility model.

[0036] Figure 3 This is a schematic diagram of a current sensor connection method provided by an embodiment of the utility model.

[0037] Figure 4 This is a structural block diagram of another detection circuit provided by an embodiment of the utility model.

[0038] Figure 5 This is a structural block diagram of another detection circuit provided by an embodiment of the utility model. DETAILED DESCRIPTION

[0039] The following will be combined with the drawings in the embodiments of the present application to clearly and completely describe the technical solutions in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of this application.

[0040] As mentioned earlier, current sensors are commonly used core components in frequency converters. In order to verify the function and reliability of the frequency converter, key indicators such as output linearity, output delay and dynamic response of the current sensor need to be verified and tested before the frequency converter leaves the factory or during daily maintenance to further improve the reliability of the frequency converter.

[0041] Currently, the main method of detecting current sensors is to input current into the current sensor and compare the difference between the current waveform of the current and the response waveform of the current sensor in response to the current. However, for current sensors with a larger range, the required current is also larger. Most of the detection equipment in the prior art is difficult to provide a stable current that meets the range requirements, resulting in low accuracy of the detection results of the current sensor, which is difficult to meet the detection needs.

[0042] To solve the above problems, the present application provides a detection circuit, which is mainly used to test the current sensor in the frequency converter. The detection circuit mainly utilizes the circuits in the frequency converter, such as the main control circuit and the inverter, to convert the direct current input to the frequency converter into a large current signal. Since the frequency converter itself has a reliable protection circuit, the inverter has good current output performance, the output current fluctuation is small and the current amplitude is large, which can meet the detection requirements of the current sensor. Therefore, the detection circuit provided by the present application can provide the current sensor with a current that meets the detection requirements, effectively improving the accuracy of the detection results.

[0043] Based on the above, see Figure 1 , Figure 1 is a structural block diagram of a detection circuit provided in the present application. The detection circuit provided in this embodiment includes a main control circuit 10 and an inverter 20 .

[0044] First of all, it should be noted that in the detection circuit provided in each embodiment of the present application, the inverter 20 includes two or more inverter bridge arms. Combining the implementation method of the inverter in the related technology, it can be known that in actual applications, the inverter 20 can include two inverter bridge arms or three inverter bridge arms. In the subsequent content, the detection circuit provided in each embodiment of the present application is explained by taking the inverter including three inverter bridge arms as an example.

[0045] Combination Figure 1 As shown, the inverter 20 includes three inverter bridge arms connected in parallel, each of which includes a first power switch device and a second power switch device connected in series, and the first power switch device and the second power switch device are usually implemented by selecting the same type of power switch tube, such as an IGBT tube. Figure 1 In the embodiment, the switch tubes Q1 and Q2 connected in series serve as the first inverter bridge arm of the inverter 20, the switch tube Q1 is the upper bridge arm, and the switch tube Q2 is the lower bridge arm; the switch tubes Q3 and Q4 connected in series serve as the second inverter bridge arm of the inverter 20, the switch tube Q3 is the upper bridge arm, and the switch tube Q4 is the lower bridge arm; the switch tubes Q5 and Q6 connected in series serve as the third inverter bridge arm of the inverter 20, the switch tube Q5 is the upper bridge arm, and the switch tube Q6 is the lower bridge arm. Both ends of the first inverter bridge arm serve as the input ends of the inverter 20.

[0046] It should be noted that the first power switch device mentioned in the present application can be a switch tube of the upper bridge arm or a switch tube of the lower bridge arm. Correspondingly, the second power switch device is another switch tube other than the first power switch device in the inverter bridge arm.

[0047] Based on this, the first power switch device of any of the above-mentioned inverter bridge arms is connected in parallel with the current sensor to be measured. Figure 1In the illustrated embodiment, the upper bridge arm of the third inverter bridge arm, namely the switch tube Q5 , is connected in parallel to the current sensor 40 as a first power switch device.

[0048] The output end of the detection power supply 30 is connected to the input end of the inverter 20 to provide direct current to the inverter 20. Further, the main control circuit 10 is respectively connected to the control end of the upper bridge arm and the lower bridge arm of each inverter bridge arm in the inverter 20, that is, respectively connected to the control end of the first power switch device and the second power switch device of each inverter bridge arm. In the present application, the main control circuit 10 can control any upper and lower bridge arms of any inverter bridge arm to be turned on or off.

[0049] Combination Figure 1 As shown, when the current sensor 40 is tested, the main control circuit 10 controls the first power switch device connected in parallel with the current sensor 40, that is, the switch tube Q5 to be turned off, and at the same time, controls the second power switch device in the same inverter bridge arm, that is, the switch tube Q6 to be turned on. The current sensor 40 is connected to the detection power supply 30 through the switch tube Q6 to form a closed loop, and the current flows through the current sensor 40, so that the detection personnel can further complete the detection of the current sensor 40. Furthermore, the main control circuit 10 controls the first inverter bridge arm and the second inverter bridge arm to be turned off to prevent the first inverter bridge arm or the second inverter bridge arm from short-circuiting the detection power supply 30. Combined with Figure 1 As shown, when controlling the first inverter bridge arm to turn off, the main control circuit 10 can control at least one of the switch tubes Q1 and Q2 to turn off. Correspondingly, when controlling the second inverter bridge arm to turn off, the main control circuit 10 can control at least one of the switch tubes Q3 and Q4 to turn off.

[0050] It should be noted that Figure 1 In the detection circuit provided in the embodiment shown, the inverter bridge arms of the inverter are connected in parallel, and the midpoints of the bridge arms are not electrically connected. In another embodiment, in order to provide a more stable DC to the subsequent circuit, the midpoints of the bridge arms of the inverter are connected to each other. For details, see Figure 2 As shown, Figure 2 The N point shown is the neutral point obtained by connecting the midpoints of the bridge arms.

[0051] In Application Figure 2When the detection circuit provided in the illustrated embodiment tests the current sensor 40, the main control circuit 10 controls the first power switch device in the third inverter bridge arm connected in parallel with the current sensor 40, that is, the switch tube Q5 to be turned off. At the same time, since the midpoints of the bridge arms of each inverter bridge arm are connected to each other, the main control circuit 10 controls each second power switch device, that is, one of the switch tubes Q2, Q4 and Q6 to be turned on. Of course, the switch tubes Q1 and Q3 must also be turned off at the same time, thereby ensuring that a unique closed loop is formed between the current sensor 40 and the detection power supply 30, so that the current flows through the current sensor 40 to test the current sensor 40.

[0052] It should be noted that in Figure 2 In the detection circuit provided by the illustrated embodiment, since the midpoints of the bridge arms of each inverter bridge arm are connected to each other, when the current sensor is tested, the conduction state of each power switch device can exist in a variety of combinations, which can be specifically implemented with reference to the aforementioned content and will not be listed here one by one. However, no matter which combination is adopted, it is premised on forming a unique closed loop between the current sensor and the detection power supply to provide current for the current sensor. Without exceeding the core idea of ​​this application, each optional combination belongs to the scope of protection of this application.

[0053] To sum up, the detection circuit provided in this embodiment can use an inverter to convert the electrical energy of the detection power supply into current. Since the inverter has good current output performance, the output current fluctuation is small and the current amplitude is large, which can meet the detection requirements of the current sensor. Therefore, the detection circuit provided in this application can provide the current sensor with a current that meets the detection requirements, thereby effectively improving the accuracy of the detection results.

[0054] Compared with the method of purchasing constant current source equipment to provide current in the prior art, the detection circuit provided in the present application has lower cost, and the detection circuit can be built using the existing circuit design of the inverter at the production site or the frequency converter to be tested, which is convenient and fast, effectively reducing the detection cost of the current sensor and improving the detection efficiency.

[0055] For further information, see Figure 3 , Figure 3 is a structural block diagram of another detection circuit provided in an embodiment of the present application. Figure 1 On the basis of the illustrated embodiment, the detection circuit provided in this embodiment further includes: an energy storage circuit, a commutation circuit 50 and a regulating circuit 60 .

[0056] Specifically, the energy storage circuit is connected in parallel with the input end of the inverter 20. When the current sensor 40 is not tested, the energy storage circuit stores the electric energy provided by the detection power supply 30. Correspondingly, when the current sensor 40 is tested, the energy storage circuit releases the stored electric energy.

[0057] As an optional implementation, Figure 3 In the illustrated embodiment, the energy storage circuit includes a capacitor C1. Figure 3 As shown, the capacitor C1 is connected in parallel with the input end of the inverter 20, that is, connected in parallel with the output end of the detection power supply 30. It can be understood that when the switch tube Q6 is turned off, the aforementioned closed loop cannot be formed, the detection power supply 30 charges the capacitor C1, and the capacitor C1 stores electrical energy; when the switch tube Q6 is turned on, the aforementioned closed loop is formed, and the capacitor C1 and the detection power supply 30 jointly output current to the current sensor 40.

[0058] It can be seen that the energy storage circuit can cooperate with the detection power supply 30 when testing the current sensor 40, and input current to the current sensor 40 at the same time. By utilizing the electric energy stored in the energy storage circuit, the detection circuit provided in this embodiment can provide a larger current, thereby realizing the detection of a large-range current sensor, and further improving the detection capability of the detection circuit provided in this application.

[0059] Furthermore, the detection circuit provided in this embodiment also includes a commutation circuit 50, which is connected in series with the current sensor 40 to form a first series branch. The commutation circuit 50 can switch the direction of the current entering the current sensor 40, thereby realizing the detection of the bidirectional current performance of the current sensor 40.

[0060] As an optional implementation, the commutation circuit 50 provided in this embodiment includes a switch K1, a switch K2, a switch K3 and a switch K4. Figure 3 As shown, any switch includes two connecting paths. Taking switch K1 as an example, when the first connecting terminal 1 is connected to the second connecting terminal 2, a first connecting path is formed. Correspondingly, when the first connecting terminal 1 is connected to the third connecting terminal 3, a second connecting path is formed.

[0061] Specifically, the first connection terminal 1 of the switch K1 serves as the first connection terminal of the commutation circuit 50, and is connected to an output terminal of the inverter 20 (i.e., the connection point of the switch tube Q1, the switch tube Q2, and the switch tube Q3), the second connection terminal 2 of the switch K1 is connected to the second connection terminal 2 of the switch K3, and the third connection terminal 3 of the switch K1 is connected to the second connection terminal 2 of the switch K2. Further, the first connection terminal 1 of the switch K2 serves as the second connection terminal of the commutation circuit 50, and is used to connect the current sensor 40, and the third connection terminal 3 of the switch K2 is connected to the second connection terminal of the switch K4. The first connection terminal 1 of the switch K3 serves as the third connection terminal of the commutation circuit 50, and is used to connect the current sensor 40, and the third connection terminal 3 of the switch tube K3 is connected to the third connection terminal 3 of the switch K4. The first connection terminal 1 of the switch K4 serves as the fourth connection terminal of the commutation circuit 50, and is connected to the midpoint of the bridge arm of the inverter bridge arm, that is, connected to the connection point of the switch tube Q5 and the switch tube Q6.

[0062] Based on the connection relationship, the first connection terminal 1 of the switch K1 is connected to the second connection terminal 2 of the switch K1 itself, the first connection terminal 1 of the switch K3 is also connected to the second connection terminal 2 of the switch K3 itself, the first connection terminal 1 of the switch K2 is connected to the third connection terminal 3 of the switch K2 itself, and the first connection terminal 1 of the switch K4 is connected to the second connection terminal 2 of the switch K4 itself, so as to obtain the following: Figure 2 The first communication path shown allows current to enter the current sensor 40 in a first direction.

[0063] For further information, see Figure 4 As shown, the first connection terminal 1 of switch K1 is connected to the third connection terminal 3 of switch K1 itself, the first connection terminal 1 of switch K2 is connected to the second connection terminal 2 of switch K2 itself, the first connection terminal 1 of switch K3 is connected to the third connection terminal 3 of switch K3 itself, and the first connection terminal 1 of switch K4 is connected to the third connection terminal 3 of switch K4, so that a second connection path can be obtained, so that the current enters the current sensor 40 in the second direction.

[0064] It can be seen that, by applying the detection circuit provided in this embodiment, the detection personnel do not need to remove the current sensor 40 and manually switch the connection mode of the current sensor 40 during the detection process. The direction of the current entering the current sensor 40 can be switched through the commutation circuit 50, thereby realizing bidirectional current detection of the current sensor 40. On the premise of fully utilizing the performance of the current sensor, it also helps to improve the detection efficiency of the current sensor.

[0065] like Figure 3 As shown, the detection circuit provided in this embodiment also includes an adjustment circuit 60. The adjustment circuit 60 is connected in series with the aforementioned first series branch to form a second series branch. In the present application, the adjustment circuit 60 is mainly used to adjust the current amplitude of the current according to actual detection requirements, such as the range of the current sensor 40. In an optional embodiment, the adjustment circuit 60 includes an adjustable resistor. It can be understood that by adjusting the specific resistance value of the adjustable resistor, the current amplitude of the current can be changed, so that the detection circuit provided in the present application can meet the detection requirements of current sensors of different ranges.

[0066] In a possible implementation, the main control circuit may also be connected to the control end of the detection power supply. The main control circuit adjusts the output voltage of the detection power supply and, when used in conjunction with the aforementioned adjustable resistor, can adjust the current amplitude more flexibly and with finer granularity.

[0067] To sum up, based on the foregoing embodiments, the detection circuit provided in this embodiment can provide a larger current through the energy storage circuit, thereby meeting the testing requirements of a large-range current sensor. The direction of the current entering the current sensor can be switched through the commutation circuit, thereby realizing the detection of the bidirectional current performance of the current sensor. Furthermore, the current can be adjusted by adjusting the circuit to meet the detection requirements of current sensors of different ranges.

[0068] Further, based on any of the above embodiments, the present application provides another detection circuit, see Figure 5 As shown ( Figure 5 The embodiment shown in Figure 1 Based on the embodiment shown in the figure), this embodiment provides an optional implementation method of a main control circuit.

[0069] In this embodiment, the main control circuit 10 includes a working power supply 110, a control component 120 and a drive circuit 130. As an optional implementation, the control component 120 provided in this embodiment includes a host computer 1201, a communication module 1202 and a main controller 1203.

[0070] Combination Figure 4 As shown, the input end of the working power supply 110 is connected to the input end of the inverter 20, that is, connected to the output end of the detection power supply 30, and the output end of the working power supply 110 is respectively connected to the drive circuit 130 and the control component 120, specifically, connected to the main controller 1203 in the control component 120. The working power supply 110 is mainly used to convert the output voltage of the detection power supply 30 into a working voltage that meets the working requirements of the drive circuit 130 and the main controller 1203, and provide power for the normal operation of the drive circuit 130 and the main controller 1203.

[0071] The main controller 1203 in the control component 120 is connected to the control end of the drive circuit 130, and the output end of the drive circuit 130 is used as the output end of the main control circuit 10, and is respectively connected to the control end of each bridge arm in the inverter 20. The drive circuit 130 is used to output a control signal that can change the conduction state of the bridge arm, thereby controlling the bridge arm to be turned on or off.

[0072] Furthermore, the host computer 1201 is connected to the main controller 1203 through the communication module 1202. The host computer 1201 is operated by the inspection personnel to send a control instruction to the main controller 1203. The main controller 1203 responds to the control instruction and controls the drive circuit 130 to output a control signal for switching the on or off state of each first power switch device and each second power switch device in the inverter 20.

[0073] In actual applications, the host computer 1201 includes multiple implementation methods, which can be a personal computer, a tablet computer, or an industrial computer used in industrial sites. Of course, it can also be other electronic devices that can communicate with the main controller 1203 and send control instructions to the main controller 1203. They are not listed here one by one. As long as they do not exceed the core idea of ​​this application, they also fall within the scope of protection of this application.

[0074] The specific selection of the communication module 1202 is related to the selection of the host computer 1201 and the communication method between the host computer 1201 and the main controller 1203. In practical applications, it can be either a wired communication module or a wireless communication module. Any communication module that can establish a communication connection between the host computer 1201 and the main controller 130 is optional and also falls within the scope of protection of this application.

[0075] In an optional embodiment, the main controller 1203 can be a controller of the frequency converter or inverter 20 itself. With this configuration, the detection circuit component provided in this embodiment can utilize part of the circuit of the inverter 20 (i.e., the inverter bridge arm), and can also utilize the inverter's own controller to implement the above-mentioned control process, which helps to further reduce the overall cost of the detection circuit.

[0076] In another optional implementation, the main controller 1203 may also be another controller independent of the inverter 20. In this case, the main controller 1203 may adopt Figure 5 The circuit structure shown controls the conduction state of the corresponding power switch device based on the control instruction of the host computer 1201. Of course, the control function of the host computer 1201 can also be integrated to independently control the conduction state of the corresponding power switch device, which is also optional and also falls within the scope of protection of this application.

[0077] It should be noted that no matter which of the above methods is adopted to control the conduction state of the power switch device, the control logic inside the main controller and the host computer is implemented based on relevant technologies, and this application does not limit this.

[0078] It should also be noted that in actual applications, the frequency converter itself includes both the main controller and the current sensor mentioned in the above content. In the production process of the frequency converter, it is naturally necessary to test the current sensor of the frequency converter. Based on this, the current sensor in the frequency converter to be tested can be connected to the detection circuit provided by any of the above embodiments, and the host computer sends a control instruction to the controller of the inverter in the detection circuit through the communication module, thereby completing the detection of the current sensor. With such a setting, the hardware resources at the production site of the frequency converter manufacturer can be fully utilized, and the current sensor can be detected without the need to purchase the detection equipment of the current sensor separately, effectively reducing the detection cost of the current sensor.

[0079] In the detection circuit provided in any of the above embodiments, the inverter of the detection circuit is also provided with an overcurrent protection circuit, which outputs a protection signal when the working current of the inverter is greater than a preset current threshold, and controls the drive circuit to control the corresponding inverter bridge arm to shut down. It can be seen that by building a detection circuit with an inverter, not only can the good current output performance of the inverter be utilized to provide the current sensor with a current with small current fluctuation and large current amplitude to meet the detection requirements of the current sensor, but also the detection circuit and the current sensor can be prevented from being damaged by overcurrent, which helps to improve the service life of the detection circuit and the safety of the detection process of the current sensor to be tested.

[0080] Further, there is a technical solution in the related art that uses a relay to control the discharge of the energy storage capacitor to provide current. This solution cannot control the switching time of the relay, and the switching instantaneous impedance state of the relay is unstable. Accordingly, the waveform of the generated current is also unstable, and it is only suitable for short-circuit current testing that does not require the waveform. In the detection circuit provided by any of the above embodiments of the present application, the main control circuit can also control the on-time and off-time of each power switch device in the corresponding inverter bridge arm. For example, the first power switch device connected in parallel with the current sensor can be controlled to be in the on-state within 50μs, and accordingly, one of the second power switch devices in the inverter is controlled to be in the off-state within 50μs. It can be understood that the control of the on-time and off-time of the power switch device is essentially the control of the time duration of providing current to the current sensor. Based on this, accurate control of the current sensor detection process can be achieved, which is crucial to improving the reliability and effectiveness of the detection results. Moreover, compared with the technical solution of using relays to control the current output process in the related technology, the waveform width of the control signal of the main control circuit is controllable and the waveform quality is higher, which helps to improve the control accuracy of the bridge arm conduction time and shutdown time.

[0081] It should be noted that in the above embodiments, the testing of a single current sensor is used as an example. In actual applications, a current sensor can be connected in parallel to the first power switch device of each inverter bridge arm, so as to realize the simultaneous detection of multiple current sensors, thereby effectively improving the overall detection efficiency.

[0082] Furthermore, the present application also provides a detection system for testing a current sensor in an inverter. The detection system provided in this embodiment includes:

[0083] DC detection power supply;

[0084] A capacitor is connected in parallel with the DC detection power supply;

[0085] An inverter, the input end of which is connected to a DC detection power supply, and includes two or more inverter bridge arms, each of which includes a first power switch device and a second power switch device connected in series, and a current sensor is connected in parallel to the first power switch device of one inverter bridge arm;

[0086] A driving circuit, used for driving the first power switch device and the second power switch device of the inverter to turn off or on;

[0087] The upper computer is used to provide instructions to the drive circuit through the communication module. When testing the current sensor, it controls the first power switch device connected in parallel with the current sensor to be turned off, and controls one of the second power switch devices in the inverter to be turned on, so that the current sensor is connected to the detection power supply to form a closed loop.

[0088] In an optional implementation, the detection system provided in this embodiment further includes a waveform detection device, wherein:

[0089] The waveform detection device is connected to the current sensor. In this embodiment, the waveform detection device is mainly used to display the current waveform of the current and the response waveform of the current sensor in response to the current after the current flows through the current sensor.

[0090] In practical applications, by comparing the differences between the aforementioned current waveform and the response waveform, testers can detect key indicators such as the rated current peak working state, output linearity, output delay, and dynamic response of the current sensor.

[0091] Those skilled in the art will appreciate that the contents disclosed in this disclosure may be subject to various modifications and improvements. For example, the various devices or components described above may be implemented by hardware, or by software, firmware, or a combination of some or all of the three.

[0092] In addition, although the present disclosure makes various references to certain units in the system according to embodiments of the present disclosure, any number of different units can be used and run on the client and / or server. The units are only illustrative, and different aspects of the system and method can use different units.

[0093] Unless otherwise defined, all terms used herein have the same meaning as commonly understood by those of ordinary skill in the art to which the present disclosure belongs. It should also be understood that terms such as those defined in common dictionaries should be interpreted as having a meaning consistent with their meaning in the context of the relevant technology, and should not be interpreted in an idealized or highly formal sense, unless explicitly defined as such herein.

[0094] The above is an explanation of the present disclosure and should not be considered as a limitation thereof. Although several exemplary embodiments of the present disclosure are described, it will be readily understood by those skilled in the art that many modifications may be made to the exemplary embodiments without departing from the novel teachings and advantages of the present disclosure. Therefore, all such modifications are intended to be included within the scope of the present disclosure as defined in the claims. It should be understood that the above is an explanation of the present disclosure and should not be considered to be limited to the specific embodiments disclosed, and modifications to the disclosed embodiments and other embodiments are intended to be included within the scope of the appended claims. The present disclosure is defined by the claims and their equivalents.

Claims

1. A detection circuit for testing a current sensor in a frequency converter, characterized in that: include: A main control circuit and an inverter, wherein the inverter comprises two or more inverter bridge arms, each inverter bridge arm comprises a first power switch device and a second power switch device connected in series, wherein: The input end of the inverter is connected to a detection power supply; The current sensor is connected in parallel with a first power switch device of an inverter bridge arm; and, The main control circuit is respectively connected to the control ends of the first power switch device and the second power switch device of each inverter bridge arm, and is configured to: when the current sensor is tested, control the first power switch device connected in parallel with the current sensor to be turned off, and control one of the second power switch devices in the inverter to be turned on, so that the current sensor is connected to the detection power supply to form a closed loop.

2. The detection circuit according to claim 1, characterized in that: Also includes: Tank circuit, where The energy storage circuit is connected in parallel with the input terminal of the inverter; The energy storage circuit stores electrical energy when the current sensor is not tested, and releases the stored electrical energy when the current sensor is tested.

3. The detection circuit according to claim 1, characterized in that: Also includes: Commutation circuit, where The commutation circuit is connected in series with the current sensor and is used for switching the direction in which the current enters the current sensor.

4. The detection circuit according to claim 1, characterized in that: Also includes: Regulation circuit, where The regulating circuit is connected in series with the current sensor and is used to regulate the amplitude of the current flowing through the current sensor.

5. The detection circuit according to any one of claims 1 to 4, characterized in that: The main control circuit includes: a working power supply, a control component and a drive circuit, wherein: The input end of the working power supply is connected to the input end of the inverter, and the output end of the working power supply is connected to the control component and the drive circuit respectively; The control component is connected to the control end of the drive circuit; The output end of the driving circuit serves as the output end of the main control circuit, and is used to output a control signal for controlling the first and second power switch devices to be turned on or off.

6. The detection circuit according to claim 5, characterized in that: The control component includes a main controller, a communication module and a host computer, wherein: The host computer is connected to the main controller through the communication module; The host computer is used to send a control instruction to the main controller, and the control instruction is used to instruct the drive circuit to output a control signal for controlling the on or off of the first power switch device and the second power switch device.

7. The detection circuit according to claim 5, characterized in that: The inverter also includes an overcurrent protection circuit, wherein: The overcurrent protection circuit is used to output a protection signal when the operating current of the inverter is greater than a preset current threshold, and the protection signal is used to control the drive circuit to control the corresponding inverter bridge arm to shut down.

8. A detection system for testing a current sensor in a frequency converter, characterized in that: include: DC detection power supply; A capacitor connected in parallel with the DC detection power supply; An inverter, whose input end is connected to the DC detection power supply and comprises two or more inverter bridge arms, each inverter bridge arm comprises a first power switch device and a second power switch device connected in series, and the current sensor is connected in parallel with the first power switch device of one inverter bridge arm; A driving circuit, used for driving the first power switch device and the second power switch device of the inverter to turn off or on; The host computer is used to provide instructions to the drive circuit through the communication module. When testing the current sensor, the host computer controls the first power switch device connected in parallel with the current sensor to be turned off, and controls one of the second power switch devices in the inverter to be turned on, so that the current sensor is connected to the DC detection power supply to form a closed loop.

9. The detection system according to claim 8, characterized in that: Also includes: A waveform detection device is connected to the current sensor and is used to display the current waveform of the current and the response waveform of the current sensor in response to the current.

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