Current detection circuit and method of power device, automobile compressor and vehicle

Abstract

The invention relates to the technical field of current detection of power devices, and discloses a current detection circuit and method of a power device, an automobile compressor and a vehicle, the circuit comprises a current power device unit, the input end of the current power device unit is connected with a power device to be detected and a voltage supply power source, the current power device unit and the to-be-detected power device are synchronously driven; the input end of the current sampling unit is connected with the output end of the current power device unit, and the current sampling unit is used for collecting the detection voltage of the current power device unit in a synchronous driving state; and the detection chip is connected with the output end of the current sampling unit, and the detection chip is used for carrying out current detection on the to-be-detected power device based on the detection voltage and a preset overcurrent proportion. According to the invention, the current detection accuracy of the power device is improved.

Description

Technical Field

[0001] This invention relates to the field of current detection technology for power devices, and more particularly to a current detection circuit, method, automotive compressor, and vehicle for power devices. Background Technology

[0002] With the rapid development of power devices such as MOSFETs (Metal-Oxide-Semiconductor Field-Effect Transistors), users have also put forward higher requirements for the current detection methods of high-current power devices.

[0003] Traditional current sensing methods for high-current power devices involve connecting a high-power sampling resistor in series with the device under test (the high-current power device). The current is calculated by reading the voltage drop across the resistor. However, this method has a significant drawback: as the detection current increases, the high-power sampling resistor may break down abnormally. In other words, this method can lead to low accuracy in current sensing due to the large current value causing the high-power sampling resistor to fail.

[0004] The above content is only used to help understand the technical solution of this application and does not represent an admission that the above content is prior art. Summary of the Invention

[0005] The main objective of this invention is to provide a current detection circuit, method, automotive compressor, and vehicle for power devices, aiming to solve the technical problem of low accuracy in current detection of power devices.

[0006] To achieve the above objectives, the present invention provides a current detection circuit for a power device, the current detection circuit for the power device comprising:

[0007] A current power device unit, wherein the input terminal of the current power device unit is connected to the power device under test and the power supply, wherein the current power device unit and the power device under test are driven synchronously;

[0008] A current sampling unit, wherein the input terminal of the current sampling unit is connected to the output terminal of the current power device unit, and the current sampling unit is used to collect the detection voltage of the current power device unit under the synchronous drive state;

[0009] A detection chip is connected to the output terminal of the current sampling unit. The detection chip is used to detect the current of the power device under test based on the detection voltage and a preset overcurrent ratio.

[0010] In one embodiment, the current power device unit includes:

[0011] A sampling power device, wherein the drain of the sampling power device is connected to the drain of the power device under test and the power supply, the gate of the sampling power device is connected to the gate of the power device under test and the output terminal of an external driver, and the source of the sampling power device is connected to the current sampling unit.

[0012] In one embodiment, the current sampling unit includes:

[0013] A sampling resistor, wherein the first end of the sampling resistor is connected to the sampling power device in the current power device unit, and the second end of the sampling resistor is grounded;

[0014] An operational amplifier subunit is provided, wherein the input terminal of the operational amplifier subunit is connected to the first terminal and the second terminal of the sampling resistor, and the output terminal of the operational amplifier subunit is connected to the detection chip.

[0015] A first resistor, the first end of which is connected to the output terminal of the operational amplifier subunit;

[0016] A first capacitor, the first terminal of which is connected to the second terminal of the first resistor, and the second terminal of the first capacitor is grounded.

[0017] In one embodiment, the operational amplification subunit includes:

[0018] A second resistor, the first end of which is connected to the first end of the sampling resistor;

[0019] A third resistor, wherein the first end of the third resistor is connected to the second end of the sampling resistor;

[0020] An operational amplifier, wherein the first input terminal of the operational amplifier is connected to the second terminal of the second resistor, the second input terminal of the operational amplifier is connected to the second terminal of the third resistor, and the output terminal of the operational amplifier is connected to the first terminal of the first resistor and the detection chip;

[0021] A fourth resistor, the first end of which is connected to the first input terminal of the operational amplifier, and the first end of which is connected to the output terminal of the operational amplifier.

[0022] In one embodiment, the current detection circuit of the power device further includes:

[0023] A voltage comparator, wherein the first input terminal of the voltage comparator is connected to the output terminal of the operational amplifier in the current sampling unit, the second input terminal of the voltage comparator is connected to an external voltage source, and the output terminal of the voltage comparator is connected to the enable terminal of an external driver.

[0024] In one embodiment, the detection chip includes:

[0025] A current calculation subunit is provided, the input of which is connected to the output of the operational amplifier in the current sampling unit. The current calculation subunit is used to perform current detection on the power device under test based on the detection voltage and a preset overcurrent ratio.

[0026] A current protection subunit is connected to the input terminal of the current calculation subunit and the enable terminal of the external driver. The current protection subunit is used to provide current protection for the power device under test based on the detected voltage.

[0027] Furthermore, to achieve the above objectives, the present invention also provides a current detection method for a power device, wherein the current detection method for the power device is applied to the current detection circuit of the power device, and the current detection method for the power device includes the following steps:

[0028] Under the state of synchronous driving of the current power device unit and the power device under test, the current sampling unit acquires the detection voltage of the current power device unit;

[0029] The current of the power device under test is detected based on the detection voltage and the preset overcurrent ratio.

[0030] In one embodiment, the step of detecting the current of the power device under test based on the detection voltage and a preset overcurrent ratio includes:

[0031] The actual voltage value corresponding to the detection voltage is determined based on a preset overcurrent ratio, and the current value corresponding to the actual voltage value is also determined.

[0032] The current value is used as the current of the power device under test.

[0033] In one embodiment, after the step of performing current detection on the power device under test based on the detection voltage and a preset overcurrent ratio, the method further includes:

[0034] When the detected voltage is greater than the input voltage of the external voltage source, the voltage comparator in the current detection circuit of the power device outputs a first level, and controls the power device under test to turn off based on the first level;

[0035] When the detected voltage is less than or equal to the input voltage of the external voltage source, the voltage comparator in the current detection circuit of the power device outputs a second level, and controls the power device under test to turn on based on the second level.

[0036] In addition, to achieve the above objectives, the present invention also provides an automotive compressor, the automotive compressor including a controller, a power device to be detected, a motor and a compression section, wherein the controller is provided with a current detection circuit for the power device;

[0037] The controller is connected to the power device under test, the power device under test is connected to the motor, and the motor is connected to the compression unit;

[0038] The controller is used to perform the steps of the current detection method for the power device described above.

[0039] Furthermore, to achieve the above objectives, the present invention also provides a vehicle including an automotive compressor, the automotive compressor being used to perform the steps of the above-described power device current detection method.

[0040] This invention provides a current detection circuit for a power device. The circuit includes a current power device unit, the input terminal of which is connected to the power device under test and a power supply, wherein the current power device unit and the power device under test are driven synchronously; a current sampling unit, the input terminal of which is connected to the output terminal of the current power device unit, the current sampling unit being used to collect the detection voltage of the current power device unit under the synchronous driving state; and a detection chip, the detection chip being connected to the output terminal of the current sampling unit, the detection chip being used to perform current detection on the power device under test based on the detection voltage and a preset overcurrent ratio.

[0041] By connecting the current power device unit to the power device under test and driving it synchronously, the detection voltage of the current power device unit is collected based on the current sampling unit. Finally, the current of the power device under test is detected in the detection chip based on the detection voltage and a preset overcurrent ratio. This avoids the phenomenon of abnormal breakdown of the high-power sampling resistor that occurs when the detection current of a high-current power device increases, as seen in existing technologies. This current detection circuit for power devices can realize the current detection of the high-current power device (the power device under test) based on the current detection trigger of the current power device unit, thus realizing a new current detection method for power devices. On the other hand, because a current power device unit is used, there is no need to use a high-power sampling resistor in the current sampling unit, thereby reducing the cost of current detection. At the same time, the current sampling unit is not in the main current loop of the power device under test, so there is no phenomenon of abnormal breakdown of the resistor in the current sampling unit caused by the increased current of the high-current power device, thus improving the current detection accuracy of the power device. Attached Figure Description

[0042] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on the structures shown in these drawings without creative effort.

[0043] Figure 1 This is a schematic diagram of a module of the current detection circuit for the power device in this application;

[0044] Figure 2 This is a schematic diagram of the current detection circuit for an existing power device.

[0045] Figure 3 This is a schematic diagram of the current detection circuit for the power device in this application.

[0046] Figure 4 This is another connection diagram of the current detection circuit for the power device in this application;

[0047] Figure 5 This is a schematic diagram of the structure of an automotive compressor in the hardware operating environment involved in an embodiment of the present invention;

[0048] Figure 6 This is a schematic flowchart of the current detection method for the power device of the present invention;

[0049] Figure 7 This is a schematic diagram of the automotive compressor module of the present invention.

[0050] The realization of the purpose, functional features and advantages of this application will be further explained in conjunction with the embodiments and with reference to the accompanying drawings.

[0051] Explanation of icon numbers:

[0052] 100. Current detection circuit for power devices; 10. Current power device unit; 20. Current sampling unit; 30. Detection chip; 200 (Q1), power device under test; 300 (VCC), power supply; RX, sampling resistor; R1, first resistor; R2, second resistor; R3, third resistor; R4, fourth resistor; C1, first capacitor; U, operational amplifier; Q2, sampling power device; 400. External driver; 21. Operational amplifier subunit; X, voltage comparator; Vth, external voltage source; 0001. Communication bus; 0002. Acquisition interface; 0003. Processor; 0004. Processing interface; 0005. Memory. Detailed Implementation

[0053] It should be understood that the specific embodiments described herein are merely illustrative of this application and are not intended to limit this application.

[0054] To better understand the technical solution of this application, a detailed description will be provided below in conjunction with the accompanying drawings and specific implementation methods.

[0055] In applications such as inverter circuits where high-current power devices exist, a common method for sampling the current of these devices is to connect a sampling resistor in series with the device. The voltage drop across the sampling resistor is then measured to calculate the current. (See reference...) Figure 2 , Figure 2 This diagram illustrates the connection of a current detection circuit for existing power devices. Q1 represents a high-current power device. In this case, the sampling resistor is directly connected to the high-current power device to obtain its current. However, this method requires a resistor or current sensor with high power and high temperature resistance, resulting in high cost (due to the large package size and high power of the resistor, space constraints, device heat generation considerations, and higher cost, all of which pose challenges for designers). Furthermore, since the resistor or current sensor is placed in the main current path, it cannot withstand the current exceeding a certain value, thus limiting its ability to handle large currents. Another approach is to connect multiple sampling resistors in series, using voltage division to collect smaller voltages and determine the corresponding current. However, this method increases sampling costs and introduces more uncertainties (such as errors in the sampling resistor value), leading to lower accuracy in current detection for power devices.

[0056] Therefore, based on the shortcomings of the above-mentioned current detection methods for power devices, this application proposes a current detection circuit for power devices. The main solution of this application embodiment is: by connecting a current power device unit to the power device under test and driving synchronously, the detection voltage of the current power device unit is collected based on the current sampling unit. Finally, the current of the power device under test is detected in the detection chip based on the detection voltage and a preset overcurrent ratio. This avoids the phenomenon of abnormal breakdown of the high-power sampling resistor that occurs as the detection current of a high-current power device increases, as is the case in the prior art. This current detection circuit for power devices can realize the current detection of the high-current power device (the power device under test) based on the current detection trigger of the current power device unit, thus realizing a new current detection method for power devices. On the other hand, since a current power device unit is used, there is no need to use a high-power sampling resistor in the current sampling unit, thereby reducing the cost of current detection. At the same time, the current sampling unit is not in the main current loop of the power device under test, so there is no phenomenon of abnormal breakdown of the resistor in the current sampling unit caused by the increase of the detection current of the high-current power device, thereby improving the current detection accuracy of the power device.

[0057] Based on this, embodiments of this application provide a control device for a parallel power module, referring to... Figure 1 , Figure 1 This is a schematic diagram of one module of the current detection circuit for the power device in this application.

[0058] Reference Figure 1 This application provides a current detection circuit 100 for a power device, comprising:

[0059] The input terminal of the current power device unit 10 is connected to the power device under test 200 and the power supply 300, wherein the current power device unit 10 and the power device under test 200 are driven synchronously.

[0060] The current sampling unit 20 has its input terminal connected to the output terminal of the current power device unit 10. The current sampling unit 20 is used to collect the detection voltage of the current power device unit 10 under synchronous drive conditions.

[0061] The detection chip 30 is connected to the output terminal of the current sampling unit 20. The detection chip 30 is used to detect the current of the power device 200 under test based on the detection voltage and the preset overcurrent ratio.

[0062] In this embodiment, a new current power device unit 10 is added to the current detection circuit 100 of the power device. This allows the current sampling unit 20 to collect the detection voltage of the current power device unit 10 while the current power device unit 10 and the power device under test 200 are driven synchronously. The detection voltage is then transmitted back to the detection chip 30, which can then detect the voltage and a preset overcurrent ratio to perform current detection on the power device under test 200, thus completing the detection of the high-current power device 200. Synchronous driving refers to simultaneously controlling the power device in the current power device unit 10 and the power device under test 200 to turn on or off simultaneously, ensuring accurate subsequent detection and preventing high current from being directly applied to the power device in the current power device unit 10, which could damage the power device in the current power device unit 10 and the sampling resistor in the current sampling unit 20. It is worth noting that the synchronous drive state can use the same driver to drive, and ensure that the drive signal arrives at the two power devices at the same time, that is, ensure that the loss and delay of the transmission line are the same. The detection voltage refers to the detection voltage of the power device in the current detection power device unit 10. The preset overcurrent ratio refers to the ratio of the current passing through the power device in the current power device unit 10 to the power device 200 under test. For example, if the ratio is 1:100, and the current value corresponding to the detection voltage is A, then the current value of the power device 200 under test can be determined to be 100A, thereby enabling efficient and accurate current detection of the power device 200 under test.

[0063] In one embodiment, the use of the current power device unit 10 can also reduce the risk of damage to the resistor in the current sampling unit 20. This is mainly because the current sampling unit 20 is not on the main current path (the circuit of the power device 200 under test). The large current of the power device 200 under test will not enter the current sampling unit 20, thus preventing abnormal breakdown of the resistor in the current sampling unit 20. That is, the resistor in the current sampling unit 20 does not need to be a high-power resistor; a low-power resistor can be used instead, thereby reducing the cost of current detection of the power device. It is worth noting that the power device in this embodiment can be a MOS (Metal-Oxide-Semiconductor) transistor or an IGBT (Insulated Gate Bipolar Transistor). The specific type of power device is not limited here. It is only necessary to ensure that the overcurrent ratio between the power device in the current power device unit 10 and the power device 200 under test is adaptively selected according to the actual situation and stored in the detection chip 30 for subsequent calculations.

[0064] In this embodiment, a current detection circuit for a power device is provided. The circuit includes a current power device unit, the input of which is connected to the power device under test and a power supply, wherein the current power device unit and the power device under test are driven synchronously; a current sampling unit, the input of which is connected to the output of which is used to collect the detection voltage of the current power device unit under the synchronous driving state; and a detection chip, connected to the output of the current sampling unit, used to perform current detection on the power device under test based on the detection voltage and a preset overcurrent ratio. By connecting the current power device unit to the power device under test and driving synchronously, and then collecting the detection voltage of the current power device unit based on the current sampling unit, the current of the power device under test is finally detected in the detection chip based on the detection voltage and a preset overcurrent ratio. This avoids the phenomenon in existing technologies where the detection current of high-current power devices increases, leading to abnormal breakdown of the high-power sampling resistor. This current detection circuit for power devices can achieve current detection of high-current power devices (the sampling power device under test) based on the current detection trigger of the current power device unit, thus realizing a new current detection method for power devices. On the other hand, because it uses a current power device unit, there is no need to use a high-power sampling resistor in the current sampling unit, thereby reducing the cost of current detection. At the same time, the current sampling unit is not in the main current loop of the sampling power device under test, so there is no phenomenon of abnormal breakdown of the resistor in the current sampling unit caused by the increased detection current of the high-current power device, thereby improving the current detection accuracy of power devices.

[0065] Furthermore, based on the first embodiment of the current detection circuit of the power device, a second embodiment of this application is proposed, referring to... Figure 3 , Figure 3 This is a schematic diagram of the current detection circuit of the power device of this application. The current power device unit 10 includes:

[0066] The sampling power device Q2 has its drain connected to the drain of the power device Q1 under test and the power supply 300. The gate of the sampling power device Q2 is connected to the gate of the power device Q1 under test and the output terminal of the external driver 400. The source of the sampling power device Q2 is connected to the current sampling unit 20.

[0067] In this embodiment, the current power device unit 10 can be directly composed of a sampling power device Q2. The overcurrent between the sampling power device Q2 and the power device Q1 under test is proportional. The sampling power device Q2 is a power device that carries a smaller current between the two. Because the sampling power device Q2 is connected to the current sampling unit 20, the voltage of the sampling power device Q2 can be acquired. The corresponding current is then determined based on the acquired voltage. Based on the existing proportional relationship between the overcurrent of the sampling power device Q2 and the power device Q1 under test, the current value of the power device Q1 under test is determined, thus avoiding the drawback of directly connecting the current sampling unit 20 to the power device Q1 under test. It is worth noting that the proportional relationship between the overcurrent of the sampling power device Q2 and the power device Q1 under test can be determined according to the actual selection of the sampling power device Q2 and the power device Q1 under test, and the proportional relationship is not limited here.

[0068] Furthermore, based on the first and / or second embodiments of the current detection circuit using power devices, a third embodiment of this application is proposed, wherein the current sampling unit 20 includes:

[0069] The sampling resistor RX has its first end connected to the sampling power device Q2 in the current power device unit 10, and its second end grounded.

[0070] Operational amplifier subunit 21, the input terminal of operational amplifier subunit 21 is connected to the first terminal and the second terminal of sampling resistor RX, and the output terminal of operational amplifier subunit 21 is connected to detection chip 30;

[0071] The first resistor R1, the first end of which is connected to the output terminal of the operational amplifier subunit 21;

[0072] The first capacitor C1 has its first terminal connected to the second terminal of the first resistor R1, and its second terminal is grounded.

[0073] Furthermore, the operational amplifier subunit 21 includes:

[0074] The second resistor R2, the first end of which is connected to the first end of the sampling resistor RX;

[0075] The third resistor R3, the first end of which is connected to the second end of the sampling resistor RX;

[0076] Operational amplifier U, the first input terminal of operational amplifier U is connected to the second terminal of the second resistor R2, the second input terminal of operational amplifier U is connected to the second terminal of the third resistor R3, and the output terminal of operational amplifier U is connected to the first terminal of the first resistor R1 and the detection chip 30.

[0077] The fourth resistor R4 is connected to the first input terminal of the operational amplifier U and to the output terminal of the operational amplifier U.

[0078] In this embodiment, the current sampling unit 20 can be composed of a sampling resistor RX, an operational amplifier subunit 21, and related instruments. Since it is directly used to acquire the current flowing through the small-current sampling power device Q2, a high-power resistor RX is unnecessary, reducing the overall cost of the current sampling unit 20. Furthermore, because the sampling resistor RX is not connected to the main circuit of the power device Q1 under test, there is no abnormal breakdown of the main circuit current on the power device Q1, thus ensuring the safety and accuracy of the current detection. The operational amplifier U can be a commonly used voltage acquisition amplifier, which can output based on the voltage across the sampling resistor RX. It is worth noting that if the current flowing through the sampling power device Q2 is very small, a small-current acquisition device can be used directly, such as the current acquisition function integrated within the chip, without the need for the sampling resistor RX and its related circuitry, thereby significantly reducing the current detection cost of the power device Q1 under test.

[0079] In one embodiment, reference is made to Figure 3 The power device under test, Q1, is a high-current main MOSFET, and the sampling power device, Q2, is a low-current secondary MOSFET. The two MOSFETs are connected in parallel, and the control signal G is simultaneously connected to the control terminals of both MOSFETs to achieve control synchronization. The sampling resistor RX is connected in series with the sampling power device Q2, and its conduction current is the same as that of the sampling power device Q2. The two ends of the sampling resistor RX are differentially connected to the operational amplifier subunit 21. The output signal of the operational amplifier subunit 21 is sent to the detection chip 30. If the detection chip 30 can be an MCU (Microcontroller Unit), the MCU calculates the current of the power device under test, Q1, based on the ratio between the current of the power device under test, Q1, and the sampling power device, Q2. It is worth noting that to ensure control synchronization, a synchronous switch can be set between the sampling power device Q2 and the power supply 300. The drive signal of this synchronous switch is the same as the turn-on signal of the power device under test, Q2. Therefore, the synchronous switch can only be closed when the power device under test, Q2, is turned on, allowing the sampling power device Q2 to begin current detection.

[0080] Furthermore, based on the first, second, and / or third embodiments of the current detection circuit using power devices, a fourth embodiment of this application is proposed, with reference to... Figure 4 , Figure 4 This is another connection diagram of the current detection circuit of the power device in this application. The current detection circuit 100 of the power device further includes:

[0081] Voltage comparator X has its first input terminal connected to the output terminal of operational amplifier U in current sampling unit 20, its second input terminal connected to external voltage source Vth, and its output terminal connected to the enable terminal of external driver 400.

[0082] In one embodiment, the detection chip 40 includes:

[0083] The current calculation subunit is connected to the output of the operational amplifier U in the current sampling unit 20. The current calculation subunit is used to perform current detection on the power device Q1 under test based on the detection voltage and the preset overcurrent ratio.

[0084] The current protection subunit is connected to the input terminal of the current calculation subunit and the enable terminal of the external driver 400. The current protection subunit is used to provide current protection for the power device Q1 under test based on the detected voltage.

[0085] In this embodiment, the current detection circuit 100 of the power device also includes a protection function for the power device under test 200 and the sampling power device Q2. The collected voltage is output to a voltage comparator X for comparison with an external voltage source Vth. If the voltage is greater than the external voltage source Vth, the power device under test 200 and the sampling power device Q2 are controlled to turn off. For example, the voltage comparator X outputs a level that controls the external driver 400 to output a signal to turn off the power device under test 200 and the sampling power device Q2. If the voltage is not greater than the external voltage source Vth, the power device under test 200 and the sampling power device Q2 are controlled to remain on or continue to be on. For example, the voltage comparator X outputs a level that controls the external driver 400 to output a signal to turn on or continuously turn on the power device under test 200 and the sampling power device Q2, thereby protecting the power device under test 200 and the sampling power device Q2. The voltage comparator X can be any commonly used comparator and is not limited here. Figure 4As shown, the output signal of operational amplifier U is connected to one input of voltage comparator X, and the other input is connected to a set voltage value (the overcurrent protection voltage set value can be proportional to the actual maximum voltage value, and this proportionality is related to the overcurrent between the sampling power device Q2 and the power device Q1 under test). The output of voltage comparator X is connected to the enable terminal of external driver 400 to control the on / off state of the power device under test 200 and the sampling power device Q2. When the circuit current is too large, the voltage drop across the sampling resistor RX will increase, the output voltage of operational amplifier U will increase, and the voltage output of voltage comparator X will flip, thereby shutting down the operation of external driver 400 and realizing the overcurrent protection function for the power device under test 200 and the sampling power device Q2.

[0086] In one embodiment, the detection chip 40 may include a current calculation subunit and a current protection subunit. The current calculation subunit calculates the current value of the power device 200 to be detected, and after obtaining the current value of the power device 200 to be detected, the current protection subunit judges the current value of the power device 200 to realize the current protection function of the voltage comparator X. The current calculation subunit and the current protection subunit may be functional modules set in the detection chip 40. The functional modules may implement the calculation and protection functions based on programs or hardware. The specific composition and programs are not limited here.

[0087] In yet another embodiment, reference is made to... Figure 5 , Figure 5 This is a schematic diagram of the structure of an automotive compressor in the hardware operating environment involved in the embodiments of the present invention.

[0088] like Figure 5 As shown, the automotive compressor may include: a processor 0003, such as a central processing unit (CPU), a communication bus 0001, an acquisition interface 0002, a processing interface 0004, and a memory 0005. The communication bus 0001 is used to enable communication between these components. The acquisition interface 0002 may include an information acquisition device or acquisition unit, such as a computer; optionally, the acquisition interface 0002 may also include a standard wired interface or a wireless interface. The processing interface 0004 may optionally include a standard wired interface or a wireless interface. The memory 0005 may be high-speed random access memory (RAM) or stable non-volatile memory (NVM), such as a disk storage device. Optionally, the memory 0005 may also be a storage device independent of the aforementioned processor 0003.

[0089] Those skilled in the art will understand that Figure 5The structure shown does not constitute a limitation on automotive compressors and may include more or fewer components than illustrated, or combine certain components, or have different component arrangements.

[0090] like Figure 5 As shown, the memory 0005, which is a computer storage medium, may include an operating system, an acquisition interface module, and a processing interface module to execute a current detection program for power devices in an automobile compressor and vehicle.

[0091] exist Figure 5 In the illustrated automotive compressor, the communication bus 0001 is mainly used to realize the connection and communication between components; the acquisition interface 0002 is mainly used to connect to the backend server and communicate data with the backend server; the processing interface 0004 is mainly used to connect to the deployment end (user end) and communicate data with the deployment end; the processor 0003 and the memory 0005 in the automotive compressor of the present invention can be set in the automotive compressor. The automotive compressor calls the current detection program of the power device executed by the automotive compressor stored in the memory 0005 through the processor 0003, and executes the current detection circuit of the power device provided in the embodiment of the present invention.

[0092] Based on the above hardware structure and the first, second, third and / or fourth embodiments of the current detection circuit of the power device, a first embodiment of the current detection method of the power device of the present invention is proposed.

[0093] In one embodiment of the present invention, such as Figure 6 As shown, Figure 6 This is a schematic flowchart of the current detection method for the power device of the present invention. The current detection method for the power device is applied to the current detection circuit of the power device described above, and the current detection method for the power device includes:

[0094] Step S10: Under the state of synchronous driving of the current power device unit and the power device under test, the detection voltage of the current power device unit is acquired by the current sampling unit.

[0095] In this embodiment, when current detection is performed on the power device under test, the current power device unit and the power device under test are first controlled to be in a synchronous driving state based on the external driver, and then the current detection is performed. The synchronous driving state means that the current power device unit and the power device under test are turned on at least simultaneously. This is because the problem of power device damage caused by turning on the power device in the current power device unit alone can be avoided. The synchronous driving design can be the same as the commonly used synchronous driving design, and is not limited here. Furthermore, under synchronous driving conditions (when the power devices in the driving current power device unit and the power device under test are turned on), the current sampling unit acquires the detection voltage of the current power device unit, that is, it acquires the voltage value of the power device (i.e., the sampling power device) in the current power device unit. The detection voltage refers to the detection voltage of the power device in the current power device unit. Finally, the voltage of the power device under test can be determined by the detection voltage of the power device in the current power device unit. Therefore, there is no need to use a high-power sampling resistor in the current sampling unit, which reduces the cost of current detection. At the same time, the current sampling unit is not in the main current loop of the sampling power device under test, so there will be no phenomenon of increased detection current of high-current power device causing abnormal current breakdown of the resistor in the current sampling unit, thereby improving the current detection accuracy of the power device.

[0096] Step S20: Perform current detection on the power device under test according to the detection voltage and the preset overcurrent ratio.

[0097] In this embodiment, after determining the detection voltage, the current of the power device under test is detected based on the detection voltage and the preset overcurrent ratio. The preset overcurrent ratio refers to the ratio of the current passing through the power device in the current power device unit to that of the power device under test. Thus, the smaller current can be collected based on the two current ratio values, and the larger current can be determined to avoid the defects caused by directly collecting the larger current, thereby ensuring the accuracy of the current detection of the power device under test.

[0098] This embodiment provides a current detection method for power devices, applied to a current detection circuit of a power device. The method involves acquiring the detection voltage of the current power device unit (current power device unit) using a current sampling unit while the current power device unit and the power device under test are synchronously driven; and then performing current detection on the power device under test based on the detection voltage and a preset overcurrent ratio. By acquiring the detection voltage of the current power device unit (current power device unit) using a current sampling unit while the current power device unit and the power device under test are synchronously driven, and finally performing current detection on the power device under test based on the detection voltage and a preset overcurrent ratio. This avoids the phenomenon in existing technologies where the detection current of high-current power devices increases, leading to abnormal breakdown of the high-power sampling resistor. This current detection circuit for power devices can achieve current detection of high-current power devices (the sampling power device under test) based on the current detection trigger of the current power device unit, thus realizing a new current detection method for power devices. On the other hand, because it uses a current power device unit, there is no need to use a high-power sampling resistor in the current sampling unit, thereby reducing the cost of current detection. At the same time, the current sampling unit is not in the main current loop of the sampling power device under test, so there is no phenomenon of abnormal breakdown of the resistor in the current sampling unit caused by the increased detection current of the high-current power device, thereby improving the current detection accuracy of power devices.

[0099] In one embodiment, a second embodiment of the current detection method based on a power device is proposed, comprising the step of detecting the current of the power device under test according to the detection voltage and a preset overcurrent ratio, including:

[0100] Step S21: Determine the actual voltage value corresponding to the detection voltage based on the preset overcurrent ratio, and determine the current value corresponding to the actual voltage value.

[0101] Step S22: Use the current value as the current of the power device under test.

[0102] In this embodiment, when determining the current value of the power device under test, the actual voltage value corresponding to the detection voltage is determined based on a preset overcurrent ratio. For example, if the preset overcurrent ratio is 1:100, and the detection voltage is B, and the current value corresponding to the detection voltage B is B1, then the current value of the power device under test 200 can be determined to be 100B1, thus completing the determination of the current of the power device under test. It is worth noting that for each acquired detection voltage, there is a unique corresponding current value. For example, there is a current-voltage correspondence table. The current of the power device under test is determined based on the unique current value corresponding to the detection voltage at this time, thereby eliminating the need to use a high-power resistor for current detection and reducing the current detection cost of the power device under test.

[0103] In one embodiment, after the step of performing current detection on the power device to be detected based on the detection voltage and a preset overcurrent ratio, the process includes:

[0104] Step S30: When the detected voltage is greater than the input voltage of the external voltage source, the voltage comparator in the current detection circuit of the power device outputs a first level and controls the power device under test to turn off based on the first level.

[0105] In step S40, when the detected voltage is less than or equal to the input voltage of the external voltage source, the voltage comparator in the current detection circuit of the power device outputs a second level, and controls the power device under test to turn on based on the second level.

[0106] In this embodiment, after determining the current of the power device under test, protection is also provided for the power device under test. When it is determined that the detection voltage is greater than the input voltage of the external voltage source, or when it is determined that the current value corresponding to the detection voltage is greater than the set first current value, or when it is determined that the current of the power device under test is greater than the set second current value, it is determined that there is an overcurrent risk. Then, the voltage comparator in the current detection circuit of the power device outputs a first level and controls the power device under test to turn off based on the first level. That is, the output terminal of the voltage comparator in the current detection circuit of the power device can be directly connected to the external driver that controls the power device under test and the sampling power device. After receiving the first level, the external driver will control the power device under test and the sampling power device to turn off based on the trigger of the first level, thereby protecting the power device under test and the sampling power device from damage. Here, the input voltage refers to the output voltage of the external voltage source, the first current value refers to the user-defined overcurrent value of the sampling power device, the second current value refers to the user-defined overcurrent value of the power device under test, and the first level refers to the user-defined level that controls the external driver to drive the power device to turn off. Conversely, if the above conditions are not met, such as when the detected voltage is less than or equal to the input voltage of the external voltage source, the voltage comparator in the current detection circuit of the power device outputs a second level, and controls the power device under test to turn on based on the second level. The second level refers to the level defined by the user to control the external driver to drive the power device to turn on. Thus, the safety of the power device under test and the sampling power device can be ensured based on the judgment of current and voltage, while ensuring the accuracy and safety of the entire current detection of the power device under test and the sampling power device.

[0107] Corresponding to the above embodiments, the present invention also proposes an automotive compressor.

[0108] The automotive compressor of this invention includes a controller, a power device to be detected, a motor, and a compression unit, wherein the controller is provided with a current detection circuit for the power device;

[0109] The controller is connected to the power device under test, the power device under test is connected to the motor, and the motor is connected to the compression unit;

[0110] The controller is used to perform the steps of the current detection method for the power device described above.

[0111] According to an embodiment of the present invention, an automotive compressor (which may also be an inverter including power devices) implements the aforementioned power device current detection method when the controller in the automotive compressor executes a program. Based on the aforementioned power device current detection method, in a state where the current power device unit and the power device under test are driven synchronously, the current sampling unit acquires the detection voltage of the current power device unit; the current of the power device under test is detected according to the detection voltage and a preset overcurrent ratio. Since a current power device unit is used, a high-power sampling resistor is not required in the current sampling unit, thereby reducing the cost of current detection. At the same time, since the current sampling unit is not in the main current circuit of the power device under test, there will be no phenomenon of increased detection current of the high-current power device causing abnormal current breakdown of the resistor in the current sampling unit, thereby improving the accuracy of current detection of the power device.

[0112] The controller internally incorporates a current detection circuit for the power device, connected to the power device under test. This allows it to determine the current value of the power device, enabling control of the device and the entire inverter based on this current value. It's worth noting that the automotive compressor may also include other hardware, such as a housing and circuit board, to separately arrange the current detection circuit's current-sensing unit, current sampling unit, and detection chip on the circuit board. The circuit board and its circuitry are then encapsulated within the housing to form the automotive compressor. The controller controls the current detection circuit of the power device to perform current detection on the power device under test.

[0113] Corresponding to the above embodiments, the present invention also proposes a motor control system.

[0114] The motor control system of this invention includes an inverter and a motor, wherein the inverter is connected to the motor.

[0115] The inverter is used to perform the steps of the current detection method for the power device described above.

[0116] The motor control system enables motor control and includes an inverter and a motor. The inverter is connected to the motor to drive its operation. Simultaneously, the inverter performs the current detection method for the power devices described above, accurately and cost-effectively determining the real-time current of the power devices. This allows for motor control based on the real-time current, ensuring accurate motor control and reducing overall motor control costs.

[0117] Corresponding to the above embodiments, the present invention also proposes a vehicle.

[0118] The vehicle in this embodiment of the invention includes an automotive compressor (inverter), which is used to perform the steps of the current detection method for the power device described above.

[0119] The automotive compressor can be installed on the vehicle to achieve precise and low-cost current detection, thereby reducing the overall vehicle design cost and improving the vehicle's control accuracy. It is worth noting that other hardware can also be included on the vehicle; these will not be detailed here. The entire automotive compressor can be installed on the vehicle or on other products, without limitation.

[0120] The present invention also provides a controller, with reference to Figure 7 , Figure 7 This is a schematic diagram of the controller module of the present invention. The controller includes:

[0121] The information acquisition module A01 is used to acquire the detection voltage of the current power device unit collected by the current sampling unit when the current power device unit and the power device under test are driven synchronously.

[0122] The current detection module A02 is used to detect the current of the power device under test based on the detection voltage and the preset overcurrent ratio.

[0123] The methods executed by the above-mentioned program modules can be referred to in the various embodiments of the current detection method for power devices of the present invention, and will not be repeated here.

[0124] The present invention also provides a storage medium.

[0125] The present invention stores an execution program for current detection of a power device on a storage medium. When the current detection program for the power device is executed by a processor, it implements the steps of the current detection method for the power device as described above.

[0126] The method implemented when the current detection program of the power device running on the processor is executed can be referred to in various embodiments of the current detection method of the power device of the present invention, and will not be repeated here.

[0127] It should be noted that, in this document, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or system that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or system. Unless otherwise specified, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or system that includes that element.

[0128] The sequence numbers of the above embodiments of the present invention are for descriptive purposes only and do not represent the superiority or inferiority of the embodiments.

[0129] The above description is merely an optional embodiment of the present invention and does not limit the patent scope of the present invention. All equivalent structural transformations made using the contents of the present invention's specification and drawings under the inventive concept of the present invention, or direct / indirect applications in other related technical fields, are included within the patent protection scope of the present invention.

Claims

1. A current detection circuit for a power device, characterized in that, The current detection circuit of the power device includes: A current power device unit, wherein the input terminal of the current power device unit is connected to the power device under test and the power supply, wherein the current power device unit and the power device under test are driven synchronously; A current sampling unit, wherein the input terminal of the current sampling unit is connected to the output terminal of the current power device unit, and the current sampling unit is used to collect the detection voltage of the current power device unit under the synchronous drive state; A detection chip is connected to the output terminal of the current sampling unit. The detection chip is used to detect the current of the power device under test based on the detection voltage and a preset overcurrent ratio.

2. The current detection circuit for the power device as described in claim 1, characterized in that, The current power device unit includes: A sampling power device, wherein the drain of the sampling power device is connected to the drain of the power device under test and the power supply, the gate of the sampling power device is connected to the gate of the power device under test and the output terminal of an external driver, and the source of the sampling power device is connected to the current sampling unit.

3. The current detection circuit for the power device as described in claim 1, characterized in that, The current sampling unit includes: A sampling resistor, wherein the first end of the sampling resistor is connected to the sampling power device in the current power device unit, and the second end of the sampling resistor is grounded; An operational amplifier subunit is provided, wherein the input terminal of the operational amplifier subunit is connected to the first terminal and the second terminal of the sampling resistor, and the output terminal of the operational amplifier subunit is connected to the detection chip. A first resistor, the first end of which is connected to the output terminal of the operational amplifier subunit; A first capacitor, the first terminal of which is connected to the second terminal of the first resistor, and the second terminal of the first capacitor is grounded.

4. The current detection circuit for the power device as described in claim 3, characterized in that, The operational amplifier subunit includes: A second resistor, the first end of which is connected to the first end of the sampling resistor; A third resistor, wherein the first end of the third resistor is connected to the second end of the sampling resistor; An operational amplifier, wherein the first input terminal of the operational amplifier is connected to the second terminal of the second resistor, the second input terminal of the operational amplifier is connected to the second terminal of the third resistor, and the output terminal of the operational amplifier is connected to the first terminal of the first resistor and the detection chip; A fourth resistor, the first end of which is connected to the first input terminal of the operational amplifier, and the first end of which is connected to the output terminal of the operational amplifier.

5. The current detection circuit of the power device as described in any one of claims 1 to 4, characterized in that, The current detection circuit of the power device also includes: A voltage comparator, wherein the first input terminal of the voltage comparator is connected to the output terminal of the operational amplifier in the current sampling unit, the second input terminal of the voltage comparator is connected to an external voltage source, and the output terminal of the voltage comparator is connected to the enable terminal of an external driver.

6. The current detection circuit of the power device as described in any one of claims 1 to 4, characterized in that, The detection chip includes: A current calculation subunit is provided, the input of which is connected to the output of the operational amplifier in the current sampling unit. The current calculation subunit is used to perform current detection on the power device under test based on the detection voltage and a preset overcurrent ratio. A current protection subunit is provided, which is connected to the input terminal of the current calculation subunit and the enable terminal of the external driver. The current protection subunit is used to provide current protection for the power device under test based on the detected voltage.

7. A current detection method for a power device, characterized in that, The current detection method for the power device is applied to the current detection circuit of the power device as described in any one of claims 1 to 6, and the current detection method for the power device includes the following steps: Under the state of synchronous driving of the current power device unit and the power device under test, the current sampling unit acquires the detection voltage of the current power device unit; The current of the power device under test is detected based on the detection voltage and the preset overcurrent ratio.

8. The current detection method for power devices as described in claim 7, characterized in that, The step of detecting the current of the power device under test based on the detection voltage and a preset overcurrent ratio includes: The actual voltage value corresponding to the detection voltage is determined based on a preset overcurrent ratio, and the current value corresponding to the actual voltage value is also determined. The current value is used as the current of the power device under test.

9. The current detection method for power devices as described in claim 7, characterized in that, After the step of performing current detection on the power device under test based on the detection voltage and the preset overcurrent ratio, the following steps are included: When the detected voltage is greater than the input voltage of the external voltage source, the voltage comparator in the current detection circuit of the power device outputs a first level, and controls the power device under test to turn off based on the first level; When the detected voltage is less than or equal to the input voltage of the external voltage source, the voltage comparator in the current detection circuit of the power device outputs a second level, and controls the power device under test to turn on based on the second level.

10. An automotive compressor, characterized in that, The automotive compressor includes a controller, a power device to be tested, a motor, and a compression unit, wherein the controller is provided with a current detection circuit for the power device as described in any one of claims 1 to 6; The controller is connected to the power device under test, the power device under test is connected to the motor, and the motor is connected to the compression unit; The controller is used to perform the steps of the current detection method for the power device as described in any one of claims 7 to 9.

11. A vehicle, characterized in that, The vehicle includes an automotive compressor for performing the steps of the current detection method for the power device as described in any one of claims 7 to 9.

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