Power device junction temperature prediction circuit and method, compressor and vehicle

Abstract

The invention relates to the technical field of junction temperature prediction, and discloses a power device junction temperature prediction circuit and method, a compressor and a vehicle, and the circuit comprises an inverter driving unit which comprises a target power device; the input end of the current sampling unit is connected with the current acquisition end of the target power device, and the current sampling unit is used for acquiring the phase current of the target power device; the input end of the voltage sampling unit is connected with the voltage acquisition end of the target power device, and the voltage sampling unit is used for acquiring the phase voltage of the target power device; and the junction temperature prediction unit is connected with the output end of the current sampling unit and the output end of the voltage sampling unit, and the junction temperature prediction unit is used for performing junction temperature prediction on the target power device based on the phase current and the phase voltage. The junction temperature prediction cost of the power device is reduced.

Description

Technical Field

[0001] This invention relates to the field of junction temperature prediction technology, and more particularly to a junction temperature prediction circuit, method, 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 placed higher demands on the methods for predicting the junction temperature of power devices.

[0003] Traditional methods for predicting junction temperature in power devices involve placing temperature sensors around the device, typically PTC (Positive Temperature Coefficient) or NTC (Negative Temperature Coefficient) resistors, mounted flush against the device casing. Junction temperature prediction is then based on these resistors. This method has a significant drawback: the high cost of mounting the resistors in close contact with the device contributes to the overall high cost of junction temperature prediction.

[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 propose a power device junction temperature prediction circuit, method, compressor, and vehicle, aiming to solve the technical problem of high cost in power device junction temperature prediction.

[0006] To achieve the above objectives, the present invention provides a power device junction temperature prediction circuit, the power device junction temperature prediction circuit comprising:

[0007] An inverter drive unit, wherein the inverter drive unit includes a target power device;

[0008] A current sampling unit, wherein the input terminal of the current sampling unit is connected to the current acquisition terminal of the target power device, and the current sampling unit is used to acquire the phase current of the target power device;

[0009] A voltage sampling unit, the input terminal of which is connected to the voltage acquisition terminal of the target power device, is used to acquire the phase voltage of the target power device;

[0010] A junction temperature prediction unit is provided, which is connected to the output terminals of the current sampling unit and the voltage sampling unit. The junction temperature prediction unit is used to predict the junction temperature of the target power device based on the phase current and the phase voltage.

[0011] In one embodiment, the current sampling unit includes:

[0012] A current sampling sensor is provided, with its input terminal connected to the current acquisition terminal of the target power device and its output terminal connected to the junction temperature prediction unit.

[0013] In one embodiment, the voltage sampling unit includes:

[0014] A diode, wherein the cathode of the diode is connected to the voltage acquisition terminal of the target power device;

[0015] A voltage sampling resistor, wherein the first end of the voltage sampling resistor is connected to the anode of the diode, and the second end of the voltage sampling resistor is connected to the drive chip in the inverter drive unit;

[0016] A grounding capacitor, wherein the first terminal of the grounding capacitor is connected to the second terminal of the voltage sampling resistor, and the second terminal of the grounding capacitor is grounded;

[0017] A resistive voltage divider unit, wherein the first end of the resistive voltage divider unit is connected to the second end of the voltage sampling resistor, and the second end of the resistive voltage divider unit is connected to the junction temperature prediction unit.

[0018] In one embodiment, the resistive voltage divider subunit includes:

[0019] The first voltage divider resistor, the first end of the first voltage divider resistor serves as the first end of the voltage divider subunit;

[0020] The second voltage divider resistor has its first end connected to the second end of the first voltage divider resistor and serving as the second end of the voltage divider subunit. The second end of the second voltage divider resistor is grounded. The resistance between the first resistance value of the first voltage divider resistor and the second resistance value of the second voltage divider resistor is greater than the third resistance value of the voltage sampling resistor by a preset multiple.

[0021] In one embodiment, the resistive voltage divider subunit includes:

[0022] A voltage follower operational amplifier is provided, wherein the first input terminal of the voltage follower operational amplifier serves as the first terminal of the resistor voltage divider subunit, and the second input terminal of the voltage follower operational amplifier is connected to the output terminal of the voltage follower operational amplifier.

[0023] The third voltage divider resistor, the first end of which is connected to the output terminal of the voltage follower operational amplifier;

[0024] The fourth voltage divider resistor has its first end connected to the second end of the third voltage divider resistor and serves as the second end of the voltage divider subunit. The second end of the fourth voltage divider resistor is grounded.

[0025] In one embodiment, the inverter drive unit includes:

[0026] A driver chip, wherein the voltage output terminal of the driver chip is connected to the voltage sampling unit;

[0027] An upper bridge drive circuit, wherein the gate of the upper bridge power device in the upper bridge drive circuit is connected to the signal output terminal of the drive chip;

[0028] The lower bridge drive circuit has its gate connected to the signal output terminal of the drive chip, and its first terminal is connected to the second terminal of the upper bridge drive circuit.

[0029] A bus capacitor, wherein the first terminal of the bus capacitor is connected to the second terminal of the lower bridge drive circuit, and the second terminal of the bus capacitor is connected to the first terminal of the upper bridge drive circuit.

[0030] When the upper bridge power device is used as the target power device, the first terminal of the target power device is connected to the first terminal of the upper bridge drive circuit and serves as the current acquisition terminal of the target power device, and the second terminal of the target power device is connected to the second terminal of the upper bridge drive circuit and serves as the voltage acquisition terminal of the target power device.

[0031] When the lower bridge power device is used as the target power device, the first terminal of the target power device is connected to the second terminal of the lower bridge drive circuit and serves as the current acquisition terminal of the target power device, and the second terminal of the target power device is connected to the first terminal of the lower bridge drive circuit and serves as the voltage acquisition terminal of the target power device.

[0032] Furthermore, to achieve the above objectives, the present invention also provides a method for predicting the junction temperature of a compressor power device. This method is applied to the aforementioned power device junction temperature prediction circuit and includes the following steps:

[0033] The circuit acquisition information of the target power device in the inverter drive unit is obtained, wherein the circuit acquisition information includes the phase current of the target power device acquired by the current sampling unit and the phase voltage of the target power device acquired by the voltage sampling unit;

[0034] The junction temperature of the target power device is predicted based on the phase current and the phase voltage.

[0035] In one embodiment, the step of predicting the junction temperature of the target power device based on the phase current and the phase voltage includes:

[0036] Determine the constant current, third resistance value, and equivalent diode voltage drop in the preset parameter information, and determine the product between the constant current and the third resistance value as the first voltage value;

[0037] The difference between the phase voltage and the first voltage value is determined as the second voltage value, and the difference between the second voltage value and the equivalent diode voltage drop is determined as the third voltage value;

[0038] The quotient between the third voltage value and the phase current is determined as the on-resistance value, and the temperature value corresponding to the on-resistance value is determined in a preset internal resistance temperature correspondence table, and the temperature value is used as the junction temperature of the target power device.

[0039] In addition, to achieve the above objectives, the present invention also provides a compressor, the compressor including a controller, a motor and a compression unit, wherein the controller is provided with a power device junction temperature prediction circuit;

[0040] The controller is connected to the motor, and the motor is connected to the compression unit;

[0041] The controller is used to execute the steps of the power device junction temperature prediction method described above.

[0042] This application also provides a vehicle, the vehicle comprising:

[0043] The compressor is also used to perform the steps of the power device junction temperature prediction method described above.

[0044] This invention provides a power device junction temperature prediction circuit. The circuit includes an inverter drive unit, which includes a target power device; a current sampling unit, the input of which is connected to the current acquisition terminal of the target power device, and the current sampling unit is used to acquire the phase current of the target power device; a voltage sampling unit, the input of which is connected to the voltage acquisition terminal of the target power device, and the voltage sampling unit is used to acquire the phase voltage of the target power device; and a junction temperature prediction unit, which is connected to the output terminals of the current sampling unit and the voltage sampling unit, and the junction temperature prediction unit is used to predict the junction temperature of the target power device based on the phase current and the phase voltage.

[0045] The circuit acquires the phase current of the target power device in the inverter drive unit through a current sampling unit and the phase voltage of the target power device in the inverter drive unit through a voltage sampling unit. Finally, the junction temperature of the target power device can be predicted based on the phase voltage and phase current. This avoids the high bonding cost associated with resistors being tightly attached to the power device in existing technologies. This power device junction temperature prediction circuit, on the one hand, predicts the junction temperature of the target power device based on the phase current acquired by the current sampling unit and the phase voltage acquired by the voltage sampling unit, thus realizing a new method for power device junction temperature prediction. On the other hand, the current sampling unit and voltage sampling unit can be directly connected to the target power device through circuit lines, avoiding the cost of tightly attaching resistors to the power device (such as the cost of bonding processes and temperature sensing thermal design), thereby reducing the cost of power device junction temperature prediction. Attached Figure Description

[0046] 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.

[0047] Figure 1 This is a schematic diagram of one module of the power device junction temperature prediction circuit of this application;

[0048] Figure 2 This is a circuit diagram of a voltage sampling unit in the power device junction temperature prediction circuit of this application;

[0049] Figure 3 This is another circuit diagram of the voltage sampling unit in the power device junction temperature prediction circuit of this application;

[0050] Figure 4 This is a circuit connection diagram of the power device junction temperature prediction circuit of this application;

[0051] Figure 5 This is a waveform diagram of temperature and internal resistance in the junction temperature prediction circuit of the power device in this application.

[0052] Figure 6 This is a waveform diagram of the sampling time in the junction temperature prediction circuit of the power device in this application;

[0053] Figure 7 This is a schematic flowchart of the power device junction temperature prediction method of the present invention;

[0054] Figure 8This is a schematic diagram of the compressor structure of the hardware operating environment involved in the embodiments of the present invention;

[0055] Figure 9 This is a schematic diagram of the compressor module of the present invention.

[0056] 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.

[0057] Explanation of icon numbers:

[0058] 100. Power device junction temperature prediction circuit; 200. Inverter drive unit; 10. Current sampling unit; 20. Voltage sampling unit; 30. Junction temperature prediction unit; IC. Driver chip; C1. Grounding capacitor; 21. Resistor voltage divider unit; R1. Voltage sampling resistor; D1. Diode; U1. Voltage follower operational amplifier;

[0059] R4, third voltage divider resistor; R5, fourth voltage divider resistor; RI, current sampling resistor; U2, current sampling operational amplifier; R2, first voltage divider resistor; R3, second voltage divider resistor; C2, bus capacitor; Q1-Q6, first power device-sixth power device; 210, upper bridge drive circuit; 220, lower bridge drive circuit; 300, motor; RX, bus resistor; CV, voltage acquisition terminal; CI, current acquisition terminal. Detailed Implementation

[0060] It should be understood that the specific embodiments described herein are merely illustrative of this application and are not intended to limit this application.

[0061] 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.

[0062] In inverter circuits, MOSFET temperature protection typically requires placing a temperature sensor around the MOSFET. A PTC or NTC resistor is usually placed close to the power device housing. The MCU (Microcontroller Unit) then collects the resistor temperature for TJ (junction temperature) prediction protection. However, TJ prediction generally relies on accurately knowing the power device's thermal resistance and calculating it precisely using switching and conduction losses, as shown by the formula Tj = Tc + P * Rth, where Tj is the junction temperature of the power device, Tc is the resistor temperature, P is the power loss, and Pth is the resistor's thermal resistance. However, for power devices, Rth and P are difficult to obtain, so the predicted TJ is only a rough estimate (i.e., theoretically defined Rth and P), resulting in low accuracy. Furthermore, when using a resistor as a temperature sensor for prediction, the sensor needs to be precisely and closely attached to the power device housing. This increases cost due to the sensor's mounting process and the need to design the temperature transmission path, such as using insulation material, further increasing the cost of junction temperature prediction.

[0063] Therefore, based on the shortcomings of the above-mentioned power device junction temperature prediction methods, this application proposes a power device junction temperature prediction circuit. The main solution of this application embodiment is: to collect the phase current of the target power device in the inverter drive unit through a current sampling unit, and to collect the phase voltage of the target power device in the inverter drive unit through a voltage sampling unit. Finally, the junction temperature of the target power device can be predicted based on the phase voltage and phase current. This avoids the high bonding cost of resistor bonding to power devices in the prior art due to the need to tightly attach resistors to the power devices. This power device junction temperature prediction circuit can predict the junction temperature of the target power device based on the phase current collected by the current sampling unit and the phase voltage collected by the voltage sampling unit, thus realizing a new power device junction temperature prediction method. On the other hand, the current sampling unit and the voltage sampling unit can be directly connected to the target power device through circuit lines, avoiding the need for users to invest in the cost of tightly attaching resistors to the power devices (such as the cost of bonding process and temperature sensing thermal design), thereby reducing the junction temperature prediction cost of power devices.

[0064] 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 power device junction temperature prediction circuit of this application.

[0065] Reference Figure 1 This application provides a power device junction temperature prediction circuit, including:

[0066] Inverter drive unit 200, wherein the inverter drive unit 200 includes a target power device Q;

[0067] A current sampling unit 10 is provided, the input terminal of which is connected to the current acquisition terminal CI of the target power device Q. The current sampling unit 10 is used to acquire the phase current of the target power device Q.

[0068] A voltage sampling unit 20 is provided, the input terminal of which is connected to the voltage acquisition terminal CV of the target power device Q. The voltage sampling unit 20 is used to acquire the phase voltage of the target power device Q.

[0069] Junction temperature prediction unit 30 is connected to the output terminal of the current sampling unit 10 and the output terminal of the voltage sampling unit 20. The junction temperature prediction unit 30 is used to predict the junction temperature of the target power device Q based on the phase current and the phase voltage.

[0070] In this embodiment, to avoid the increased cost caused by using a temperature sensor attached to the power device for power device junction temperature prediction, this application proposes using a current sampling unit 10 to collect the current value of the current sampling terminal CI of the target power device Q in the inverter drive unit 100 as the phase current of the target power device Q, and a voltage sampling unit 20 to collect the voltage value of the voltage sampling terminal CV of the target power device Q in the inverter drive unit 100 as the phase voltage of the target power device Q. Finally, the phase voltage and phase current are transmitted to the junction temperature prediction unit 30, which can then predict the junction temperature of the target power device Q based on the phase voltage and phase current. That is, predict the temperature value of the target power device Q. The junction temperature prediction unit 30 can be directly a control chip, microcontroller, or other control center. Here, phase current refers to the phase current in the inverter drive unit 200, phase voltage refers to the phase voltage in the inverter drive unit 200, and target power device refers to the power device in the inverter drive unit 200 whose junction temperature is to be predicted. The junction temperature prediction process is to determine the temperature of the power device based on the phase current and phase voltage. It can be determined directly based on the relevant formulas of the power device temperature and phase current and phase voltage, or it can be determined in other ways, which are not limited here. At this time, the junction temperature of the target power device can be predicted by collecting the phase current and phase voltage, without the need to attach a temperature sensor to the target power device, thereby reducing the junction temperature prediction cost of the power device.

[0071] In one embodiment, reference is made to Figure 6 , Figure 6This is a waveform diagram illustrating the sampling time in the junction temperature prediction circuit for the power device in this application. To ensure the accuracy of phase current and phase voltage acquisition, the sampling frequencies for phase current and phase voltage need to be limited. For example, the sampling frequency of the phase current is K2 times the carrier frequency, and the sampling frequency of Vdesat (i.e., the phase voltage) is K1 times the sampling frequency of the phase current. K1 and K2 are both positive integers greater than or equal to 1, and K2 >= K1, to ensure the accuracy of phase current and phase voltage acquisition, i.e., to prevent interference from the power device. (See reference...) Figure 6 All Vdesat sampling points are sampled within the 0 vector range, meaning that the sampling time of Vdesat must be the 0 vector time. All sampling frequencies are integer multiples of the carrier frequency, in order to improve the accuracy of subsequent junction temperature prediction for power devices by ensuring the accuracy of phase current and phase voltage.

[0072] In this embodiment, a power device junction temperature prediction circuit is provided. The circuit includes an inverter drive unit comprising a target power device; a current sampling unit, the input of which is connected to the current acquisition terminal of the target power device, for acquiring the phase current of the target power device; a voltage sampling unit, the input of which is connected to the voltage acquisition terminal of the target power device, for acquiring the phase voltage of the target power device; and a junction temperature prediction unit, connected to the output terminals of the current and voltage sampling units, for predicting the junction temperature of the target power device based on the phase current and phase voltage. By acquiring the phase current of the target power device in the inverter drive unit through the current sampling unit and the phase voltage of the target power device in the inverter drive unit through the voltage sampling unit, the junction temperature of the target power device can ultimately be predicted based on the phase voltage and phase current. This avoids the high bonding cost associated with bonding resistors to power devices, which is a problem in existing technologies. This power device junction temperature prediction circuit can predict the junction temperature of the target power device based on the phase current collected by the current sampling unit and the phase voltage collected by the voltage sampling unit, thus realizing a new method for predicting the junction temperature of power devices. On the other hand, the current sampling unit and the voltage sampling unit can be directly connected to the target power device through circuit lines, avoiding the cost of bonding resistors to power devices (such as the cost of bonding process and temperature sensing thermal design), thereby reducing the cost of predicting the junction temperature of power devices.

[0073] Furthermore, based on the first embodiment of the power device junction temperature prediction circuit, a second embodiment of this application is proposed, wherein the current sampling unit 10 includes:

[0074] A current sampling sensor is provided, with its input terminal connected to the current acquisition terminal CI of the target power device and its output terminal connected to the junction temperature prediction unit 30.

[0075] In this embodiment, a current sampling sensor can be used to collect phase current. The current sampling sensor is connected to the current acquisition terminal CI of the target power device to input the collected phase current value to the junction temperature prediction unit 30. The junction temperature prediction unit 30 then processes the phase current to obtain the predicted temperature without needing to attach a temperature sensor, thereby reducing the cost of power device junction temperature prediction. It is worth noting that the current sampling sensor can be a Hall sensor for current acquisition, or a combination of a current sampling resistor RI and a current sampling operational amplifier U2. In this case, the current sampling resistor RI is connected to the bridge arm circuit in the inverter drive unit 100, and the input terminal of the current sampling operational amplifier U2 is connected to both ends of the current sampling resistor RI. The output terminal of the current sampling operational amplifier U2 can then output the phase current value. The current sampling operational amplifier U2 can be any commonly used operational amplifier device, which is not limited here. Of course, other methods can also be used for phase current acquisition, which are not limited here.

[0076] Furthermore, based on the first and / or second embodiments of the power device junction temperature prediction circuit, a third embodiment of this application is proposed, referring to... Figure 2 , Figure 2 This is a circuit diagram of a voltage sampling unit in the power device junction temperature prediction circuit of this application. The voltage sampling unit 20 includes:

[0077] Diode D1, the cathode of which is connected to the voltage acquisition terminal CV of the target power device;

[0078] A voltage sampling resistor R1 is provided, with its first end connected to the anode of the diode D1 and its second end connected to the driver chip IC in the inverter drive unit 100.

[0079] A grounding capacitor C1, the first end of which is connected to the second end of the voltage sampling resistor R1, and the second end of the grounding capacitor C1 is grounded;

[0080] The voltage divider unit 21 has its first end connected to the second end of the voltage sampling resistor R1, and its second end connected to the junction temperature prediction unit 30.

[0081] In this embodiment, the voltage sampling unit 20 consists of diodes D1, voltage sampling resistor R1, grounding capacitor C1, and a resistor voltage divider subunit 21. The number of diodes D1 can be selected according to actual needs. For example, if higher anti-interference capability is required, multiple diodes D1 are connected in series. The cathode of the first diode D1 is connected to the voltage acquisition terminal CV of the target power device, and the anode of the last diode D1 is connected to the first terminal of the voltage sampling resistor R1. The equivalent voltage drop of the multiple diodes D1 is recorded in the junction temperature prediction unit 30. At this point, the phase voltage of the target power device in the inverter drive unit 100 can be acquired based on the voltage sampling unit 20, as shown in the reference... Figure 2 As shown in the figure, the phase voltage of the target power device, Vdeast, is given by: Vdeast = Iphase * Rdson + R1 * Idesat + Vf_dn. Here, Iphase is the constant current of the driver IC, i.e., the output current of the driver IC; Rdson is the on-resistance of the target power device; R1 is the third resistance of the voltage sampling resistor R1; Idesat is the sampled phase current; and Vf_dn is the sum of the equivalent voltage drops of multiple diodes D1. Based on the phase voltage of the target power device, Rdson = (Vdeast - R1 * Idesat - Vf_dn) / Iphase can be obtained. This allows the calculation of the on-resistance of the target power device, which in turn determines the junction temperature of the target power device, thus achieving temperature prediction. It is worth noting that the voltage sampling unit 20 can also be configured in other ways, which are not limited here.

[0082] Furthermore, the resistive voltage divider subunit 21 includes:

[0083] The first voltage divider resistor R2, the first end of the first voltage divider resistor R2 serves as the first end of the voltage divider subunit 21;

[0084] The second voltage divider resistor R3 has its first end connected to the second end of the first voltage divider resistor R2 and serves as the second end of the voltage divider subunit 21. The second end of the second voltage divider resistor R3 is grounded. The resistance between the first resistance of the first voltage divider resistor R2 and the second resistance of the second voltage divider resistor R3 is greater than the third resistance of the voltage sampling resistor R1, which is a preset multiple.

[0085] In yet another embodiment, reference is made to... Figure 3 , Figure 3 This is another circuit diagram of the voltage sampling unit in the power device junction temperature prediction circuit of this application. The resistive voltage divider subunit 21 includes:

[0086] A voltage follower operational amplifier U1 is provided, with its first input terminal serving as the first terminal of the resistor voltage divider subunit 21, and its second input terminal connected to the output terminal of the voltage follower operational amplifier U1.

[0087] The third voltage divider resistor R4, the first end of which is connected to the output terminal of the voltage follower operational amplifier U1;

[0088] The fourth voltage divider resistor R5 has its first end connected to the second end of the third voltage divider resistor R4 and serves as the second end of the voltage divider subunit 21. The second end of the fourth voltage divider resistor R5 is grounded.

[0089] In this embodiment, based on the composition of the voltage sampling unit 20, the resistor voltage divider subunit 21 is specifically defined. In this case, the resistor voltage divider subunit 21 can perform resistor voltage division sampling, where the sum of the first resistance value of the first voltage divider resistor R2 and the second resistance value of the second voltage divider resistor R3 is greater than the third resistance value of the voltage sampling resistor R1 by a preset multiple, such as Rtotal >= 5 * R1, to ensure the accuracy of the voltage division. Rtotal is the sum of the first resistance value of the first voltage divider resistor R2 and the second resistance value of the second voltage divider resistor R3. The resistor voltage divider subunit 21 can also perform resistor voltage division sampling after using a voltage follower operational amplifier U1. In this case, the third voltage divider resistor R4, the fourth voltage divider resistor R5, and the voltage sampling resistor R1 have no resistance value requirements. This design is because the voltage sampling unit 20, due to the constant current source output characteristics of the driver chip IC, must have high impedance for its voltage sampling current to reduce interference to the original DEST signal. Furthermore, resistance sampling is performed using a voltage follower operational amplifier U1. Since the voltage follower operational amplifier U1 is essentially at infinite input impedance, there are no requirements for the resistances of the third and fourth voltage divider resistors R4 and R5; the signal can be directly conditioned according to the MCU's AD voltage. When sampling Vdesat using a voltage divider with the first resistor R2 and the second resistor R3, the sum of the first resistance value of the first resistor R2 and the second resistance value of the second resistor R3 must be much greater than the third resistance value of the voltage sampling resistor R1. Other settings can be implemented depending on the actual situation, and are not limited here.

[0090] Furthermore, based on the first, second, and / or third embodiments of the power device junction temperature prediction circuit, a fourth embodiment of this application is proposed, with reference to... Figure 4 , Figure 4 This is a circuit connection diagram of the power device junction temperature prediction circuit of this application. The inverter drive unit 200 includes:

[0091] A driver chip IC, wherein the voltage output terminal of the driver chip IC is connected to the voltage sampling unit 20;

[0092] The upper bridge drive circuit 210, wherein the gate of the upper bridge power device in the upper bridge drive circuit 210 is connected to the signal output terminal of the drive chip IC;

[0093] The lower bridge drive circuit 220 has a gate of the lower bridge power device connected to the signal output terminal of the driver chip IC, and a first terminal of the lower bridge drive circuit 220 is connected to the second terminal of the upper bridge drive circuit 220.

[0094] Bus capacitor C2, the first end of which is connected to the second end of the lower bridge drive circuit 220, and the second end of which is connected to the first end of the upper bridge drive circuit 210;

[0095] When the upper bridge power device is used as the target power device Q, the first end of the target power device Q is connected to the first end of the upper bridge drive circuit 210 and serves as the current acquisition terminal CI of the target power device Q, and the second end of the target power device Q is connected to the second end of the upper bridge drive circuit 210 and serves as the voltage acquisition terminal CV of the target power device Q.

[0096] When the lower bridge power device is used as the target power device Q, the first terminal of the target power device Q is connected to the second terminal of the lower bridge drive circuit 220 and serves as the current acquisition terminal CI of the target power device Q. The second terminal of the target power device Q is connected to the first terminal of the lower bridge drive circuit 220 and serves as the voltage acquisition terminal CV of the target power device Q.

[0097] In this embodiment, the inverter drive unit 100 includes a drive chip IC, an upper bridge drive circuit 210, a lower bridge drive circuit 220, and a bus capacitor C2, which can be referred to as follows. Figure 4Both the upper bridge drive circuit 210 and the lower bridge drive circuit 220 consist of three power devices. A driver chip IC is used to connect to the gates of each power device to drive them. The first terminal of the lower bridge drive circuit 220 is connected to the second terminal of the upper bridge drive circuit 220 and serves as the voltage acquisition terminal CV. It also serves as the midpoint of the bridge arm and is connected to one phase of the motor 300. The inverter drive unit 100 can be configured as shown in the figure, but will not be described in detail here. At this point, any voltage acquisition terminal CV and current acquisition terminal VI can be randomly connected for junction temperature prediction of the power devices. However, this must be for the same power device. Alternatively, the power device in the upper bridge drive circuit 210 can be used as the target power device for junction temperature prediction. However, due to the characteristics of the upper bridge drive circuit 210, the circuits for acquiring current and voltage need to be isolated to ensure the accuracy of the acquired phase current and phase voltage.

[0098] In yet another embodiment, reference is made to... Figure 8 , Figure 8 This is a schematic diagram of the compressor structure of the hardware operating environment involved in the embodiment of the present invention.

[0099] like Figure 8 As shown, the 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 establish 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.

[0100] Those skilled in the art will understand that Figure 8 The structure shown does not constitute a limitation on the compressor and may include more or fewer components than shown, or combine certain components, or have different component arrangements.

[0101] like Figure 8 As shown, the memory 0005, which serves as a computer storage medium, may include an operating system, an acquisition interface module, a processing interface module, and a power device junction temperature prediction program executed by the compressor.

[0102] exist Figure 8 In the compressor shown, 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 with the backend server; the processing interface 0004 is mainly used to connect to the deployment end (user end) and communicate with the deployment end; the processor 0003 and the memory 0005 in the compressor of the present invention can be set in the compressor. The compressor calls the power device junction temperature prediction program stored in the memory 0005 through the processor 0003 and executes the power device junction temperature prediction circuit provided in the embodiment of the present invention.

[0103] Based on the above hardware structure, an embodiment of the power device junction temperature prediction method of the present invention is proposed.

[0104] In one embodiment of the present invention, such as Figure 8 As shown, Figure 8 This is a schematic flowchart of the power device junction temperature prediction method of the present invention. The power device junction temperature prediction method is applied to the above-mentioned power device junction temperature prediction circuit, and the power device junction temperature prediction method includes:

[0105] Step S10: Obtain circuit acquisition information of the target power device in the inverter drive unit, wherein the circuit acquisition information includes the phase current of the target power device acquired by the current sampling unit and the phase voltage of the target power device acquired by the voltage sampling unit.

[0106] In this embodiment, when junction temperature prediction of a target power device is required, circuit acquisition information of the target power device in the inverter drive unit is obtained. This circuit acquisition information includes phase current acquired by a current sampling unit and phase voltage acquired by a voltage sampling unit. In other words, the phase current and phase voltage in the inverter drive unit determine the junction temperature of the power device in the inverter drive unit. It is worth noting that the voltage and current acquisition terminals can be located on the ports of the target power device, rather than on the ports of other power devices, to ensure the accuracy of the junction temperature prediction. Furthermore, using only the acquired phase current and phase voltage to determine the junction temperature of the target power device reduces the cost increase or decrease caused by attaching a temperature sensor.

[0107] Step S20: Predict the junction temperature of the target power device based on the phase current and the phase voltage.

[0108] In this embodiment, after obtaining the phase current and phase voltage, the junction temperature of the target power device is predicted based on the phase current and phase voltage. At this time, the phase current and phase voltage can be input into the relevant calculation formula for calculation or the junction temperature corresponding to the phase current and phase voltage can be obtained directly by looking up a table. Compared with the existing method of bonding temperature sensor, the junction temperature prediction cost of power device can be reduced.

[0109] This embodiment provides a method for predicting the junction temperature of power devices, applied to a power device junction temperature prediction circuit. This method acquires circuit information of a target power device in an inverter drive unit. This circuit information includes phase current collected by a current sampling unit and phase voltage collected by a voltage sampling unit. The junction temperature of the target power device is predicted based on the phase current and phase voltage. By acquiring the phase current of the target power device in the inverter drive unit through the current sampling unit and the phase voltage through the voltage sampling unit, the junction temperature of the target power device can ultimately be predicted based on the phase voltage and phase current. This avoids the high bonding cost associated with bonding resistors to power devices, which is a problem in existing technologies. This power device junction temperature prediction circuit can predict the junction temperature of the target power device based on the phase current collected by the current sampling unit and the phase voltage collected by the voltage sampling unit, thus realizing a new method for predicting the junction temperature of power devices. On the other hand, the current sampling unit and the voltage sampling unit can be directly connected to the target power device through circuit lines, avoiding the cost of bonding resistors to power devices (such as the cost of bonding process and temperature sensing thermal design), thereby reducing the cost of predicting the junction temperature of power devices.

[0110] In one embodiment, based on a first embodiment of a power device junction temperature prediction method, a second embodiment of this application is proposed, wherein the step of predicting the junction temperature of the target power device based on the phase current and the phase voltage includes:

[0111] Step S21: Determine the constant current, third resistance value, and equivalent diode voltage drop in the preset parameter information, and determine the product between the constant current and the third resistance value as the first voltage value;

[0112] Step S22: Determine the difference between the phase voltage and the first voltage value as the second voltage value, and determine the difference between the second voltage value and the equivalent diode voltage drop as the third voltage value;

[0113] Step S23: Determine the quotient between the third voltage value and the phase current as the on-resistance value, determine the temperature value corresponding to the on-resistance value in the preset internal resistance temperature correspondence table, and use the temperature value as the junction temperature of the target power device.

[0114] In this embodiment, when predicting the junction temperature, the constant current, the third resistance, and the equivalent diode voltage drop are determined from the preset parameter information. Then, the product of the constant current and the third resistance is used as the first voltage value. The difference between the phase voltage and the first voltage value is then determined as the second voltage value, and the difference between the second voltage value and the equivalent diode voltage drop is determined as the third voltage value. Finally, the quotient between the third voltage value and the phase current is determined as the on-state resistance. Here, the constant current refers to the user-defined constant current value, typically the output constant current source of the driver chip; the third resistance refers to the resistance of the voltage sampling resistor; the equivalent diode voltage drop is the sum of the equivalent voltage drops of all diodes; and the on-state resistance refers to the on-state resistance of the power device. (See reference...) Figure 2 The phase voltage of the target power device, Vdeast, is given by: Vdeast = Iphase * Rdson + R1 * Idesat + Vf_dn. Here, Iphase is the constant current of the driver IC (i.e., the output current of the driver IC), Rdson is the on-resistance of the target power device, R1 is the third resistance of the voltage sampling resistor R1, Idesat is the sampled phase current, and Vf_dn is the sum of the equivalent voltage drops of multiple diodes D1. Based on this, Rdson can be calculated as: Rdson = (Vdeast - R1 * Idesat - Vf_dn) / Iphase. Finally, the corresponding temperature value can be determined from a preset internal resistance temperature table as the junction temperature of the target power device. (Refer to the table for details.) Figure 5 , Figure 5 This is a waveform diagram of temperature and internal resistance in the junction temperature prediction circuit of the power device in this application. At this time, Tj can be calculated in reverse by looking up the Rdson and Tj curves, so as to realize the junction temperature prediction of the target power device. Based on the predicted junction temperature, the power device or even the entire compressor can be controlled to ensure the accuracy of the operation of the power device or even the entire compressor.

[0115] Corresponding to the above embodiments, the present invention also proposes a compressor.

[0116] The compressor of this embodiment includes a controller, a motor, and a compression unit, wherein the controller is provided with a power device junction temperature prediction circuit;

[0117] The controller is connected to the motor, and the motor is connected to the compression unit;

[0118] The controller is used to execute the steps of the power device junction temperature prediction circuit described above.

[0119] According to an embodiment of the compressor of the present invention, when the controller in the compressor executes a program, the above-mentioned power device junction temperature prediction method is implemented. Based on the above-mentioned power device junction temperature prediction method, circuit acquisition information of the target power device in the inverter drive unit is obtained. The circuit acquisition information includes the phase current of the target power device acquired by the current sampling unit and the phase voltage of the target power device acquired by the voltage sampling unit. The junction temperature of the target power device is predicted based on the phase current acquired by the current sampling unit and the phase voltage acquired by the voltage sampling unit. This realizes a new power device junction temperature prediction method. On the other hand, the current sampling unit and the voltage sampling unit can be directly connected to the target power device through circuit lines to avoid the cost of the user having to attach the resistor to the power device (such as the cost of at least bonding process and temperature sensing thermal design), thereby reducing the junction temperature prediction cost of the power device.

[0120] The controller internally incorporates a junction temperature prediction circuit for the power devices, connected to the motor. This circuit determines the junction temperature of the power devices, allowing for motor control based on this temperature. The motor then drives the compressor unit to achieve its compressor function. It's worth noting that the compressor may also include other hardware, such as a housing and circuit board. The junction temperature prediction circuit and the inverter drive unit within it can be separately arranged on the circuit board, with the circuit board, its circuitry, and the motor encapsulated within the housing to form the compressor. The controller controls the junction temperature prediction circuit to detect the junction temperature of the power devices in the inverter drive unit and also drives the inverter drive unit to control the motor connected to it. It's also worth noting that the controller can be integrated with the junction temperature prediction unit in the junction temperature prediction circuit into a single controller, reducing the number of controllers required.

[0121] Corresponding to the above embodiments, the present invention also proposes a motor control system.

[0122] The motor control system of this invention includes a compressor and a motor, wherein the compressor is connected to the motor.

[0123] The compressor is used to perform the steps of the power device junction temperature prediction method described above.

[0124] The motor control system enables motor control and includes a compressor and a motor. The compressor is connected to the motor to drive its operation. Simultaneously, the compressor performs the steps of the aforementioned power device junction temperature prediction method, accurately and cost-effectively determining the real-time temperature of the power device. This allows for motor control based on the real-time temperature, ensuring accurate motor control and reducing overall motor control costs.

[0125] Corresponding to the above embodiments, the present invention also proposes a vehicle.

[0126] The vehicle in this embodiment of the invention includes a compressor, which is used to perform the steps of the power device junction temperature prediction method described above.

[0127] The compressor can be installed on the vehicle to achieve accurate and low-cost junction temperature prediction, thereby reducing the overall vehicle design cost and improving the vehicle's control precision. It is worth noting that other hardware can also be included on the vehicle, which will not be detailed here. The compressor can be installed on the vehicle or on other products; this is not a limitation.

[0128] The present invention also provides a compressor, with reference to Figure 9 , Figure 9 This is a schematic diagram of the compressor module of the present invention, wherein the compressor includes:

[0129] Information acquisition module A01 is used to acquire circuit acquisition information of the target power device in the inverter drive unit, wherein the circuit acquisition information includes the phase current of the target power device acquired by the current sampling unit and the phase voltage of the target power device acquired by the voltage sampling unit.

[0130] Junction temperature prediction module A02 is used to predict the junction temperature of the target power device based on the phase current and the phase voltage.

[0131] Optionally, the junction temperature prediction module A02 is further configured to:

[0132] Determine the constant current, third resistance value, and equivalent diode voltage drop in the preset parameter information, and determine the product between the constant current and the third resistance value as the first voltage value;

[0133] The difference between the phase voltage and the first voltage value is determined as the second voltage value, and the difference between the second voltage value and the equivalent diode voltage drop is determined as the third voltage value;

[0134] The quotient between the third voltage value and the phase current is determined as the on-resistance value, and the temperature value corresponding to the on-resistance value is determined in a preset internal resistance temperature correspondence table, and the temperature value is used as the junction temperature of the target power device.

[0135] The methods executed by the above-mentioned program modules can be referred to in the various embodiments of the optimization method of internal linkage of the present invention, and will not be repeated here.

[0136] The present invention also provides a storage medium.

[0137] The present invention stores a power device junction temperature prediction program executed by a compressor on a storage medium. When the power device junction temperature prediction program is executed by a processor, it implements the steps of the power device junction temperature prediction circuit as described above.

[0138] The method implemented when the power device junction temperature prediction program running on the processor is executed can be referred to in various embodiments of the power device junction temperature prediction method of the present invention, and will not be repeated here.

[0139] 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.

[0140] 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.

[0141] 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 power device junction temperature prediction circuit, characterized by, The power device junction temperature prediction circuit comprises: An inverter drive unit, which comprises a target power device; A current sampling unit, an input end of which is connected to a current collection end of the target power device, and which is configured to collect phase current of the target power device; A voltage sampling unit, an input end of which is connected to a voltage collection end of the target power device, and which is configured to collect phase voltage of the target power device; A junction temperature prediction unit, which is connected to an output end of the current sampling unit and an output end of the voltage sampling unit, and which is configured to predict junction temperature of the target power device based on the phase current and the phase voltage.

2. The power device junction temperature prediction circuit of claim 1, wherein, The current sampling unit comprises: A current sampling sensor, an input end of which is connected to a current collection end of the target power device, and an output end of which is connected to the junction temperature prediction unit.

3. The power device junction temperature prediction circuit of claim 1, wherein, The voltage sampling unit comprises: A diode, a cathode of which is connected to a voltage collection end of the target power device; A voltage sampling resistor, a first end of which is connected to an anode of the diode, and a second end of which is connected to a drive chip in the inverter drive unit; A grounding capacitor, a first end of which is connected to the second end of the voltage sampling resistor, and a second end of which is grounded; A resistance voltage dividing subunit, a first end of which is connected to the second end of the voltage sampling resistor, and a second end of which is connected to the junction temperature prediction unit.

4. The power device junction temperature prediction circuit of claim 3, wherein, The resistance voltage dividing subunit comprises: A first voltage dividing resistor, a first end of which serves as the first end of the resistance voltage dividing subunit; A second voltage dividing resistor, a first end of which is connected to a second end of the first voltage dividing resistor, and a second end of which serves as the second end of the resistance voltage dividing subunit, and a second end of which is grounded, wherein a resistance value sum of a first resistance value of the first voltage dividing resistor and a second resistance value of the second voltage dividing resistor is greater than a third resistance value of the voltage sampling resistor by a preset multiple.

5. The power device junction temperature prediction circuit of claim 3, wherein, The resistance voltage dividing subunit comprises: A voltage follower operational amplifier, a first input end of which serves as the first end of the resistance voltage dividing subunit, and a second input end of which is connected to an output end of the voltage follower operational amplifier; A third voltage dividing resistor, a first end of which is connected to the output end of the voltage follower operational amplifier; A fourth voltage dividing resistor, a first end of which is connected to a second end of the third voltage dividing resistor, and a second end of which serves as the second end of the resistance voltage dividing subunit, and a second end of which is grounded.

6. The power device junction temperature prediction circuit of any one of claims 1 to 5, wherein, The inverter drive unit comprises: A drive chip, a voltage output end of which is connected to the voltage sampling unit; An upper bridge drive circuit, a gate of an upper bridge power device in the upper bridge drive circuit is connected to a signal output end of the drive chip; A lower bridge driving circuit, a gate of a lower bridge power device in the lower bridge driving circuit is connected with a signal output end of the driving chip, a first end of the lower bridge driving circuit is connected with a second end of the upper bridge driving circuit; A bus capacitor, a first end of the bus capacitor is connected with a second end of the lower bridge driving circuit, a second end of the bus capacitor is connected with a first end of the upper bridge driving circuit When the upper bridge power device is the target power device, a first end of the target power device is connected with a first end of the upper bridge driving circuit and serves as a current collection end of the target power device, a second end of the target power device is connected with a second end of the upper bridge driving circuit and serves as a voltage collection end of the target power device; When the lower bridge power device is the target power device, a first end of the target power device is connected with a second end of the lower bridge driving circuit and serves as a current collection end of the target power device, a second end of the target power device is connected with a first end of the lower bridge driving circuit and serves as a voltage collection end of the target power device.

7. A method of power device junction temperature prediction, characterized by, The power device junction temperature prediction method is applied to the power device junction temperature prediction circuit in any one of claims 1 to 6, and the power device junction temperature prediction method comprises the following steps: Obtaining circuit collection information of a target power device in an inverter driving unit, wherein the circuit collection information comprises phase current collected by a current sampling unit and phase voltage collected by a voltage sampling unit; Performing junction temperature prediction on the target power device according to the phase current and the phase voltage.

8. The power device junction temperature prediction method of claim 7, wherein, The step of performing junction temperature prediction on the target power device according to the phase current and the phase voltage comprises: Determining a constant current, a third resistance value and an equivalent diode voltage drop in preset parameter information, and determining a product of the constant current and the third resistance value as a first voltage value; Determining a difference between the phase voltage and the first voltage value as a second voltage value, and determining a difference between the second voltage value and the equivalent diode voltage drop as a third voltage value; Determining a quotient between the third voltage value and the phase current as an on-resistance value, determining a temperature value corresponding to the on-resistance value in a preset on-resistance temperature corresponding table, and taking the temperature value as a junction temperature of the target power device.

9. A compressor characterized by, The compressor comprises a controller, a motor and a compression part, wherein the controller is provided with a power device junction temperature prediction circuit; The controller is connected with the motor, and the motor is connected with the compression part; The controller is used to perform the steps of the power device junction temperature prediction method in any one of claims 7 to 8.

10. A vehicle characterized by comprising: The vehicle comprises a compressor, and the compressor is used to perform the steps of the power device junction temperature prediction method in any one of claims 7 to 8.

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