Sic power module loss determination method, storage medium and computer device

Abstract

The present application relates to the technical field of power module loss determination, and specifically provides an SIC power module loss determination method, a storage medium and a computer device. An SIC power module works in a DPWM mode, and the method comprises: acquiring present phase current information, present bus voltage information and present power factor angle information of the SIC power module; acquiring present modulation ratio information in the DPWM mode; and, on the basis of the present phase current information, the present bus voltage information, the present power factor angle information and the present modulation ratio information, determining the present loss of the SIC power module. The technical solutions provided by the present application can more conveniently and accurately determine in real time the losses of SIC power modules in DPWM modes, thereby greatly reducing system load rates.

Description

SIC power module loss determination method, storage medium and computer equipment

[0001] This application claims priority to Chinese patent application CN202311765786.1, filed on December 20, 2023, entitled “SIC power module loss determination method, storage medium and computer equipment”. The entire contents of the above Chinese patent application are incorporated into this application by reference. Technical Field

[0002] The present application relates to the technical field of power module loss determination, and specifically provides a SIC power module loss determination method, storage medium, and computer equipment. Background Art

[0003] Accurately determining power module losses within an inverter is a crucial prerequisite for estimating junction temperature, input power, bus current, and torque. Different PWM (Pulse Width Modulation) control strategies can be employed depending on the inverter application, controlled object, and control objectives. Common PWM control methods include SPWM (Sine Pulse Width Modulation), SVPWM (Space Vector Pulse Width Modulation), and DPWM (Discontinuous Pulse Width Modulation). Because SPWM's modulation wave only contains the fundamental wave and is symmetrical, its losses are simple and convenient to determine, and its loss model is widely used in the industry. However, due to the limitations of SPWM's modulation method, its DC side voltage utilization is low. Therefore, SVPWM or DPWM are the most widely used in the industry. These two methods can improve DC side voltage utilization by approximately 10% compared to SPWM. Since DPWM modulation reduces the number of switching times by 1 / 3 compared to SVPWM, it can reduce the switching loss by up to half, improve the inverter efficiency and reduce the IGBT junction temperature. In the high modulation ratio area, DPWM has limited increase in the harmonics of the motor current, so it has certain advantages.

[0004] In the prior art, there are two methods for determining the loss of power modules under DPWM modulation: offline and online. Since the offline method cannot determine the loss in real time, it can only be used for post-processing of data. The online method, on the other hand, can calculate the conduction loss and switching loss of each device in real time based on the magnitude of each parameter within an electrical cycle, integrating the losses within an electrical cycle and then averaging them. During this process, as long as a device is conducting or switching, its conduction loss or switching loss is calculated in real time, and then the integrated loss is accumulated. This method requires attention to each conduction and switching action of each device, and requires integral calculations. Therefore, the amount of calculation is very large, which increases the system load rate and places high demands on the system's computing power. It cannot be run in real time in systems with low computing power. Summary of the Invention

[0005] In order to solve the above technical problems, the present application proposes a SIC power module loss determination method, storage medium and computer device, which can more conveniently and accurately determine the loss of the SIC power module in real time under the DPWM modulation mode, thereby greatly reducing the system load rate.

[0006] To achieve the above objectives, the technical solution of this application is implemented as follows:

[0007] In a first aspect, the present application provides a method for determining loss of a SIC power module, wherein the SIC power module operates in a DPWM modulation mode; the method comprising:

[0008] Acquiring current phase current information of the SIC power module, current bus voltage information of the SIC power module, and current power factor angle information of the SIC power module;

[0009] Obtaining current modulation ratio information under the DPWM modulation mode;

[0010] The current loss of the SIC power module is determined based on the current phase current information, the current bus voltage information, the current power factor angle information, and the current modulation ratio information.

[0011] In some embodiments, the SIC power module includes a plurality of chip units for performing circuit on / off control; each chip unit includes: a switching device of the MOSFET type, and a diode connected in parallel with the switching device; and determining the current loss of the SIC power module based on the current phase current information, the current bus voltage information, the current power factor angle information, and the current modulation ratio information includes:

[0012] Determining current losses of all switching devices in the SIC power module based on the current phase current information, the current bus voltage information, the current power factor angle information, and the current modulation ratio information;

[0013] Based on the current losses of all the switching devices, a current loss of the SIC power module is determined.

[0014] In some embodiments, determining the current losses of all switching devices in the SIC power module based on the current phase current information, the current bus voltage information, the current power factor angle information, and the current modulation ratio information includes:

[0015] Determining current conduction losses of all switching devices in the SIC power module based on the current phase current information, the current power factor angle information, and the current modulation ratio information;

[0016] Determining current switching losses of all switching devices in the SIC power module based on the current phase current information, the current bus voltage information, and the current power factor angle information;

[0017] Based on the current conduction losses of all the switching devices and the current switching losses of all the switching devices, current losses of all the switching devices in the SIC power module are determined.

[0018] In some embodiments, the current phase current information includes: a current phase current amplitude; the current power factor angle information includes: a current power factor angle; the current modulation ratio information includes: a current modulation ratio; and determining the current conduction loss of all switching devices in the SIC power module based on the current phase current information, the current power factor angle information, and the current modulation ratio information includes:

[0019] Inputting the current phase current amplitude, the current power factor angle, and the current modulation ratio into a pre-constructed first expression, so that the first expression outputs the current conduction loss of each switching device; wherein the first expression is pre-constructed based on the relationship between the current phase current amplitude, the current power factor angle, the current modulation ratio, the ratio value of the on-resistance of each switching device, the bias value of the on-resistance of each switching device, and the current conduction loss of each switching device, and the ratio value and the bias value are both constants;

[0020] The sum of the current conduction losses of each of the switching devices is calculated to obtain the current conduction losses of all the switching devices in the SIC power module.

[0021] In some embodiments, the current phase current information includes: a current phase current amplitude; the current bus voltage information includes: a current bus voltage magnitude; the current power factor angle information includes: a current power factor angle magnitude; and determining the current switching loss of all switching devices in the SIC power module based on the current phase current information, the current bus voltage information, and the current power factor angle information includes:

[0022] Inputting the current phase current amplitude, the current bus voltage, and the current power factor angle into a pre-constructed second expression, so that the second expression outputs the current switching loss of each switching device; wherein the second expression is pre-constructed based on the relationship between the current phase current amplitude, the current bus voltage, the current power factor angle, the switching frequency of each switching device, the energy consumed when each switching device is turned on once, the energy consumed when each switching device is turned off once, the bus reference voltage value of the SIC power module, the reference current value output by the SIC power module, and the current switching loss of each switching device, and the switching frequency, the energy consumed when each switching device is turned on once, the energy consumed when each switching device is turned off once, the bus reference voltage value, and the reference current value are all constants;

[0023] The sum of the current switching losses of each of the switching devices is calculated to obtain the current switching losses of all the switching devices in the SIC power module.

[0024] In some embodiments, determining the current losses of all switching devices in the SIC power module based on the current conduction losses of all switching devices and the current switching losses of all switching devices includes:

[0025] The sum of the current conduction losses of all the switching devices and the current switching losses of all the switching devices is calculated to obtain the current losses of all the switching devices in the SIC power module.

[0026] In some embodiments, determining the current loss of the SIC power module based on the current losses of all the switching devices includes:

[0027] The current losses of all the switching devices are obtained as the current loss of the SIC power module.

[0028] In some embodiments, the method further comprises:

[0029] Determining current conduction losses of all switching devices in the SIC power module based on the current phase current information, the current power factor angle information, and the current modulation ratio information;

[0030] Based on the current conduction losses of all the switching devices, a current total conduction loss of the SIC power module is determined.

[0031] In some embodiments, the method further comprises:

[0032] Determining current switching losses of all switching devices in the SIC power module based on the current phase current information, the current bus voltage information, and the current power factor angle information;

[0033] Based on the current switching losses of all the switching devices, a current total switching loss of the SIC power module is determined.

[0034] In a second aspect, the present application provides a computer-readable storage medium storing a plurality of program codes, wherein the program codes are suitable for being loaded and run by a processor to execute the SIC power module loss determination method described in any one of the technical solutions in the first aspect.

[0035] In a third aspect, the present application provides a computer device, comprising a storage device and a processor, wherein the storage device stores program code that can be run on the processor, and when the program code is executed by the processor, the SIC power module loss determination method described in any one of the technical solutions in the first aspect is implemented.

[0036] The SIC power module loss determination method, storage medium, and computer device provided in the embodiments of the present application obtain the current phase current information, current bus voltage information, and current power factor angle information of the SIC power module, and obtain the current modulation ratio information in the DPWM modulation mode. Based on the above current phase current information, current bus voltage information, current power factor angle information, and current modulation ratio information, the current loss of the SIC power module is determined. This allows the determination of the current loss of the SIC power module to be based on the current electrical parameters. That is, the present application can obtain the SIC power module loss corresponding to any moment based on the electrical parameters at that moment. Compared with the prior art method that requires integrating and accumulating the loss of an electrical cycle, the present application can obviously determine the current loss of the power module more conveniently and promptly. Moreover, the present application simultaneously determines the power module loss based on the current phase current information, current bus voltage information, current power factor angle information, and current modulation ratio information, comprehensively considering various electrical parameters that affect the power module loss, and thus can obtain accurate determination results. It can be seen that the technical solution provided in the embodiment of the present application can more conveniently and accurately determine the loss of the SIC power module in real time under the DPWM modulation mode, thereby greatly reducing the system load rate. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] The disclosure of this application will become more easily understood with reference to the accompanying drawings. Those skilled in the art will readily appreciate that these drawings are merely for the purpose of illustrating this application and are not intended to limit the scope of protection of this application. Furthermore, similar numbers in the drawings represent similar components, where:

[0038] FIG1 is a flow chart showing the main steps of a method for determining SIC power module loss according to an embodiment of the present application;

[0039] FIG2 is a circuit topology diagram of a SIC power module in an embodiment of the present application;

[0040] FIG3 is a diagram showing the relationship between the DPWM modulation function and the current output by the SIC power module under electric operation in an embodiment of the present application;

[0041] FIG4 is a schematic diagram of a SIC loss model based on DPWM modulation in an embodiment of the present application. DETAILED DESCRIPTION

[0042] Some embodiments of the present application are described below with reference to the accompanying drawings. Those skilled in the art should understand that these embodiments are only used to explain the technical principles of the present application and are not intended to limit the scope of protection of the present application.

[0043] In the description of this application, "module" and "processor" may include hardware, software, or a combination of both. A module may include hardware circuitry, various suitable sensors, communication ports, and memory. It may also include software components, such as program code, or a combination of software and hardware. A processor may be a central processing unit, a microprocessor, an image processor, a digital signal processor, or any other suitable processor. A processor has data and / or signal processing capabilities. A processor may be implemented in software, hardware, or a combination of both. Non-transitory computer-readable storage media include any suitable medium capable of storing program code, such as magnetic disks, hard disks, optical disks, flash memory, read-only memory, random access memory, etc. The term "A and / or B" refers to all possible combinations of A and B, such as only A, only B, or both A and B. The terms "at least one of A or B" or "at least one of A and B" have similar meanings to "A and / or B" and may include only A, only B, or both A and B. The singular forms "one" and "the" may also include the plural forms.

[0044] During DPWM modulation, since its modulation wave is a discontinuous function, although the DPWM modulation wave can be decomposed into a series of sine waves of different frequencies and amplitudes through Fourier decomposition, it contains complex harmonic components. Existing technologies do not yet have a loss determination model suitable for running in real-time embedded systems. If the loss is calculated in real time within the PWM cycle and averaged over one electrical cycle, the system load rate will be greatly increased.

[0045] To this end, the present application provides a real-time calculation of the SIC module loss model under DPWM modulation. This model is an average model based on the electrical cycle, which can calculate the real-time loss of the SIC power module based on an analytical formula and can be executed in systems with slower chip computing power, greatly reducing the system load rate and making it suitable for operation in embedded devices.

[0046] Based on the above ideas, the present application provides a method for determining the loss of a SIC power module, wherein the SIC power module operates in a DPWM modulation mode. As shown in FIG1 , the method for determining the loss of a SIC power module in the embodiment of the present application includes the following steps S101 to S103:

[0047] Step S101, obtaining current phase current information of the SIC power module, current bus voltage information of the SIC power module, and current power factor angle information of the SIC power module;

[0048] The power devices used in inverters or rectifiers can be IGBTs, SiCs, GaNs, and other types. These power modules all generate conduction and switching losses during operation. Different types of power devices have different distributions of conduction and switching losses across the switching device and its parallel diode. This is primarily reflected in the differences between silicon-based IGBTs and SiC-based MOSFETs. This embodiment uses SiC-based MOSFET modules as an example.

[0049] In this embodiment, the current phase current information may include a numerical value or expression that can reflect the current phase current size of the SIC power module; the current bus voltage information may include a numerical value or expression that can reflect the current bus voltage size of the SIC power module; the current power factor angle information may include a numerical value or expression that can reflect the current power factor angle size of the SIC power module.

[0050] Step S102, obtaining current modulation ratio information in the DPWM modulation mode;

[0051] Conventional DPWM control modes include DPWM0, DPWM1, DPWM2, DPWMMAX, and DPWMMIN. This embodiment is described by taking the most commonly used DPWM1 modulation suitable for unity power factor working conditions as an example.

[0052] In this embodiment, the current modulation ratio information may include a numerical value or an expression that can reflect the current modulation ratio in the DPWM modulation mode.

[0053] Step S103 : determining the current loss of the SIC power module based on the current phase current information, the current bus voltage information, the current power factor angle information, and the current modulation ratio information.

[0054] In order to reduce the amount of calculation when determining the loss of the SIC power module, thereby further reducing the requirements for system computing power, in this embodiment, there is a linear relationship between the current phase current information and the current loss of the SIC power module, between the current bus voltage information and the current loss of the SIC power module, and between the current modulation ratio information and the current loss of the SIC power module.

[0055] As shown in Figure 2, the SIC power module described in this embodiment includes multiple chip units for circuit on / off control. Figure 2 shows six of these chip units. The leads from the midpoint between the upper and lower bridge arms represent the three-phase currents A, B, and C output by the SIC power module, which are connected to the motor. Each chip unit includes a MOSFET switching device and a diode connected in parallel with the switching device.

[0056] To more accurately determine the current loss of the SIC power module, the determining of the current loss of the SIC power module based on the current phase current information, the current bus voltage information, the current power factor angle information, and the current modulation ratio information in this embodiment includes: determining the current losses of all switching devices in the SIC power module based on the current phase current information, the current bus voltage information, the current power factor angle information, and the current modulation ratio information; and determining the current loss of the SIC power module based on the current losses of all switching devices.

[0057] To more accurately determine the current losses of all switching devices in the SIC power module, the determining of the current losses of all switching devices in the SIC power module based on the current phase current information, the current bus voltage information, the current power factor angle information, and the current modulation ratio information in this embodiment includes: determining the current conduction losses of all switching devices in the SIC power module based on the current phase current information, the current power factor angle information, and the current modulation ratio information; determining the current switching losses of all switching devices in the SIC power module based on the current phase current information, the current bus voltage information, and the current power factor angle information; and determining the current losses of all switching devices in the SIC power module based on the current conduction losses of all switching devices and the current switching losses of all switching devices.

[0058] As shown in Figure 2, taking a single phase of an SIC as an example, when a positive current is applied, the upper-side switching device, the MOSFET, switches. When the upper-side switching device is on, current flows through it, generating conduction losses due to the MOSFET's conduction voltage drop. When the upper-side MOSFET is off, current flows through the lower-side switching device, the MOSFET, generating conduction losses due to the MOSFET's conduction voltage drop. The same applies when a negative current is applied. During the switching process of the MOSFET, there is an overlap between the current and voltage across the switching device, resulting in losses. This loss is referred to as switching loss.

[0059] In practical applications, the MOSFET body diode only experiences conduction losses during the dead time. During this dead time, the MOSFET body diode performs the freewheeling function. When the dead time expires, the MOSFET turns on, switching the current to the MOSFET channel. Because the MOSFET dead time is extremely short, the conduction losses of the diode can be ignored. Furthermore, due to the bidirectional conduction characteristics of the MOSFET, the switching losses of the diode in the SIC power module can be approximately considered to be zero. Therefore, this embodiment determines the losses of the SIC power module based solely on the conduction and switching losses of the MOSFET switching device, without considering the conduction and switching losses of the diode.

[0060] Specifically, this embodiment can divide the current loss of the switching device into two categories: the current conduction loss of the switching device and the current switching loss of the switching device. After calculating the current conduction loss of all switching devices and the current switching loss of all switching devices respectively, the current loss of all switching devices can be determined based on these two categories of losses.

[0061] In this embodiment, the current phase current information includes the current phase current amplitude; the current power factor angle information includes the current power factor angle; and the current modulation ratio information includes the current modulation ratio. That is, in this embodiment, the current specific values ​​of each electrical parameter can be used to reflect the electrical parameter information. Under this premise, in order to more accurately determine the current conduction loss of all switching devices in the SIC power module, the present embodiment determines the current conduction loss of all switching devices in the SIC power module based on the current phase current information, the current power factor angle information, and the current modulation ratio information, including: inputting the current phase current amplitude, the current power factor angle, and the current modulation ratio into a pre-established first expression, so that the first expression outputs the current conduction loss of each switching device; wherein the first expression is pre-established based on the relationship between the current phase current amplitude, the current power factor angle, the current modulation ratio, the ratio of the on-resistance of each switching device, the bias value of the on-resistance of each switching device, and the current conduction loss of each switching device, and the ratio and the bias value are both constants; and calculating the sum of the current conduction loss of each switching device to obtain the current conduction loss of all switching devices in the SIC power module.

[0062] In order to further reduce the amount of calculation, in this embodiment, there is a linear relationship between the current phase current amplitude and the current conduction loss of each switching device, and between the current modulation ratio and the current conduction loss of each switching device.

[0063] In a specific embodiment, the first expression is:

[0064] Among them, P MosConLoss(DPWM1) is the single MOSFET conduction loss, i.e., the current conduction loss of a switch device in the SIC power module; I m is the current phase current amplitude; b is the bias value of the on-resistance of each switching device, which is a constant; k is the ratio of the on-resistance of each switching device, which is a constant; M is the current modulation ratio; is the current power factor angle.

[0065] After the current conduction loss of each switching device is calculated using the above formula, the current conduction loss of all switching devices in the SIC power module can be calculated by summing them.

[0066] In this embodiment, the current phase current information includes: the current phase current amplitude; the current bus voltage information includes: the current bus voltage; the current power factor angle information includes: the current power factor angle. That is, in this embodiment, the current specific numerical value of each electrical parameter can be used to reflect the information of each electrical parameter. Under this premise, in order to more accurately determine the current switching loss of all switching devices in the SIC power module, the current switching loss of all switching devices in the SIC power module is determined based on the current phase current information, the current bus voltage information and the current power factor angle information, including: inputting the current phase current amplitude, the current bus voltage and the current power factor angle into a pre-constructed second expression, so that the second expression outputs the current switching loss of each switching device; wherein, the second expression is based on the current phase current amplitude, the current bus voltage, the current power factor A relationship between the magnitude of the digital angle, the switching frequency of each switching device, the energy consumed when each switching device is turned on once, the energy consumed when each switching device is turned off once, the bus reference voltage value of the SIC power module, the reference current value output by the SIC power module, and the current switching loss of each switching device is pre-established, and the switching frequency, the energy consumed when each switching device is turned on once, the energy consumed when each switching device is turned off once, the bus reference voltage value, and the reference current value are all constants; the sum of the current switching losses of each switching device is calculated to obtain the current switching losses of all switching devices in the SIC power module.

[0067] In order to further reduce the amount of calculation, in this embodiment, there is a linear relationship between the current phase current amplitude and the current switching loss of each switching device, and between the current bus voltage and the current switching loss of each switching device.

[0068] In a specific embodiment, the second expression is:

[0069] Among them, P MosSwLoss(DPWM1) is the single MOSFET switching loss, i.e., the current switching loss of a switching device in the SIC power module; I m is the current phase current amplitude; U dc is the current bus voltage; is the current power factor angle; f sw is the switching frequency of each switching device, which is a constant; E SICon The energy consumed when each switch is turned on is a constant; E SICoff The energy consumed when each switching device is turned off once is a constant; Un is the bus reference voltage value, which is a constant; I n is the reference current value, which is a constant.

[0070] After the current switching loss of each switching device is calculated using the above formula, the current switching losses of all switching devices in the SIC power module can be calculated by summing them.

[0071] To more accurately determine the current losses of all switching devices in the SIC power module, the present embodiment determines the current losses of all switching devices in the SIC power module based on the current conduction losses and the current switching losses of all switching devices, including calculating the sum of the current conduction losses of all switching devices and the current switching losses of all switching devices to obtain the current losses of all switching devices in the SIC power module.

[0072] In order to more accurately determine the current loss of the SIC power module, the determining of the current loss of the SIC power module based on the current losses of all the switching devices in this embodiment includes: obtaining the current losses of all the switching devices as the current loss of the SIC power module.

[0073] Furthermore, in order to more comprehensively determine the loss of the SIC power module, the method described in this embodiment also includes: determining the current conduction loss of all switching devices in the SIC power module based on the current phase current information, the current power factor angle information, and the current modulation ratio information; and determining the current total conduction loss of the SIC power module based on the current conduction loss of all switching devices.

[0074] Among them, the specific method for determining the current conduction loss of all switching devices in the SIC power module can be found in the technical solution described above, and will not be repeated here.

[0075] In this embodiment, after the current conduction losses of all switching devices in the SIC power module are determined, the current conduction losses of all switching devices in the SIC power module may be used as the current total conduction losses of the SIC power module.

[0076] Furthermore, in order to more comprehensively determine the loss of the SIC power module, the method described in this embodiment also includes: determining the current switching loss of all switching devices in the SIC power module based on the current phase current information, the current bus voltage information, and the current power factor angle information; and determining the current total switching loss of the SIC power module based on the current switching losses of all switching devices.

[0077] The specific method for determining the current switching losses of all switching devices in the SIC power module can be found in the technical solution described above and will not be described in detail here.

[0078] In this embodiment, after the current switching losses of all switching devices in the SIC power module are determined, the current switching losses of all switching devices in the SIC power module can be used as the current total switching loss of the SIC power module.

[0079] The following describes the derivation process and derivation principle of the first and second expressions above:

[0080] The DPWM1 modulation function is discontinuous, with two 60° periods of inactive switching within one electrical cycle. Using Fourier decomposition to determine its modulation function expression is cumbersome. This embodiment first uses piecewise function integration to obtain its analytical expression, which is then used to calculate the losses of the SIC power module. The DPWM1 modulation function expression within one cycle (0 to 2π) is as follows:

[0081] Where θ is the electrical angle of the motor, that is, the angle between the motor rotor N axis and the stator A axis; M is the modulation ratio under DPWM1 modulation; is the power factor angle of the SIC power module.

[0082] In this embodiment, the MOSFET and diode losses under DPWM1 modulation can be solved by a piecewise integration and simplification method.

[0083] 1. Calculation of conduction loss under DPWM1 modulation

[0084] The relationship between the DPWM modulation function and the current output by the SIC power module under electric working conditions is shown in Figure 3. From Figure 3, we can see the phase relationship between the current and voltage duty cycle. The curve DutyA DPWM1 can be divided into six segments, corresponding to the above Duty DPWM1 The six-segment expression in (θ). The electrical parameters in Figure 3 are: modulation ratio M = 0.8, phase current amplitude I m =100,\varphi=\frac{\pi}{12}.

[0085] In this embodiment, since the MOSFET conducts current in both positive and negative current cycles, the integration period for the conduction loss calculation is 2π. Also, since the motoring and generating conditions are symmetrical, there is no need to distinguish between the motoring and generating conditions in the conduction loss calculation of the SIC.

[0086] For SIC MOSFET, the voltage between the DS poles and the current flowing through the curve pass through the zero point, and there is no initial turn-on voltage value, that is, U ds=r mos *I

[0087] Among them, U ds is the voltage between the drain and source of the switching device MOSFET; r mos is the on-resistance of the switching device MOSFET; I is the phase current.

[0088] But the on-resistance of SIC MOSFET is r mos It is a current and temperature sensitive value. The relationship between the on-resistance of a certain SIC MOSFET and the current flowing through it at different junction temperatures is as follows. It can be approximately considered that: mos =k*I+b, where k and b are the on-resistance property parameters of the SIC MOSFET at a certain junction temperature and are fixed values.

[0089] The average conduction loss of a single switching device MOSFET in one electrical cycle can be calculated by summing up the seven integrals of the MOSFET conduction loss in one current cycle and averaging them. The specific formula is as follows:

[0090] Among them, P MosConLoss(DPWM1) is the conduction loss of a single MOSFET, i.e., the conduction loss of a switching device in the SIC power module; is the power factor angle of the power module; I m is the phase current amplitude of the power module; θ is the motor's electrical angle, that is, the angle between the motor's rotor axis N and the stator axis A; M is the modulation ratio in DPWM1 modulation mode; b is the bias value of the switching device's on-resistance; and k is the proportional value of the switching device's on-resistance. The number of steps in the above formula is determined by the voltage duty cycle. In DPWM1 modulation mode, the SIC power module has a voltage duty cycle with seven discontinuous regions. Therefore, the loss calculation is also divided into seven steps.

[0091] The MOSFET body diode only has conduction loss during the dead time. During the dead time period, the MOSFET body diode assumes the function of freewheeling. When the dead time period ends, the MOSFET is turned on and the current is switched to the MOSFET channel. Since the MOSFET dead time is extremely small, the conduction loss of the diode can be ignored, that is, P DiodeConLoss(DPWM1) =0

[0092] 2. Switching loss calculation under DPWM1 modulation

[0093] Since the switching losses in the motoring and generating modes are symmetrical, and the switching losses are the same in both modes, this embodiment only needs to list the formula for the motoring mode. The switching loss of a single switching device, MOSFET, can be calculated by summing the SIC switching loss in two integrals within half a current cycle. The specific formula is as follows:

[0094] Among them, P MosSwLoss(DPWM1) is the single MOSFET switching loss, i.e., the current switching loss of a switching device in the SIC power module; I m is the phase current amplitude of the power module; U dc is the bus voltage of the power module; is the power factor angle of the power module; f sw is the switching frequency of the switching device; E SICon The energy consumed by the switch when it is turned on once; E SICoff The energy consumed when the switch is turned off once; U n is the bus reference voltage value; I n is the reference current value output by the power module; θ is the electrical angle of the motor, that is, the angle between the motor rotor N axis and the stator A axis.

[0095] Due to the bidirectional conduction characteristics of MOSFET, the switching loss of the diode of the SIC module can be approximately considered to be 0, that is, P DiodeSirLoss(DPWM1) =0

[0096] 3. Analytical Expression of SIC Loss under DPWM1 Modulation

[0097] By performing a series of symbolic operations and simplifications on the above formulas, we can derive the final analytical expressions for conduction loss and switching loss, namely the first and second expressions mentioned above. The first and second expressions are analytical expressions of the integral results of the above integral formulas. In practical applications, no integral accumulation calculations are required, resulting in simple calculations, low system computing power consumption, and real-time execution in embedded systems.

[0098] (1) Conduction loss

[0099] The analytical expression for the conduction loss of a single MOSFET is:

[0100] Among them, P MosConLoss(DPWM1) is the single MOSFET conduction loss, i.e., the current conduction loss of a switch device in the SIC power module; I m is the current phase current amplitude; b is the bias value of the on-resistance of each switching device, which is a constant; k is the ratio of the on-resistance of each switching device, which is a constant; M is the current modulation ratio; is the current power factor angle.

[0101] Through the above analytical expression, the total conduction loss of the SIC power module can be calculated as: TotalConLoss(DPWM1) =6P MosConlos s (DPWM1)

[0102] (2) Switching loss

[0103] The analytical expression for the switching loss of a single MOSFET is:

[0104] Among them, P MosSwLoss(DPWM1) is the single MOSFET switching loss, i.e., the current switching loss of a switching device in the SIC power module; I m is the current phase current amplitude; U dc is the current bus voltage; is the current power factor angle; f sw is the switching frequency of each switching device, which is a constant; E SICon The energy consumed when each switch is turned on is a constant; E SICoff The energy consumed when each switching device is turned off once is a constant; U n is the bus reference voltage value, which is a constant; I n is the reference current value, which is a constant.

[0105] Through the above analytical expression, the total switching loss of the SIC power module can be calculated as: TotalConLoss(DPWM1) =6P MosConloss(DPWM1)

[0106] Through the above analytical expression, the single MOSFET loss can be calculated as: MosLoss(DPWM1) =P MosConLoss(DPWM1) +P MosSwLoss(DPWM1)

[0107] In this embodiment, the loss of a single diode is: DiodeLoss(DPWM1) =0

[0108] Through the above analytical expression, the total loss of the SIC power module under DPWM1 modulation can be calculated as: TotalLoss(DPWM1) =6[P MosLoss(DPWM1) +P DiodeLoss(DPWM1) ]

[0109] The SIC loss model under DPWM1 modulation is shown in Figure 4. By obtaining the current electrical parameter I m 、U dc 、 and M, inputting them into the loss model, we can get P TotalLoss(DPWM1) 、P IGBTLoss(DPWM1) and P DiodeLoss(DPWM1) The output result is:

[0110] This embodiment proposes an analytically expressed SIC loss model under DPWM control, including both a MOSFET / Diode conduction loss model and a MOSFET / Diode switching loss model. This model comprehensively determines the losses of the SIC power module. Furthermore, the analytical expression for MOSFET / Diode losses under DPWM1 modulation derived in this embodiment does not require distinguishing between motoring and generating conditions, resulting in minimal overall computing power consumption.

[0111] Based on steps S101-S103 above, this application solves the technical problem that the existing methods for determining the loss of SIC power modules under DPWM modulation are complex and computationally intensive, resulting in the inability to run in real time in systems with low computing power. Furthermore, this application proposes a SIC module loss model based on analytical expressions under DPWM modulation, which allows the model to run in real time in embedded systems and solves the problem that the existing DPWM modulation mode lacks a loss model based on analytical equations.

[0112] It should be pointed out that although the various steps in the above embodiments are described in a specific order, those skilled in the art will understand that in order to achieve the effect of the present application, different steps do not have to be performed in such an order. They can be performed simultaneously (in parallel) or in other orders. These changes are within the scope of protection of the present application.

[0113] The technical solution provided by the embodiment of the present application obtains the current phase current information, current bus voltage information, and current power factor angle information of the SIC power module, and obtains the current modulation ratio information under the DPWM modulation mode. Based on the above current phase current information, current bus voltage information, current power factor angle information, and current modulation ratio information, the current loss of the SIC power module is determined, so that the determination of the current loss of the SIC power module can be based on the current electrical parameters. That is, the present application can obtain the SIC power module loss corresponding to the moment based on the electrical parameters at any moment. Compared with the existing technology that requires the integration and accumulation of the loss of an electrical cycle, the present application can obviously determine the current loss of the power module more conveniently and timely. Moreover, the present application simultaneously determines the loss of the power module based on the current phase current information, current bus voltage information, current power factor angle information, and current modulation ratio information, comprehensively considering various electrical parameters that affect the loss of the power module, and thus can obtain accurate determination results. It can be seen that the technical solution provided by the embodiment of the present application can more conveniently and accurately determine the loss of the SIC power module in real time under the DPWM modulation mode, thereby greatly reducing the system load rate.

[0114] Furthermore, the present application also provides a SIC power module loss determination device, wherein the SIC power module operates in a DPWM modulation mode. The SIC power module loss determination device in the embodiment of the present application mainly includes a first acquisition unit, a second acquisition unit and a loss determination unit.

[0115] a first acquiring unit, configured to acquire current phase current information of the SIC power module, current bus voltage information of the SIC power module, and current power factor angle information of the SIC power module;

[0116] A second acquiring unit, configured to acquire current modulation ratio information in the DPWM modulation mode;

[0117] A loss determination unit is used to determine the current loss of the SIC power module based on the current phase current information, the current bus voltage information, the current power factor angle information and the current modulation ratio information.

[0118] In some embodiments, one or more of the first acquisition unit, the second acquisition unit, and the loss determination unit may be combined into one module. In one embodiment, the specific implementation functions thereof may be described in detail in steps S101 to S103.

[0119] The above-mentioned SIC power module loss determination device is used to execute the embodiment of the SIC power module loss determination method shown in Figure 1. The technical principles, technical problems solved, and technical effects produced by the two are similar. Those skilled in the art can clearly understand that for the convenience and brevity of description, the specific working process and related instructions of the SIC power module loss determination device can refer to the contents described in the embodiment of the SIC power module loss determination method, and will not be repeated here.

[0120] Furthermore, the present application also provides a computer-readable storage medium. In one embodiment of a computer-readable storage medium according to the present application, the computer-readable storage medium can be configured to store a program for executing the SIC power module loss determination method of the above-described method embodiment. The program can be loaded and executed by a processor to implement the above-described SIC power module loss determination method. For ease of illustration, only the portions related to the embodiments of the present application are shown. For specific technical details not disclosed, please refer to the method section of the embodiments of the present application. The computer-readable storage medium can be a storage device formed by various electronic devices. Optionally, the computer-readable storage medium in the embodiments of the present application is a non-transitory computer-readable storage medium.

[0121] Furthermore, the present application also provides a computer device, which includes a storage device and a processor, wherein the storage device stores program code that can be run on the processor, and when the program code is executed by the processor, the SIC power module loss determination method as described in any of the above-mentioned SIC power module loss determination method technical solutions is implemented.

[0122] In this embodiment, the storage device in the computer device may be configured to store a program for executing the method for determining SIC power module loss according to the above-described method embodiment, and the processor may be configured to execute the program in the storage device, including but not limited to a program for executing the method for determining SIC power module loss according to the above-described method embodiment. For ease of illustration, only portions relevant to the embodiment of the present invention are shown. For specific technical details not disclosed, please refer to the method section of the embodiment of the present invention.

[0123] In the embodiment of the present application, the computer device may be a control device formed by various electronic devices. In some possible implementations, the device may include multiple storage devices and multiple processors. The program for executing the SIC power module loss determination method of the above method embodiment can be divided into multiple subroutines, each of which can be loaded and run by a processor to execute different steps of the SIC power module loss determination method of the above method embodiment. Specifically, each subroutine can be stored in a different memory, and each processor can be configured to execute the program in one or more memories to jointly implement the SIC power module loss determination method of the above method embodiment, that is, each processor executes different steps of the SIC power module loss determination method of the above method embodiment to jointly implement the SIC power module loss determination method of the above method embodiment.

[0124] The aforementioned multiple processors may be processors deployed on the same device. For example, the aforementioned computer device may be a high-performance device composed of multiple processors, and the aforementioned multiple processors may be processors configured on the high-performance device. Furthermore, the aforementioned multiple processors may also be processors deployed on different devices. For example, the aforementioned computer device may be a server cluster, and the aforementioned multiple processors may be processors on different servers in the server cluster.

[0125] It will be understood by those skilled in the art that all or part of the processes in the method for implementing the above embodiment of the present application can also be completed by instructing the relevant hardware through a computer program. The computer program can be stored in a computer-readable storage medium. When the computer program is executed by a processor, it can implement the steps of each of the above method embodiments. The computer program includes computer program code, which can be in source code form, object code form, executable file or some intermediate form. The computer-readable storage medium can include: any entity or device, medium, USB flash drive, mobile hard disk, magnetic disk, optical disk, computer memory, read-only memory, random access memory, electric carrier signal, telecommunication signal and software distribution medium that can carry the computer program code. It should be noted that the content contained in the computer-readable storage medium can be appropriately increased or decreased according to the requirements of legislation and patent practice in the jurisdiction. For example, in some jurisdictions, according to legislation and patent practice, computer-readable storage media do not include electric carrier signals and telecommunication signals.

[0126] Thus far, the technical solutions of the present application have been described in conjunction with the preferred embodiments shown in the accompanying drawings. However, it is readily understood by those skilled in the art that the scope of protection of the present application is obviously not limited to these specific embodiments. Without departing from the principles of the present application, those skilled in the art may make equivalent changes or substitutions to the relevant technical features, and the technical solutions after such changes or substitutions will fall within the scope of protection of the present application.

Claims

1. A method for determining SIC power module loss, characterized in that: The SIC power module operates in a DPWM modulation mode; the method comprises: Acquire current phase current information of the SIC power module, current bus voltage information of the SIC power module, and current power factor angle information of the SIC power module; Acquire current modulation ratio information under the DPWM modulation mode; The current loss of the SIC power module is determined based on the current phase current information, the current bus voltage information, the current power factor angle information and the current modulation ratio information.

2. The method for determining the SIC power module loss according to claim 1, characterized in that: The SIC power module includes a plurality of chip units for performing circuit on-off control; each of the chip units includes: a switch device of type MOSFET, and a diode connected in parallel with the switch device; the current loss of the SIC power module is determined based on the current phase current information, the current bus voltage information, the current power factor angle information and the current modulation ratio information, including: Determine the current loss of all switching devices in the SIC power module based on the current phase current information, the current bus voltage information, the current power factor angle information and the current modulation ratio information; Based on the current losses of all the switching devices, the current losses of the SIC power module are determined.

3. The method for determining the SIC power module loss according to claim 2, characterized in that: The determining of the current losses of all switching devices in the SIC power module based on the current phase current information, the current bus voltage information, the current power factor angle information and the current modulation ratio information includes: Determining current conduction losses of all switching devices in the SIC power module based on the current phase current information, the current power factor angle information, and the current modulation ratio information; Determining current switching losses of all switching devices in the SIC power module based on the current phase current information, the current bus voltage information, and the current power factor angle information; Based on the current conduction losses of all the switching devices and the current switching losses of all the switching devices, current losses of all the switching devices in the SIC power module are determined.

4. The method for determining the SIC power module loss according to claim 3, characterized in that: The current phase current information includes: the current phase current amplitude; the current power factor angle information includes: the current power factor angle; the current modulation ratio information includes: the current modulation ratio; the current conduction loss of all switching devices in the SIC power module is determined based on the current phase current information, the current power factor angle information and the current modulation ratio information, including: Inputting the current phase current amplitude, the current power factor angle and the current modulation ratio into a pre-constructed first expression, so that the first expression outputs the current conduction loss of each of the switching devices; wherein the first expression is pre-constructed based on the relationship between the current phase current amplitude, the current power factor angle, the current modulation ratio, the ratio value of the on-resistance of each of the switching devices, the bias value of the on-resistance of each of the switching devices and the current conduction loss of each of the switching devices, and the ratio value and the bias value are both constants; The sum of the current conduction loss of each of the switching devices is calculated to obtain the current conduction loss of all the switching devices in the SIC power module.

5. The method for determining the SIC power module loss according to claim 3, characterized in that: The current phase current information includes: the current phase current amplitude; the current bus voltage information includes: the current bus voltage; the current power factor angle information includes: the current power factor angle; the current switching loss of all switching devices in the SIC power module is determined based on the current phase current information, the current bus voltage information and the current power factor angle information, including: Input the current phase current amplitude, the current bus voltage and the current power factor angle into a pre-constructed second expression, so that the second expression outputs the current switching loss of each switching device; wherein the second expression is pre-constructed based on the current phase current amplitude, the current bus voltage, the current power factor angle, the switching frequency of each switching device, the energy consumed when each switching device is turned on once, the energy consumed when each switching device is turned off once, the bus reference voltage value of the SIC power module, the reference current value output by the SIC power module and the current switching loss of each switching device, and the switching frequency, the energy consumed when each switching device is turned on once, the energy consumed when each switching device is turned off once, the bus reference voltage value and the reference current value are all constants; The sum of the current switching losses of each of the switching devices is calculated to obtain the current switching losses of all the switching devices in the SIC power module.

6. The method for determining the SIC power module loss according to claim 3, characterized in that: The determining the current losses of all the switching devices in the SIC power module based on the current conduction losses of all the switching devices and the current switching losses of all the switching devices comprises: The sum of the current conduction loss of all the switching devices and the current switching loss of all the switching devices is calculated to obtain the current loss of all the switching devices in the SIC power module.

7. The method for determining the SIC power module loss according to claim 2, characterized in that: The determining the current loss of the SIC power module based on the current loss of all the switching devices includes: The current losses of all the switching devices are obtained as the current losses of the SIC power module.

8. The method for determining SIC power module loss according to claim 1, characterized in that: The method further comprises: Determining current conduction losses of all switching devices in the SIC power module based on the current phase current information, the current power factor angle information, and the current modulation ratio information; Based on the current conduction losses of all the switch devices, a current total conduction loss of the SIC power module is determined.

9. The SIC power module loss determination method according to claim 1, characterized in that: The method further comprises: Determining current switching losses of all switching devices in the SIC power module based on the current phase current information, the current bus voltage information, and the current power factor angle information; Based on the current switching losses of all the switching devices, a current total switching loss of the SIC power module is determined.

10. A computer-readable storage medium storing a plurality of program codes, characterized in that: The program code is suitable for being loaded and run by a processor to execute the SIC power module loss determination method according to any one of claims 1 to 9.

11. A computer device, characterized in that: The computer device includes a storage device and a processor, wherein the storage device stores a program code that can be run on the processor, and when the program code is executed by the processor, the SIC power module loss determination method according to any one of claims 1 to 9 is implemented.

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