Method, device and equipment for calculating loss power of inverter and storage medium

Abstract

The invention provides a loss power calculation method and device of an inverter, equipment and a storage medium. The loss power calculation method of the inverter comprises the following steps: acquiring a three-phase modulation wave and a three-phase current of the inverter in a first switching period based on a preset general motor algorithm control model; calculating the switching loss of the inverter in the first switching period according to the three-phase current and a preset first corresponding relation; calculating the conduction loss of the inverter in the first switching period according to the three-phase modulation wave and the three-phase current; and calculating the loss power of the inverter according to the conduction loss and the switching loss. According to the method, the three-phase modulation wave and the three-phase current can be determined only by using a general simple model, the loss power can be calculated according to the three-phase current and the three-phase modulation wave, the method does not need to establish an accurate model of the inverter for simulation to obtain complex data, the calculation method of the loss power is simplified, and the calculation efficiency is improved. And the efficiency of calculating the loss power of the inverter is improved.

Description

Technical Field

[0001] The present application relates to the field of electronic technology, and in particular to a method, device, equipment and storage medium for calculating power loss of an inverter. Background Art

[0002] An inverter is an electronic device that converts direct current into alternating current, which can be used for motor traction. Currently, it is often necessary to calculate the power loss of the inverter in order to better optimize the inverter.

[0003] In the prior art, the calculation of the inverter power loss requires the establishment of an accurate inverter model for the inverter and continuous integral calculation of the inverter working process; or the calculation is performed based on the parameters of the power devices in the inverter and the modulation ratio, power factor, current, switching frequency and other data obtained by simulation. It is difficult to establish an accurate model of the inverter with the prior art, which is not conducive to the rapid assessment of the power device loss. Secondly, the existing method of obtaining the power device parameters and simulation results based on the accurate model requires obtaining the modulation ratio, power factor, switching frequency and other results, and the calculation process is complicated. It is also not conducive to the rapid assessment of the inverter power loss. Summary of the invention

[0004] In view of this, the purpose of the present application is to provide a method, device, equipment and storage medium for calculating the power loss of an inverter, which simplifies the method for calculating the power loss and improves the efficiency of calculating the power loss of the inverter.

[0005] To achieve the above objectives, the present application discloses the following technical solutions:

[0006] In a first aspect, the present application provides a method for calculating power loss of an inverter, comprising:

[0007] Acquire the three-phase modulation wave and three-phase current of the inverter in the first switching cycle based on a preset universal motor algorithm control model;

[0008] Calculating the switching loss of the inverter in the first switching period according to the three-phase current and a preset first corresponding relationship, wherein the first corresponding relationship includes a corresponding relationship between the three-phase current and the switching loss;

[0009] Calculating the conduction loss of the inverter in the first switching period according to the three-phase modulation wave and the three-phase current;

[0010] The power loss of the inverter in the first switching period is calculated according to the conduction loss and the switching loss.

[0011] Optionally, the inverter includes a power device and an anti-parallel diode, and the method further includes: acquiring a first on-resistance of the power device, a second on-resistance of the anti-parallel diode, a period of a preset carrier, and a dead time;

[0012] The calculating the conduction loss of the inverter in the first switching period according to the three-phase modulation wave and the three-phase current includes:

[0013] Determining the conduction time of the bridge arm of the inverter according to the three-phase modulation wave, the period of the preset carrier and the dead time;

[0014] The conduction loss of the inverter in the first switching period is calculated according to the conduction time, the three-phase current, the first conduction resistance and the second conduction resistance.

[0015] Optionally, the on-time includes a first on-time of an upper bridge arm and a second on-time of a lower bridge arm;

[0016] Determining the conduction time of each bridge arm of the inverter according to the three-phase modulation wave, the period of the preset carrier and the dead time, including: determining the first conduction time according to the three-phase modulation wave and the period of the preset carrier; determining the second conduction time according to the first conduction time, the period of the preset carrier and the dead time;

[0017] Then, calculating the conduction loss of the inverter in the first switching period according to the conduction time, the three-phase current, the first conduction resistance and the second conduction resistance includes:

[0018] The conduction loss of the inverter in the first switching period is calculated according to the three-phase current, the first conduction time, the second conduction time, the first conduction resistance, the period of the preset carrier and the second conduction resistance.

[0019] Optionally, the method further includes:

[0020] The power device generating the switching loss and / or the conduction loss and the anti-parallel diode generating the switching loss and / or the conduction loss are determined according to the positive and negative information of the three-phase current.

[0021] Optionally, when the positive and negative information of the three-phase current is greater than zero, the conduction loss is generated in the first power device and the second anti-parallel diode; the conduction loss of the inverter in the first switching cycle includes: the conduction loss generated by the first power device and the conduction loss generated by the second anti-parallel diode;

[0022] The calculating the conduction loss of the inverter in the first switching period according to the three-phase current, the first conduction time, the second conduction time, the first conduction resistance, the period of the preset carrier and the second conduction resistance includes:

[0023] Calculating according to the three-phase current, the first conduction time, and a first conduction resistance corresponding to the first power device to obtain a conduction loss generated by the first power device;

[0024] Calculating according to the three-phase current, the first conduction time, the period of the preset carrier, and the second on-resistance corresponding to the second anti-parallel diode to obtain the conduction loss generated by the second anti-parallel diode;

[0025] The conduction loss of the inverter in the first switching period is calculated based on the conduction loss generated by the first power device and the conduction loss generated by the second anti-parallel diode.

[0026] Optionally, when the positive and negative information of the three-phase current is less than zero, the conduction loss is generated in the second power device and the first anti-parallel diode; the conduction loss of the inverter in the first switching cycle includes: the conduction loss generated by the second power device and the conduction loss generated by the first anti-parallel diode;

[0027] The calculating the conduction loss of the inverter in the first switching period according to the three-phase current, the first conduction time, the second conduction time, the first conduction resistance, the period of the preset carrier and the second conduction resistance includes:

[0028] Calculating according to the three-phase current, the second conduction time, and the first on-resistance corresponding to the second power device to obtain a conduction loss generated by the second power device;

[0029] Calculating according to the three-phase current, the second conduction time, the period of the preset carrier, and the second conduction resistance corresponding to the first anti-parallel diode to obtain the conduction loss generated by the first anti-parallel diode;

[0030] The conduction loss of the inverter in the first switching period is obtained by calculating according to the conduction loss generated by the second power device and the conduction loss generated by the first anti-parallel diode.

[0031] Optionally, the switching loss includes a turn-on loss, a turn-off loss, and a reverse recovery loss, the first corresponding relationship includes a correspondence between the three-phase current and the turn-on loss, the turn-off loss, and the reverse recovery loss, respectively, and the switching loss of the inverter in the first switching period is calculated according to the three-phase current and the preset first corresponding relationship, including:

[0032] Determine, according to the three-phase current and the first corresponding relationship, a turn-on loss and a turn-off loss generated by the power device, and a reverse recovery loss generated by the anti-parallel diode;

[0033] The switching loss is determined according to the turn-on loss, the turn-off loss and the reverse recovery loss.

[0034] In a second aspect, the present application provides a device for calculating power loss of an inverter, the device comprising:

[0035] An acquisition unit, used for acquiring a three-phase modulation wave and a three-phase current of the inverter in a first switching cycle based on a preset universal motor algorithm control model;

[0036] a calculation unit, configured to calculate the switching loss of the inverter in the first switching period according to the three-phase current and a preset first corresponding relationship, wherein the first corresponding relationship includes a corresponding relationship between the three-phase current and the switching loss;

[0037] The calculation unit is further used to calculate the conduction loss of the inverter in the first switching period according to the three-phase modulation wave and the three-phase current;

[0038] The calculation unit is further used to calculate the power loss of the inverter in the first switching period according to the conduction loss and the switching loss.

[0039] In a third aspect, the present application provides a power loss device of an inverter, comprising:

[0040] Memory for storing computer programs;

[0041] A processor is used to execute the computer program stored in the memory to implement the steps of the inverter power loss calculation method provided in the first aspect.

[0042] In a fourth aspect, the present application provides a computer-readable storage medium having a computer program stored thereon, the computer program being executed by a processor to implement the steps of the method for calculating power loss of the inverter provided in the first aspect.

[0043] The present application provides a method, device, equipment and storage medium for calculating the power loss of an inverter. In a method for calculating the power loss of an inverter, the three-phase modulation wave and the three-phase current of the inverter in the first switching cycle are obtained based on a preset general motor algorithm control model; the switching loss of the inverter in the first switching cycle is calculated according to the three-phase current and a preset first corresponding relationship, and the first corresponding relationship includes the corresponding relationship between the three-phase current and the switching loss; the conduction loss of the inverter in the first switching cycle is calculated according to the three-phase modulation wave and the three-phase current; the power loss of the inverter is calculated according to the conduction loss and the switching loss. The present application only needs to use a general simple model to determine the three-phase modulation wave and the three-phase current, and the power loss calculation can be realized according to the three-phase current and the three-phase modulation wave. This method does not need to establish an accurate model of the inverter for simulation to obtain complex data, simplifies the method for calculating the power loss, and improves the efficiency of the power loss calculation of the inverter. BRIEF DESCRIPTION OF THE DRAWINGS

[0044] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0045] Figure 1 It is a flow chart of a method for calculating power loss of an inverter provided in an embodiment of the present application;

[0046] Figure 2 is a schematic diagram of a phase arm structure of an inverter provided in an embodiment of the present application;

[0047] Figure 3 It is a schematic diagram of a modulation wave and a carrier wave during modulation provided by an embodiment of the present application;

[0048] Figure 4 is a schematic diagram of a first corresponding relationship provided by the present application;

[0049] Figure 5 It is a schematic diagram of another flow chart of power loss calculation of an inverter provided by the present application;

[0050] Figure 6 It is a structural schematic diagram of a power loss calculation device for an inverter provided in an embodiment of the present application. DETAILED DESCRIPTION

[0051] In order to make the purpose, technical solution and advantages of the embodiments of the present application clearer, the technical solution in the embodiments of the present application will be clearly and completely described below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of this application.

[0052] To facilitate understanding of the technical solution provided by the present application, a method for calculating the power loss of an inverter provided by the present application will be described below in conjunction with the accompanying drawings. Figure 1 , which is a flow chart of a method for calculating power loss of an inverter provided in an embodiment of the present application, such as Figure 1 As shown, the method includes S101-S104.

[0053] S101: Acquire a three-phase modulation wave and a three-phase current of the inverter in the first switching cycle based on a preset universal motor algorithm control model.

[0054] In the embodiment of the present application, the three-phase modulation wave and the three-phase current of the inverter in the first switching cycle are obtained based on the preset universal motor algorithm control model. It can be understood that the universal motor algorithm control model can be an ideal model in the simulation software. The present application does not limit the setting method of the universal motor algorithm control model. As an example, the present application can establish a universal motor algorithm control model through methods such as id=0 control method, maximum torque current ratio control method, table lookup method, optimal efficiency control method, etc.

[0055] It can be understood that the first switching cycle refers to any switching cycle, and the specific time of a switching cycle can be determined according to the modulation requirements.

[0056] The present application does not limit the specific method of obtaining the three-phase modulation wave and the three-phase current based on the preset universal motor algorithm control model. As an example, the present application can obtain the reference speed and reference torque of the motor, and by inputting the reference speed and reference torque into the universal motor algorithm control model, the three-phase modulation wave and the three-phase current output by the universal motor algorithm control model are obtained.

[0057] It is understandable that the inverter is used for traction motor, and the present application can determine the three-phase modulation wave and three-phase current of the inverter by inputting the reference speed and reference torque of the motor. The present application does not limit the size of the reference speed and reference torque, and the size of the reference speed and reference torque can be determined according to actual conditions.

[0058] S102: Calculating the switching loss of the inverter in the first switching cycle according to the three-phase currents and a preset first corresponding relationship, where the first corresponding relationship includes a corresponding relationship between the three-phase currents and the switching loss.

[0059] It can be understood that switching loss refers to the loss generated during the switching process.

[0060] In the embodiment of the present application, after obtaining the three-phase current and the preset first corresponding relationship, the switching loss of the inverter in the first switching cycle can be calculated according to the three-phase current and the preset first corresponding relationship. It can be understood that the present application can obtain the corresponding relationship between the three-phase current and the switching loss from the data sheet of the inverter in advance, so as to pre-establish the first corresponding relationship.

[0061] The present application does not limit the specific method of calculating the switching loss of the inverter in the first switching period according to the three-phase current and the preset first corresponding relationship, which is specifically explained below.

[0062] S103: Calculate the conduction loss of the inverter in the first switching cycle according to the three-phase modulation wave and the three-phase current.

[0063] It is understandable that conduction loss refers to the situation in an electronic device or circuit where, when current passes through the conduction channel of a device, the on-resistance of the device is not zero, causing the current to generate a voltage drop across the on-resistance, thereby generating heat loss. In an embodiment of the present application, after obtaining the three-phase modulation wave and the three-phase current, the conduction loss of the inverter in the first switching cycle can be calculated based on the three-phase modulation wave and the three-phase current. The present application does not limit the specific method of calculating the conduction loss of the inverter in the first switching cycle based on the three-phase modulation wave and the three-phase current, which is specifically described below.

[0064] The present application does not limit the execution order of S102 and S103. The present application may execute S102 first and then S103, or execute S103 first and then S102, or execute S102 and S103 simultaneously.

[0065] S104: Calculate the power loss of the inverter in the first switching cycle according to the conduction loss and the switching loss.

[0066] In the embodiment of the present application, after the conduction loss and switching loss of the first switching cycle are determined, the power loss of the inverter in the first switching cycle is calculated based on the conduction loss and switching loss of the first switching cycle. As a possible implementation, the present application can add the conduction loss to the switching loss to obtain the total loss in a switching cycle, and then use the ratio of the total loss to the switching cycle as the power loss of the first switching cycle.

[0067] Through the above method, the present application only needs to use a general simple model to determine the three-phase modulation wave and the three-phase current, and the power loss calculation can be realized according to the three-phase current and the three-phase modulation wave. Compared with the prior art, the present application does not need to establish an accurate model of the inverter, nor does it need to obtain the complex parameters of the inverter to obtain the modulation ratio, power factor, current, and switching frequency to calculate the power loss, which simplifies the calculation method of the power loss and improves the efficiency of the inverter power loss calculation.

[0068] As a possible implementation method, the inverter includes a power device and an anti-parallel diode. The present application provides a method for calculating the power loss of the inverter, which also includes: obtaining the first on-resistance of the power device, the second on-resistance of the anti-parallel diode, the period of the preset carrier and the dead time.

[0069] The first on-resistance of the power device and the second on-resistance of the anti-parallel diode in the present application can also be obtained from the data sheet of the inverter. The period and dead time of the preset carrier can be obtained according to the specific modulation method. It can be understood that the inverter in the present application can be composed of a power device and an anti-parallel diode, such as Figure 2 As shown, Figure 2 A schematic diagram of a phase arm structure of an inverter provided in the present application, the phase arm structure is one phase in a three-phase two-level inverter topology structure, and the other two phases are the same. It can be understood that in the present application, one phase can have two power devices and two anti-parallel diodes. Figure 2 In the figure, T1 and T2 represent two different power devices, and D1 and D2 represent two different anti-parallel diodes, respectively. T1 and D1 form an upper bridge arm, and T2 and D2 form a lower bridge arm.

[0070] Then, in S103, the conduction loss of the inverter in the first switching cycle is calculated according to the three-phase modulation wave and the three-phase current, including the following steps A1-A2:

[0071] A1: Determine the conduction time of the bridge arm of the inverter according to the three-phase modulation wave, the period of the preset carrier and the dead time.

[0072] It can be understood that the dead time refers to the delay of opening the lower bridge arm after the upper bridge arm is turned off, or the delay of opening the upper bridge arm after the lower bridge arm is turned off, so as to avoid burning of power components. This delay time is the dead time.

[0073] The present application does not limit the determination of the conduction time of each bridge arm of the inverter according to the three-phase modulation wave, the period of the preset carrier and the dead time, which is specifically explained below.

[0074] A2: Calculate the conduction loss of the inverter in the first switching cycle according to the conduction time, the three-phase current, the first conduction resistance and the second conduction resistance.

[0075] In the embodiment of the present application, after the on-time is determined, the conduction loss of the inverter in the first switching cycle can be calculated according to the three-phase current, the first on-resistance and the second on-resistance. As an example, the present application can obtain the conduction loss of the inverter by first summing the first on-resistance and the second on-resistance, and multiplying the summed resistance value by the on-time and the three-phase current.

[0076] As another example, the conduction time includes a first conduction time of the upper bridge arm and a second conduction time of the lower bridge arm. The present application needs to calculate the first conduction time and the second conduction time first and then calculate the conduction loss of the inverter based on the first conduction time and the second conduction time. Specifically, in A1, the conduction time of each bridge arm of the inverter is determined according to the three-phase modulation wave, the period of the preset carrier and the dead time, including: determining the first conduction time according to the three-phase modulation wave and the period of the preset carrier; determining the second conduction time according to the first conduction time, the period of the preset carrier and the dead time.

[0077] It is understandable that the present application can determine the conduction time of each bridge arm based on different modulation methods, for example, by studying the law of loss generation of seven-segment space vector pulse width modulation (SVPWM) modulation, such as Figure 3 As shown, Figure 3 A schematic diagram of a modulation wave and a carrier during modulation provided in an embodiment of the present application, wherein the preset carrier is a triangular carrier, whose period is the switching period Ts, and the height is Ts / 2. The on-time calculated in the present application includes the first on-time of the upper bridge arm and the second on-time of the lower bridge arm. The present application can determine the state of the bridge arm by comparing the size of the modulation wave and the carrier. According to the characteristics of the seven-segment SVPWM modulation, the bridge arm must switch the switching state twice in one switching cycle. 0 represents that the upper bridge arm is turned off and the lower bridge arm is turned on, and 1 represents that the upper bridge arm is turned on and the lower bridge arm is turned off. When the modulation wave Tcm is greater than the carrier Ts, the bridge arm state is 0, and when the modulation wave is less than the carrier, the bridge arm state is 1.

[0078] Therefore, in one switching cycle, the first on-time of the upper bridge arm can be calculated by the following formula (1). The second on-time of the lower bridge arm can be calculated by the following formula (2).

[0079] Ton1 = Ts - 2Tcm (1);

[0080] Ton2 = Ts - Ton1 - 2Td (2);

[0081] Among them, Ton1 represents the first conduction time of the upper bridge arm, Ton2 represents the second conduction time of the lower bridge arm, Ts represents the period of the preset carrier, Tcm represents the three-phase modulation wave, and Td represents the dead time.

[0082] Then A2 determines the conduction loss of the inverter according to the conduction time, three-phase current, the first conduction resistance and the second conduction resistance, including: determining the conduction loss of the inverter according to the three-phase current, the first conduction time, the second conduction time, the first conduction resistance, the period of the preset carrier and the second conduction resistance.

[0083] The present application does not limit the specific calculation method for determining the conduction loss of the inverter based on the three-phase current, the first conduction time, the second conduction time, the first on-resistance, the period of the preset carrier and the second on-resistance. As an example, the present application can also combine the positive and negative information of the three-phase current to jointly determine the conduction loss of the inverter.

[0084] The present application can make the distinction as a possible implementation method. The present application provides a method for calculating the power loss of an inverter, which also includes: determining the power device that generates switching loss and / or conduction loss, and the anti-parallel diode that generates switching loss and / or conduction loss based on the positive and negative information of the three-phase current.

[0085] It can be understood that the present application can determine the current direction based on the positive and negative information of the three-phase current, thereby further determining the power devices and anti-parallel diodes that generate conduction losses, and can obtain the devices where the losses occur, making it easier to observe the loss distribution.

[0086] As a possible implementation method, when the positive and negative information of the three-phase current is greater than zero, conduction loss is generated in the first power device and the second anti-parallel diode; the conduction loss of the inverter in the first switching cycle includes: the conduction loss generated by the first power device and the conduction loss generated by the second anti-parallel diode.

[0087] It can be understood that the positive and negative information of the three-phase current includes greater than zero and less than zero. The present application can determine which device generates conduction loss based on the positive and negative information of the three-phase current. Figure 2 Taking the middle phase arm as an example, in the present application, the first power device may be T1, the second power device may be T2, the first anti-parallel diode may be D1, and the second anti-parallel diode may be D2. When the three-phase current is greater than zero and the bridge arm state is 0, conduction loss is generated on the second anti-parallel diode D2; when the three-phase current is greater than zero and the bridge arm state is 1, conduction loss is generated on the first power device T1.

[0088] The conduction loss of the inverter in the first switching period is calculated according to the three-phase current, the first conduction time, the second conduction time, the first conduction resistance, the period of the preset carrier and the second conduction resistance, including:

[0089] B1: Calculate according to the three-phase current, the first conduction time, and the first conduction resistance corresponding to the first power device to obtain the conduction loss generated by the first power device.

[0090] In the embodiment of the present application, the conduction loss generated by the first power device can be calculated according to the following formula: i^2*Rdson_MOS*Ton1;

[0091] In the formula, i represents the three-phase current, Rdson_MOS represents the first on-resistance corresponding to the first power device, and Ton1 represents the first on-time.

[0092] B2: Calculating according to the three-phase current, the first conduction time, the period of the preset carrier, and the second conduction resistance corresponding to the second anti-parallel diode to obtain the conduction loss generated by the second anti-parallel diode;

[0093] In the embodiment of the present application, the conduction loss generated by the second anti-parallel diode can be calculated according to the following formula: i^2*Rdson_Diode*(Ts-Ton1);

[0094] In the formula, i represents the three-phase current, Rdson_Diode represents the second on-resistance corresponding to the second anti-parallel diode, Ts represents the period of the preset carrier, and Ton1 represents the first on-time.

[0095] B3: Calculate the conduction loss of the inverter in the first switching period according to the conduction loss generated by the first power device and the conduction loss generated by the second anti-parallel diode.

[0096] In the present application, the conduction loss generated by the first power device and the conduction loss generated by the second anti-parallel diode may be added together to obtain the conduction loss of the inverter in the first switching cycle.

[0097] As another possible implementation method, when the positive and negative information of the three-phase current is less than zero, the conduction loss is generated in the second power device and the first anti-parallel diode; the conduction loss of the inverter in the first switching cycle includes: the conduction loss generated by the second power device and the conduction loss generated by the first anti-parallel diode.

[0098] In the present application, when the three-phase current is less than zero and the bridge arm state is 0, conduction loss is generated on the first anti-parallel diode D1; when the three-phase current is less than zero and the bridge arm state is 1, conduction loss is generated on the second power device T2.

[0099] The calculation of the conduction loss of the inverter in the first switching period according to the three-phase current, the first conduction time, the second conduction time, the first conduction resistance, the period of the preset carrier and the second conduction resistance includes C1-C3:

[0100] C1: performing calculation according to the three-phase current, the second conduction time, and the first conduction resistance corresponding to the second power device to obtain the conduction loss generated by the second power device.

[0101] In the embodiment of the present application, the conduction loss generated by the second power device can be calculated according to the following formula: i^2*Rdson_MOS*Ton2

[0102] In the formula, i represents the three-phase current, Rdson_MOS represents the first on-resistance corresponding to the second power device, and Ton2 represents the second on-time.

[0103] C2: Calculating according to the three-phase current, the second conduction time, the period of the preset carrier, and the second conduction resistance corresponding to the first anti-parallel diode to obtain the conduction loss generated by the first anti-parallel diode;

[0104] In the embodiment of the present application, the conduction loss generated by the first anti-parallel diode can be calculated according to the following formula: i^2*Rdson_Diode*(Ts-Ton2)

[0105] In the formula, i represents the three-phase current, Rdson_Diode represents the second on-resistance corresponding to the first anti-parallel diode, Ts represents the period of the preset carrier, and Ton2 represents the second on-time.

[0106] C3: Calculating the conduction loss of the inverter in the first switching period according to the conduction loss generated by the second power device and the conduction loss generated by the first anti-parallel diode.

[0107] In the present application, the conduction loss generated by the second power device and the conduction loss generated by the first anti-parallel diode may be added together to obtain the conduction loss of the inverter in the first switching cycle.

[0108] The present application summarizes the conduction loss as shown in Table 1, where i represents the magnitude of the three-phase current, Rdson_MOS represents the first on-resistance of the power device, dson_Diode represents the second on-resistance of the anti-parallel diode, Ton1 represents the first on-time of the upper bridge arm, and Ton2 represents the second on-time of the lower bridge arm.

[0109] i>0 i<0 The first power device T1 i^2*Rdson_MOS*Ton1 0 The second power device T2 0 i^2*Rdson_MOS*Ton2 The first anti-parallel diode D1 0 i^2*Rdson_Diode*(Ts-Ton2) The second anti-parallel diode D2 i^2*Rdson_Diode*(Ts-Ton1) 0

[0110] Table 1

[0111] By analyzing the modulation mode through the above method, the conduction loss generated by each electronic device in the switching cycle is determined, and the conduction loss can be accurately calculated, so that the loss power of the inverter can be more accurately calculated. As a possible implementation method, the switching loss includes turn-on loss, turn-off loss and reverse recovery loss, and the first corresponding relationship includes the correspondence between the three-phase current and the turn-on loss, turn-off loss and reverse recovery loss respectively. The switching loss of the inverter in the first switching cycle is calculated according to the three-phase current and the preset first corresponding relationship, including the following steps D1-D2:

[0112] D1: According to the three-phase current and the first corresponding relationship, determine the turn-on loss and turn-off loss generated by the power device, and the reverse recovery loss generated by the anti-parallel diode.

[0113] D2: Determine the switching loss based on turn-on loss, turn-off loss and reverse recovery loss.

[0114] It can be understood that the present application can obtain the data relationship between the three-phase current and the turn-on loss, turn-off loss and reverse recovery loss from the data sheet of the inverter, so as to establish a first corresponding relationship, so that after obtaining the three-phase current, the present application can determine the turn-on loss and turn-off loss, as well as the reverse recovery loss of the anti-parallel diode according to the three-phase current and the first corresponding relationship.

[0115] like Figure 4 As shown, Figure 4 A schematic diagram of a first corresponding relationship provided for the present application, wherein the horizontal axis represents the absolute value of the three-phase current, specifically the current flowing through the drain-source stage in the power device, and the vertical axis represents the turn-on loss Eon and turn-off loss Eoff of the power device under this drain-source current, as well as the reverse recovery loss Eree of the anti-parallel diode.

[0116] The present application does not limit the specific method of determining the switching loss based on the turn-on loss, turn-off loss and reverse recovery loss. As an example, the present application can add the turn-on loss, turn-off loss and reverse recovery loss to obtain the switching loss.

[0117] by Figure 2 Taking the phase arm in as an example, the present application takes the outflow bridge arm as positive, and two situations will occur according to the current being greater than zero and the current being less than zero in one switching cycle.

[0118] When the three-phase current is greater than zero, the initial state of the bridge arm is 0, and the current flows through D2. When the bridge arm state changes from 0 to 1, T1 changes from the off state to the forward conduction state, generating a turn-on loss Eon. D2 changes from the freewheeling state to the reverse cutoff state, generating a reverse recovery loss Erec; when the bridge arm state changes from 1 to 0 again, T1 changes from the forward conduction state to the off state, generating a turn-off loss Eoff. D2 changes from the reverse cutoff state to the freewheeling state. Since the forward recovery loss of the diode is extremely small, this loss can be ignored.

[0119] When the three-phase current is less than zero, the initial state of the bridge arm is 0, and the current flows through D1. When the bridge arm state changes from 0 to 1, T2 changes from the off state to the forward conduction state, generating a turn-on loss Eon. D1 changes from the freewheeling state to the reverse cutoff state, generating a reverse recovery loss Erec; when the bridge arm state changes from 1 to 0 again, T2 changes from the forward conduction state to the off state, generating a turn-off loss Eoff. D1 changes from the reverse cutoff state to the freewheeling state. The switching losses are summarized in Table 2.

[0120]

[0121] Table 2

[0122] The following is a seven-segment SVPWM modulation Figure 2 Taking the phase arm structure in the example, the process of calculating the power loss of the inverter of the present application is fully described, as follows: Figure 5 As shown, Figure 5A flow chart of another inverter power loss calculation provided by the present application. The present application will obtain the three-phase modulation wave Tcm and the three-phase current i of the first switching cycle based on the preset universal motor algorithm control model, and calculate the first conduction time Ton1 of the upper bridge arm and the second conduction time Ton2 of the lower bridge arm according to the three-phase current. The specific calculation formula is the same as above and will not be repeated here. Then, the power device and anti-parallel diode that generate switching loss and conduction loss are determined according to the positive and negative current. When the three-phase current is greater than 0, it is determined that the turn-on loss Eon and the turn-off loss Eoff are generated on the power device T1, and the reverse recovery loss Eree is generated on the anti-parallel diode D2. The present application can add the turn-on loss Eon, the turn-off loss Eoff and the reverse recovery loss Eree to obtain the switching loss of the inverter in the first switching cycle. In addition, when the three-phase current is greater than 0, it is determined that the conduction loss is generated on the power device T1, and the conduction loss is generated on the anti-parallel diode D2. The calculation formula of the conduction loss is the same as Table 1, and will not be repeated here. In the present application, the conduction loss generated on the power device T1 and the conduction loss generated on the anti-parallel diode D2 may be added to obtain the conduction loss of the inverter in the first switching cycle.

[0123] When the three-phase current is less than 0, it is determined that a turn-on loss Eon and a turn-off loss Eoff are generated on the power device T2, and a reverse recovery loss Eree is generated on the anti-parallel diode D1. The present application can add the turn-on loss Eon, the turn-off loss Eoff and the reverse recovery loss Eree to obtain the switching loss of the inverter in the first switching cycle. In addition, when the three-phase current is less than 0, it is determined that a conduction loss is generated on the power device T2, and a conduction loss is generated on the anti-parallel diode D1. The calculation formula for the conduction loss is the same as Table 1 and is not repeated here. The present application can add the conduction loss generated on the power device T2 and the conduction loss generated on the anti-parallel diode D1 to obtain the conduction loss of the inverter in the first switching cycle.

[0124] After obtaining the conduction loss and switching loss of the inverter in the first switching cycle, the two can be added together to obtain the total loss of the inverter. Then, the total loss in one switching cycle divided by the switching cycle is the loss power.

[0125] Through the above method, it is only necessary to use a general simple model to determine the three-phase modulation wave and the three-phase current, and the loss power can be calculated based on the three-phase current and the three-phase modulation wave. This method does not need to establish an accurate model of the inverter for simulation to obtain complex data, simplifies the calculation method of the loss power, and improves the efficiency of the inverter's loss power calculation.

[0126] See also Figure 6 , Figure 6A schematic diagram of the structure of a device for calculating power loss of an inverter provided in an embodiment of the present application, the device includes: an acquisition unit 601 and a calculation unit 602.

[0127] An acquisition unit 601 is used to acquire a three-phase modulation wave and a three-phase current of the inverter in a first switching cycle based on a preset universal motor algorithm control model;

[0128] A calculation unit 602, configured to calculate the switching loss of the inverter in the first switching period according to the three-phase current and a preset first corresponding relationship, wherein the first corresponding relationship includes a corresponding relationship between the three-phase current and the switching loss;

[0129] The calculation unit 602 is further configured to calculate the conduction loss of the inverter in the first switching period according to the three-phase modulation wave and the three-phase current;

[0130] The calculation unit 602 is further configured to calculate the power loss of the inverter in the first switching period according to the conduction loss and the switching loss.

[0131] Through the above-mentioned device, it is only necessary to use a general simple model to determine the three-phase modulation wave and the three-phase current, and the loss power can be calculated based on the three-phase current and the three-phase modulation wave. This method does not need to establish an accurate model of the inverter for simulation to obtain complex data, simplifies the calculation method of the loss power, and improves the efficiency of the inverter's loss power calculation.

[0132] As a possible implementation, the inverter includes a power device and an anti-parallel diode, and the acquisition unit 601 is further used to: acquire a first on-resistance of the power device, a second on-resistance of the anti-parallel diode, a period of a preset carrier, and a dead time;

[0133] The calculation unit 602 further includes:

[0134] A determination subunit, used to determine the conduction time of the bridge arm of the inverter according to the three-phase modulation wave, the period of the preset carrier and the dead time;

[0135] A calculation subunit is used to calculate the conduction loss of the inverter in the first switching period according to the conduction time, the three-phase current, the first conduction resistance and the second conduction resistance.

[0136] As a possible implementation, the on-time includes a first on-time of an upper bridge arm and a second on-time of a lower bridge arm;

[0137] A determination subunit, specifically configured to determine the first on-time according to the three-phase modulation wave and the period of a preset carrier; and determine the second on-time according to the first on-time, the period of a preset carrier and the dead time;

[0138] The calculation subunit is specifically used to calculate the conduction loss of the inverter in the first switching period according to the three-phase current, the first conduction time, the second conduction time, the first on-resistance, the period of the preset carrier and the second on-resistance.

[0139] As a possible implementation manner, the device further includes:

[0140] A determination unit is used to determine the power device that generates the switching loss and / or the conduction loss, and the anti-parallel diode that generates the switching loss and / or the conduction loss according to the positive and negative information of the three-phase current.

[0141] As a possible implementation, when the positive and negative information of the three-phase current is greater than zero, the conduction loss is generated in the first power device and the second anti-parallel diode; the conduction loss of the inverter in the first switching cycle includes: the conduction loss generated by the first power device and the conduction loss generated by the second anti-parallel diode;

[0142] The calculation subunit is specifically used to calculate according to the three-phase current, the first conduction time and the first conduction resistance corresponding to the first power device to obtain the conduction loss generated by the first power device;

[0143] Calculating according to the three-phase current, the first conduction time, the period of the preset carrier, and the second on-resistance corresponding to the second anti-parallel diode to obtain the conduction loss generated by the second anti-parallel diode;

[0144] The conduction loss of the inverter in the first switching period is calculated based on the conduction loss generated by the first power device and the conduction loss generated by the second anti-parallel diode.

[0145] As a possible implementation, when the positive and negative information of the three-phase current is less than zero, the conduction loss is generated in the second power device and the first anti-parallel diode; the conduction loss of the inverter in the first switching cycle includes: the conduction loss generated by the second power device and the conduction loss generated by the first anti-parallel diode;

[0146] The calculation subunit is specifically used to calculate according to the three-phase current, the second conduction time and the first conduction resistance corresponding to the second power device to obtain the conduction loss generated by the second power device;

[0147] Calculating according to the three-phase current, the second conduction time, the period of the preset carrier, and the second conduction resistance corresponding to the first anti-parallel diode to obtain the conduction loss generated by the first anti-parallel diode;

[0148] The conduction loss of the inverter in the first switching period is obtained by calculating according to the conduction loss generated by the second power device and the conduction loss generated by the first anti-parallel diode.

[0149] As a possible implementation, the switching loss includes turn-on loss, turn-off loss and reverse recovery loss, and the first corresponding relationship includes the corresponding relationship between the three-phase current and the turn-on loss, turn-off loss and reverse recovery loss, respectively.

[0150] Then the computing unit further includes:

[0151] The determining subunit is further used to determine the turn-on loss and turn-off loss of the power device and the reverse recovery loss of the anti-parallel diode according to the three-phase current and the first corresponding relationship;

[0152] The determining subunit is further configured to determine the switching loss according to the turn-on loss, the turn-off loss and the reverse recovery loss.

[0153] The present application also provides a power loss calculation device for an inverter, which may include a memory and a processor, wherein a computer program is stored in the memory, and when the processor calls the computer program in the memory, the steps provided in the above embodiment may be implemented. Of course, the terminal may also include various network interfaces, power supplies and other components.

[0154] It should be noted that the inverter power loss calculation device provided in the embodiment of the present application has the technical effects of any of the above embodiments, and the embodiment of the present application will not be described in detail here.

[0155] The present application also provides a computer-readable storage medium on which a computer program is stored, and when the computer program is executed, the steps provided in the above embodiment can be implemented. The storage medium may include: a USB flash drive, a mobile hard disk, a read-only memory (ROM), a random access memory (RAM), a magnetic disk or an optical disk, and other media that can store program codes.

[0156] It should be noted that a computer-readable storage medium provided in an embodiment of the present application has the technical effects of any of the above embodiments, and the embodiments of the present application are not described in detail here.

[0157] The various embodiments in this specification are described in a progressive manner, and each embodiment focuses on the differences from other embodiments. The same or similar parts between the various embodiments can be referenced to each other.

[0158] Those skilled in the art can understand that the flowchart shown in the figure is only an example in which the embodiments of the present application can be implemented, and the scope of application of the embodiments of the present application is not limited by any aspect of the flowchart.

[0159] In the several embodiments provided in the present application, it should be understood that the disclosed methods, devices and equipment can be implemented in other ways. For example, the device embodiments described above are only schematic. For example, the division of the units is only a logical function division. There may be other division methods in actual implementation, such as multiple units or components can be combined or integrated into another system, or some features can be ignored or not executed. Another point is that the mutual coupling or direct coupling or communication connection shown or discussed can be through some communication interfaces, and the indirect coupling or communication connection of the device or unit can be electrical, mechanical or other forms.

[0160] The units described as separate components may or may not be physically separated, and the components displayed as units may or may not be physical units, that is, they may be located in one place, or they may be distributed on multiple network units. Some or all of the units may be selected according to actual needs to achieve the purpose of the scheme of this embodiment. In addition, each functional unit in each embodiment of the present application may be integrated into a processing unit, or each unit may exist physically separately, or two or more units may be integrated into one unit.

[0161] If the functions are implemented in the form of software functional units and sold or used as independent products, they can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of the present application, or the part that contributes to the prior art, or the part of the technical solution, can be embodied in the form of a software product, which is stored in a storage medium and includes several instructions for enabling a computer device (which can be a personal computer, a server, or a network device, etc.) to perform all or part of the steps of the methods described in the various embodiments of the present application.

[0162] The above description of the disclosed embodiments enables those skilled in the art to implement or use the present application. Various modifications to these embodiments will be apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present application. Therefore, the present application will not be limited to the embodiments shown herein, but will conform to the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A method for calculating power loss of an inverter, characterized in that: The method comprises: Acquire the three-phase modulation wave and three-phase current of the inverter in the first switching cycle based on a preset universal motor algorithm control model; Calculating the switching loss of the inverter in the first switching period according to the three-phase current and a preset first corresponding relationship, wherein the first corresponding relationship includes a corresponding relationship between the three-phase current and the switching loss; Calculating the conduction loss of the inverter in the first switching period according to the three-phase modulation wave and the three-phase current; The power loss of the inverter in the first switching period is calculated according to the conduction loss and the switching loss.

2. The method according to claim 1, characterized in that The inverter includes a power device and an anti-parallel diode, and the method further includes: Obtaining a first on-resistance of the power device, a second on-resistance of the anti-parallel diode, a period of a preset carrier wave, and a dead time; The calculating the conduction loss of the inverter in the first switching period according to the three-phase modulation wave and the three-phase current includes: Determining the conduction time of the bridge arm of the inverter according to the three-phase modulation wave, the period of the preset carrier and the dead time; The conduction loss of the inverter in the first switching period is calculated according to the conduction time, the three-phase current, the first conduction resistance and the second conduction resistance.

3. The method according to claim 2, characterized in that The on-time includes a first on-time of an upper bridge arm and a second on-time of a lower bridge arm; Determining the conduction time of each bridge arm of the inverter according to the three-phase modulation wave, the period of the preset carrier and the dead time, including: determining the first conduction time according to the three-phase modulation wave and the period of the preset carrier; determining the second conduction time according to the first conduction time, the period of the preset carrier and the dead time; Then, calculating the conduction loss of the inverter in the first switching period according to the conduction time, the three-phase current, the first conduction resistance and the second conduction resistance includes: The conduction loss of the inverter in the first switching period is calculated according to the three-phase current, the first conduction time, the second conduction time, the first conduction resistance, the period of the preset carrier and the second conduction resistance.

4. The method according to claim 3, characterized in that The method further comprises: The power device generating the switching loss and / or the conduction loss and the anti-parallel diode generating the switching loss and / or the conduction loss are determined according to the positive and negative information of the three-phase current.

5. The method according to claim 4, characterized in that When the positive and negative information of the three-phase current is greater than zero, the conduction loss is generated in the first power device and the second anti-parallel diode; The conduction loss of the inverter in the first switching period includes: the conduction loss generated by the first power device and the conduction loss generated by the second anti-parallel diode; The calculating the conduction loss of the inverter in the first switching period according to the three-phase current, the first conduction time, the second conduction time, the first conduction resistance, the period of the preset carrier and the second conduction resistance includes: Calculating according to the three-phase current, the first conduction time, and a first conduction resistance corresponding to the first power device to obtain a conduction loss generated by the first power device; Calculating according to the three-phase current, the first conduction time, the period of the preset carrier, and the second on-resistance corresponding to the second anti-parallel diode to obtain the conduction loss generated by the second anti-parallel diode; The conduction loss of the inverter in the first switching period is calculated based on the conduction loss generated by the first power device and the conduction loss generated by the second anti-parallel diode.

6. The method according to claim 4, characterized in that When the positive and negative information of the three-phase current is less than zero, the conduction loss is generated in the second power device and the first anti-parallel diode; The conduction loss of the inverter in the first switching period includes: the conduction loss generated by the second power device and the conduction loss generated by the first anti-parallel diode; The calculating the conduction loss of the inverter in the first switching period according to the three-phase current, the first conduction time, the second conduction time, the first conduction resistance, the period of the preset carrier and the second conduction resistance includes: Calculating according to the three-phase current, the second conduction time, and the first on-resistance corresponding to the second power device to obtain a conduction loss generated by the second power device; Calculating according to the three-phase current, the second conduction time, the period of the preset carrier, and the second conduction resistance corresponding to the first anti-parallel diode to obtain the conduction loss generated by the first anti-parallel diode; The conduction loss of the inverter in the first switching period is obtained by calculating according to the conduction loss generated by the second power device and the conduction loss generated by the first anti-parallel diode.

7. The method according to claim 1, characterized in that The switching loss includes a turn-on loss, a turn-off loss and a reverse recovery loss, the first corresponding relationship includes the corresponding relationship between the three-phase current and the turn-on loss, the turn-off loss and the reverse recovery loss respectively, and the switching loss of the inverter in the first switching cycle is calculated according to the three-phase current and the preset first corresponding relationship, including: Determine, according to the three-phase current and the first corresponding relationship, a turn-on loss and a turn-off loss generated by the power device, and a reverse recovery loss generated by the anti-parallel diode; The switching loss is determined according to the turn-on loss, the turn-off loss and the reverse recovery loss.

8. A device for calculating power loss of an inverter, characterized in that: The device comprises: An acquisition unit, used for acquiring a three-phase modulation wave and a three-phase current of the inverter in a first switching cycle based on a preset universal motor algorithm control model; a calculation unit, configured to calculate the switching loss of the inverter in the first switching period according to the three-phase current and a preset first corresponding relationship, wherein the first corresponding relationship includes a corresponding relationship between the three-phase current and the switching loss; The calculation unit is further used to calculate the conduction loss of the inverter in the first switching period according to the three-phase modulation wave and the three-phase current; The calculation unit is further used to calculate the power loss of the inverter in the first switching period according to the conduction loss and the switching loss.

9. A device for calculating power loss of an inverter, characterized in that: include: Memory for storing computer programs; A processor, configured to execute the computer program stored in the memory to implement the steps of the method for calculating power loss of an inverter according to any one of claims 1 to 7.

10. A computer-readable storage medium having a computer program stored thereon, characterized in that: The computer program is executed by a processor to implement the steps of the method for calculating power loss of an inverter according to any one of claims 1 to 7.

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