Bridge inverter control method, controller and bridge inverter

Abstract

The invention provides a bridge inverter control method, the bridge inverter comprises bridge arm modules, each of the bridge arm modules comprises an upper bridge arm and a lower bridge arm, and the method comprises the following steps: judging whether all the upper bridge arms and all the lower bridge arms of the bridge arm modules can work in an active short circuit mode; and when all the upper bridge arms and all the lower bridge arms can work in the active short-circuit mode and the inverter is controlled to enter the active short-circuit mode, all the power switches of the bridge arm module are switched on to enable the inverter to work in the active short-circuit mode. A bridge inverter and an inverter system for a vehicle are also provided.

Description

Technical Field

[0001] The present application relates to inverter technology, and more specifically, to control technology of a bridge inverter. Background Art

[0002] Free Wheeling (FW) and Active Short Circuit (ASC) are two safety states of the drive motor system, which are used to prevent unexpected torque or deceleration in the drive motor and other equipment such as the vehicle using the drive motor.

[0003] Take the motor system of an electric vehicle as an example, including pure electric vehicles and hybrid electric vehicles. In an electric vehicle, a high-voltage battery drives the motor through a three-phase inverter to control the three-phase AC motor. The three-phase inverter includes three bridge arms, each of which includes an upper bridge arm and a lower bridge arm. A freewheeling diode is usually connected in parallel next to the power switch in each bridge arm to play a freewheeling role in some cases.

[0004] It is necessary to propose improvements to the control of bridge inverters. Summary of the invention

[0005] According to one aspect of the present application, a bridge inverter control method is provided, wherein the bridge inverter includes a bridge arm module, each bridge arm in the bridge arm module includes an upper bridge arm and a lower bridge arm, and the method includes: judging whether all upper bridge arms and all lower bridge arms of the bridge arm module can operate in an active short-circuit mode; when all upper bridge arms and all lower bridge arms can operate in the active short-circuit mode and the inverter is to enter the active short-circuit mode, turning on all power switches of the bridge arm module to enable the inverter to operate in the active short-circuit mode.

[0006] According to the bridge inverter control method of the example of the present application, optionally, turning on all power switches of the bridge arm module also includes disconnecting the bridge arm module from the power supply of the inverter.

[0007] According to the bridge inverter control method of the example of the present application, optionally, the method also includes: in a case where only all the lower bridge arms of the bridge arm module can operate in the active short-circuit mode, when the inverter is to enter the active short-circuit mode, controlling the power switches of all the lower bridge arms of the bridge arm module to be turned on; in a case where only the upper bridge arm of the bridge arm module can operate in the active short-circuit mode, then when the inverter is controlled to enter the active short-circuit mode, controlling the power switches of all the upper bridge arms of the bridge arm module to be turned on.

[0008] According to another aspect of the present application, a controller for a bridge inverter is also provided, the controller comprising a memory for storing instructions; a processor configured to execute the instructions and implement any one of the above methods when executing the instructions.

[0009] According to another aspect of the present application, a bridge inverter is also provided, which may include a bridge arm module and a controller. Each bridge arm in the bridge arm module may include an upper bridge arm and a lower bridge arm, and the output end of the bridge arm module may be connected to a motor. The controller is used to control all power switches of the bridge arm module to be turned on when the inverter is to enter an active short-circuit mode. For example, the controller is also used to disconnect the bridge arm module from the power supply of the inverter when all power switches of the bridge arm module are controlled to be turned on.

[0010] According to the bridge inverter of the example of the present application, optionally, the controller is also used to: in a case where only all the lower bridge arms of the bridge arm module can operate in the active short-circuit mode, when the inverter is to enter the active short-circuit mode, control the power switches of all the lower bridge arms of the bridge arm module to be turned on; in a case where only all the upper bridge arms of the bridge arm module can operate in the active short-circuit mode, when the inverter is to enter the active short-circuit mode, control the power switches of all the upper bridge arms of the bridge arm module to be turned on.

[0011] In the above examples, the bridge inverter may be a three-phase bridge inverter. In the above examples, the power switch may be an insulated gate bipolar transistor (IGBT).

[0012] An inverter system for a vehicle is also provided. The inverter system includes any one of the bridge inverters described herein, or can execute any one of the methods described herein, or includes the controller described herein.

[0013] A vehicle is also provided, the vehicle comprising any one of the bridge inverters described herein, or being capable of executing any one of the methods described herein, or comprising the controller described herein.

[0014] The high-voltage battery of an electric vehicle drives the motor through a three-phase inverter to control the three-phase AC motor. The inverter may enter the ASC mode due to the following situations: abnormal operation of the motor, abnormal high-voltage DC power supply of the inverter, failure of a switch in the inverter circuit, etc. In the ASC mode, all the upper bridge arm power switches in each bridge arm of the three-phase bridge inverter are disconnected, and all the lower bridge arm switches are turned on, and the back electromotive force of the motor is consumed in the internal winding of the motor. However, in the ASC mode, the power switch of the lower bridge arm is always turned on and the power switch of the upper bridge arm is always turned off, so that the ASC large current is always applied to the power switch and the motor of the lower bridge arm, and the power switch of the lower bridge arm continues to heat up. The temperature rise may exceed the temperature that the power switch can withstand, causing damage to the power switch. Executing the bridge inverter control method according to the example of this application or using the controller and bridge inverter according to the example of this application can effectively avoid the occurrence of this situation. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] The following will describe the embodiments of the present application in detail with reference to the accompanying drawings so that the present application can be more fully understood, wherein:

[0016] Figure 1 is a flow chart of a bridge inverter control method according to an example of the present application;

[0017] Figure 2 is a schematic structural diagram of a bridge inverter according to an example of the present application;

[0018] Figure 3 is a flow chart of a bridge inverter control method according to some examples of the present application;

[0019] Figure 4 It is a schematic diagram of the structure of a controller according to an example of the present application. DETAILED DESCRIPTION

[0020] In order to make the purpose, technical scheme and advantages of the embodiments of the present application clearer, the following will be combined with the accompanying drawings to clearly and completely describe the implementation methods of the present application. It should be noted that the described implementation methods are only partial implementation methods of the technical scheme of the present application, not all. All other implementation methods obtained by ordinary technicians in this field based on the implementation methods recorded in the application documents without paying creative work are covered by the protection scope of the present application.

[0021] The terms "first", "second", etc. in the specification, claims and drawings of this application are used to distinguish similar objects, rather than to describe a specific order or sequence. In addition, "first" and "second" are used for descriptive purposes only and should not be understood as explicitly or implicitly indicating relative importance or implicitly indicating the number of technical features indicated. Therefore, the features defined as "first" and "second" may explicitly or implicitly include one or more of the features. In the description of the embodiments of this application, unless otherwise specified, "multiple" means two or more.

[0022] As used hereinafter, the words “example” or “exemplarily” or “exemplarily” mean “serving as an example, embodiment, or illustration.” Any embodiment described as “example” or “exemplarily” or “exemplarily” is not necessarily to be construed as preferred or advantageous over other embodiments.

[0023] Figure 1 1 is a flow chart of a bridge inverter control method according to an example of the present application. The bridge inverter implementing the method may include a bridge arm module, each of which includes an upper bridge arm and a lower bridge arm. In the example of the present application, the bridge arm module may include three bridge arms. In some application scenarios, the output end of the bridge arm module is connected to the motor.

[0024] like Figure 1 As shown, in step S100, it is determined whether the three upper bridge arms and the three lower bridge arms of the bridge arm module of the inverter can all work in the active short circuit (ASC) mode. During the operation of the inverter and the motor, the inverter may enter the ASC mode in multiple cases. For example, the motor is operating abnormally; the high-voltage power supply of the inverter is abnormal, including the high-voltage power supply voltage is too high; a switch failure occurs in the inverter circuit. Once the inverter or the motor has a situation that causes the inverter to enter the ASC mode, the inverter will be controlled to enter the ASC mode. According to the example of the present application, before the inverter is controlled to enter the ASC mode, that is, when entering the ASC mode, it is first determined whether the three upper bridge arms and the three lower bridge arms of the inverter can all work in the ASC mode, and the controller of the inverter can perform this step. Specifically, the controller of the inverter determines the working state of the power switch according to the signal sent by the power switch of each bridge arm, thereby determining whether the bridge arm can work in the ASC mode.

[0025] In step S102, when the three upper bridge arms and the three lower bridge arms can all work in the ASC mode and the inverter is to enter the ASC mode, each power switch in the three bridge arms of the bridge arm module is turned on. According to an example of the present application, while all the power switches in the three bridge arms of the bridge arm module are turned on, the bridge arm module is disconnected from the power supply of the inverter. In a specific embodiment, the time of disconnecting the bridge arm module from the power supply of the inverter may be slightly earlier than the time of turning on all the power switches in the three bridge arms.

[0026] In this way, in ASC mode, the bridge arm module is disconnected from the power supply of the inverter, preventing the power supply from being damaged when the power switches of the three bridge arms are directly turned on. On the other hand, the windings of the motor connected to the inverter (such as the stator winding) form a loop with the power switches of the upper bridge arm and the lower bridge arm of the bridge arm module respectively, and the back electromotive force energy generated by the motor is released through the loop. Since the current generated by the back electromotive force energy is shunted by the upper and lower bridge arms, the current flowing through each power switch is reduced by half compared to when only the upper bridge arm or the lower bridge arm is turned on, which greatly reduces the probability of power switch damage.

[0027] Figure 2 3 is a schematic diagram of the structure of a bridge inverter according to an example of the present application. The output end of the bridge inverter 32 is connected to the motor 4. The power supply 30 of the inverter is connected to the inverter 32 via a switch device 31. The inverter can be applied to an electric vehicle, such as a pure electric vehicle or a hybrid electric vehicle.

[0028] According to the example of the present application, the bridge inverter 32 may include a bridge arm module and a controller 34. In this example, the bridge arm module may include a first bridge arm 11, a second bridge arm 12 and a third bridge arm 13. The first bridge arm 11, the second bridge arm 12 and the third bridge arm 13 include an upper bridge arm and a lower bridge arm, respectively. Each bridge arm includes an upper bridge arm and a lower bridge arm, and each upper bridge arm and each lower bridge arm include a power switch. In the example of the present application, the power switch is an insulated gate bipolar transistor (IGBT), but the power switch may also be a power transistor (GTR), a gate turn-off thyristor (GTO), a power field effect transistor (PowerMOSFET), an integrated gate commutated thyristor (IGCT), etc. By way of example and not limitation, the three bridge arms 11, 12 and 13 of the bridge arm module can be turned on and off in a certain order under the action system of the controller 34 to output an electrical signal. In the example of the present application, the three bridge arms 11, 12 and 13 output three-phase electrical signals with equal amplitude, equal frequency and 120° phase difference, which are transmitted to the motor 4 connected to the output ends of the three bridge arms. In other words, the bridge inverter in this example is a three-phase bridge inverter. However, the bridge inverter can also be set as a two-phase bridge inverter.

[0029] In this example with IGBT as the power switch, the upper bridge arm of the first bridge arm 11 includes IGBT Sa1 and IGBT Sa2, and the lower bridge arm includes IGBT Sa3 and IGBT Sa4; the upper bridge arm of the second bridge arm 12 includes IGBT Sb1 and IGBT Sb2, and the lower bridge arm includes IGBT Sb3 and IGBT Sb4; the upper bridge arm of the third bridge arm 13 includes IGBT Sc1 and IGBT Sc2, and the lower bridge arm includes IGBT Sc3 and IGBT Sc4. The upper bridge arm and the lower bridge arm of each bridge arm are respectively connected to the power supply 30. In this example, the upper bridge arm is connected to the positive pole of the power supply 30 and the lower bridge arm is connected to the negative pole of the power supply 30. The output ends of the first bridge arm 11, the second bridge arm 12 and the third bridge arm 13 are the connection points of the upper bridge arm and the lower bridge arm of each bridge arm. The switch device 31 is exemplarily a relay, which is arranged on the DC busbar that transmits DC power from the high-voltage power supply 30 to the three-phase inverter 32, and is used to connect or disconnect the electrical connection between the high-voltage power supply 30 and the bridge arm module. When the inverter is about to enter the active short-circuit mode, the controller 34 determines whether all bridge arms of the bridge arm module can work in the active short-circuit mode, and when all bridge arms can work in the active short-circuit mode, controls the switch device 31 to disconnect the electrical connection between the power supply 30 and the bridge arm module and controls all power switches of the bridge arm module to be turned on.

[0030] Figure 3 is a flow chart of a bridge inverter control method according to some examples of the present application, which can be Figure 2 The bridge inverter 32 is shown to be implemented.

[0031] Please also refer to Figure 3 and Figure 2 . In step S300, the controller 34 determines whether the three upper bridge arms and the three lower bridge arms can all operate in the ASC mode. According to the example of the present application, when the controller 34 receives the trigger signal for the three-phase inverter 32 to enter the ASC mode, it can judge the state of each IGBT according to the signal transmitted to it by the driver chip of each IGBT (Sa1, Sa2, Sa3, Sa4, Sb1, Sb2, Sb3, Sb4, Sc1, Sc2, Sc3 and Sc4), so as to determine whether each upper bridge arm and lower bridge arm of the bridge arm module can all operate in the ASC mode, that is, whether each IGBT can make the collector and the emitter conduct to operate. It should be noted that the drive chip mentioned here can be a drive control circuit. Considering that when the inverter system is arranged in a device such as a vehicle that uses an inverter, the drive control circuit of each IGBT can be implemented in the chip, so the drive control circuit of the IGBT is also referred to as a drive chip here.

[0032] When the controller 34 determines in step S300 that the three upper bridge arms and the three lower bridge arms are all operable in the ASC mode, the controller 34 controls the relay 31 to disconnect so that the first bridge arm 11, the second bridge arm 12 and the third bridge arm 13 of the bridge arm module are disconnected from the power supply 30; at the same time, the controller 34 controls each IGBT (Sa1, Sa2, Sa3, Sa4, Sb1, Sb2, Sb3, Sb4, Sc1, Sc2, Sc3 and Sc4) to enter the collector-to-emitter conduction state, as shown in step S302-1. For example, the controller 34 sends a signal to the driver chip of each IGBT to make the IGBT conduct directly. Figure 2 The arrows in the figure indicate the current flow in the ASC mode when the IGBT collector to emitter of each bridge arm of the inverter is turned on. Figure 2 As shown, the current I generated by the electric energy of the motor 4 flows into the upper bridge arm of the first bridge arm 11 and the lower bridge arm of the first bridge arm 11 through the a-phase line. Specifically, the current flowing into the IGBT Sa2 and Sa1 of the upper bridge arm of the first bridge arm 11 is the current I a-above The current flowing into the IGBT Sa3 and Sa4 of the lower bridge arm of the first bridge arm 11 is the current I a-below Current I a-above After passing through the upper bridge arm of the first bridge arm, the current flows into the upper bridge arm of the second bridge arm 12 and the upper bridge arm of the third bridge arm 13 respectively. a-below After passing through the lower bridge arm of the first bridge arm, the current flows into the lower bridge arm of the second bridge arm 12 and the lower bridge arm of the third bridge arm 13. As a result, the current I generated by the motor 4 is shared by the upper bridge arm and the lower bridge arm, that is, the current I is divided into the current I a-above and current I a-below It should be noted that the current flow direction of the motor 4 is not limited to flowing into the first bridge arm 11 through the a-phase line and returning to the motor 4 through the second and third bridge arms 12 and 13 as shown here. In other examples, the current I of the motor 4 may flow into the second bridge arm 12 through the b-phase line and return to the motor through the first bridge arm 11 and the third bridge arm 13; or, the current I of the motor 4 may flow into the third bridge arm 13 through the c-phase line and return to the motor 4 through the first bridge arm 11 and the second bridge arm 12.

[0033] When the judgment result of step S300 is that only three lower bridge arms can enter the active short-circuit mode, the controller 34 controls the IGBTs of the three lower bridge arms of the inverter 32 to be directly turned on. In this case, the IGBTs of the three upper bridge arms are in the off state, as shown in step S302-2. For example, the current I generated by the back electromotive force of the motor 4 flows into the IGBTs Sa3 and Sa4 of the lower bridge arm of the first bridge arm through the a-phase line, and then flows into the lower bridge arm of the second bridge arm 12 and the lower bridge arm of the third bridge arm 13, that is, returns to the motor and the IGBTs Sc4 and Sc3 of the lower bridge arm of the third bridge arm 13 through IGBTSb4 and Sb3, respectively, and returns to the motor 4.

[0034] When the result of the judgment in step S300 is that only three upper bridge arms can enter the active short-circuit mode, the controller 34 controls the IGBTs of the three upper bridge arms of the inverter 32 to be directly turned on. In this case, the IGBTs of the three lower bridge arms are in the off state, as shown in step S302-3. For example, the current I generated by the back electromotive force of the motor 4 flows into the IGBTs Sa2 and Sa1 of the upper bridge arm of the first bridge arm through the a-phase line, and then flows into the upper bridge arm of the second bridge arm 12 and the upper bridge arm of the third bridge arm 13, that is, returns to the motor through IGBTs Sb1 and Sb2 and returns to the motor 4 through IGBTs Sc1 and Sc2 of the lower bridge arm of the third bridge arm 13.

[0035] When the result of the determination in step S300 is that none of the three upper bridge arms and the three lower bridge arms can operate in the active short-circuit mode, the controller 34 controls the bridge inverter 32 to enter the coasting mode, as shown in step S302 - 4 .

[0036] As an example, when any one of the three upper bridge arm IGBTs is abnormal and the three lower bridge arm IGBTs can be directly turned on, the three lower bridge arms are controlled to work in the ASC mode; vice versa. When the three upper bridge arm IGBTs and the three lower bridge arm IGBTs all include an abnormal IGBT that cannot enter the ASC mode, the inverter 32 is controlled to enter the coasting mode.

[0037] According to the examples of the present application, when the inverter is controlled to enter the ASC mode, all power switches can be controlled to be turned on when each power switch of the bridge arm module can be turned on, thereby entering the ASC mode, so that the current flowing into the inverter by the motor is shared by the upper bridge arm and the lower bridge arm. Therefore, compared with entering the ASC mode only through the upper bridge arm or only through the lower bridge arm, all bridge arms work in the ASC mode, so that the current flowing through each power switch is greatly reduced, avoiding the problem of excessive junction temperature caused by the instantaneous increase of current on the power switch. Further, according to the examples of the application, when all power switches cannot be turned on, it will be selected to control only the upper bridge arm or the lower bridge arm to enter the ASC mode. In general, compared with the conventional method of only being able to control the upper bridge arm or only being able to control the lower bridge arm to enter the ASC mode, according to the present application, the control of the bridge inverter is more flexible.

[0038] According to the actual test data of the inventor of the present application, a motor system using the three-phase bridge inverter according to the present application is compared with a motor system not using the three-phase bridge inverter according to the example of the present application: in the ASC mode with the IGBT of each bridge arm directly turned on (collector to emitter conduction), under the condition of a cooling water temperature of 65 degrees Celsius, the IGBT junction temperature rises to about 43.4 degrees Celsius, which is lower than 46 degrees Celsius when the method or inverter according to the example of the present application is not adopted; and the maximum current of the three-phase current flowing through the IGBT is approximately 43A, which is lower than 85A when the method or inverter according to the example of the present application is not adopted.

[0039] According to an example of the present application, a controller is further provided for controlling the bridge inverter. Figure 4 The structure diagram of the controller is shown in FIG. Figure 4 As shown, the controller includes a memory 40 and a processor 42. The memory 40 stores instructions, and the processor 42 executes the instructions. When the processor 42 executes the instructions, the various examples of the bridge inverter control method described above can be implemented. For example, the controller can be implemented as described above in combination with Figure 2 The controller 34 described herein may be implemented in the controller 34 .

[0040] The present application also provides a vehicle, which can include an inverter 32 according to an example of the present application or an inverter system ( Figure 2 As shown), or any embodiment of the inverter control method according to the example of the present application may be executed.

[0041] Although various embodiments of the present application have been shown and described in detail to illustrate the principles of the present application, it should be understood that the various embodiments and their features can be combined with each other without conflict to achieve new implementations, and such implementations should be included in the scope claimed by the present application. In addition, the present application can also be implemented in other ways that do not deviate from the spirit of the present application.

Claims

1. A control method for a bridge inverter, wherein the bridge inverter comprises a bridge arm module, each bridge arm in the bridge arm module comprises an upper bridge arm and a lower bridge arm, characterized in that: The method comprises: Determine whether all upper bridge arms and all lower bridge arms of the bridge arm module can operate in an active short-circuit mode; When all upper bridge arms and all lower bridge arms can operate in the active short-circuit mode and the inverter is about to enter the active short-circuit mode, all power switches of the bridge arm modules are turned on.

2. The method according to claim 1, characterized in that The step of turning on all power switches of the bridge arm module further includes: disconnecting the bridge arm module from a power source of the inverter.

3. The method according to claim 1, characterized in that The method further comprises: In the case that only all lower bridge arms of the bridge arm module can operate in the active short-circuit mode, when the inverter is to enter the active short-circuit mode, controlling the power switches of all lower bridge arms of the bridge arm module to be turned on; In the case that only the upper bridge arm of the bridge arm module can operate in the active short-circuit mode, when the inverter is controlled to enter the active short-circuit mode, the power switches of all the upper bridge arms of the bridge arm module are controlled to be turned on.

4. The method according to claim 1, characterized in that: The bridge inverter is a three-phase bridge inverter.

5. The method according to any one of claims 1 to 4, characterized in that The power switch is an IGBT.

6. A controller for a bridge inverter, the controller comprising: A memory for storing instructions; as well as A processor, configured to execute the instructions, and implement the method according to any one of claims 1 to 3 when executing the instructions.

7. A bridge inverter, characterized in that: include: A bridge arm module, each bridge arm in the bridge arm module comprises an upper bridge arm and a lower bridge arm; The controller is used to control all power switches of the bridge arm modules to be turned on when it is determined that all bridge arms of the bridge arm modules can operate in the active short-circuit mode and when the inverter is about to enter the active short-circuit mode.

8. The bridge inverter according to claim 7, characterized in that: The controller is also used to disconnect the bridge arm module from the power supply of the inverter when controlling all power switches of the bridge arm module to be turned on.

9. The bridge inverter according to claim 7, characterized in that: The controller is also used for: In the case that only all lower bridge arms of the bridge arm module can operate in the active short-circuit mode, when the inverter is to enter the active short-circuit mode, controlling the power switches of all lower bridge arms of the bridge arm module to be turned on; In the case that only all upper bridge arms of the bridge arm module can operate in the active short-circuit mode, when the inverter is to enter the active short-circuit mode, the power switches of all upper bridge arms of the bridge arm module are controlled to be turned on.

10. The bridge inverter according to claim 7, characterized in that: The bridge inverter is a three-phase bridge inverter.

11. The bridge inverter according to any one of claims 7 to 9, characterized in that: The power switch is an IGBT.

12. An inverter system for a vehicle, characterized in that: The inverter system includes the bridge inverter according to any one of claims 7 to 11, or can execute the method according to any one of claims 1 to 5, or includes the controller according to claim 6.

13. A vehicle, characterized in that: The vehicle comprises the bridge inverter according to any one of claims 7 to 11, or is capable of executing the method according to any one of claims 1 to 5, or comprises the controller according to claim 6.

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