Bootstrap circuit charging method, controller and power utilization system

Abstract

The invention discloses a charging method of a bootstrap circuit, a controller and a power utilization system. The bootstrap circuit comprises an energy storage element, and the method comprises the following steps of: performing at least one charging operation on the energy storage element by taking a preset charging unit duration as a period; after the execution of each charging operation is completed, calculating the effective charging duration of the energy storage element and detecting the current of the load side; after the Nth charging operation is executed, according to the comparison result of the current of the load side and the preset rated current, the (N + 1) th charging operation is executed on the energy storage element or the (N + 1) th charging operation is executed after the discharging operation is executed on the energy storage element, and N is an integer larger than or equal to 1; and under the condition that the charging effective duration reaches the target charging total duration, charging is ended. According to the embodiment of the invention, the problem of short-circuit current when the load motor is started can be effectively avoided, and reliable starting and operation of the motor are ensured.

Description

Technical Field

[0001] The present application belongs to the field of power electronics technology, and in particular relates to a charging method, a controller and a power consumption system of a bootstrap circuit. Background Art

[0002] In low-power motor controllers, in order to reduce costs, a bootstrap circuit is often used to power the drive circuit of the upper bridge power transistor.

[0003] When using the bootstrap circuit, the power transistor of the lower bridge must be turned on first to charge the energy storage element to a certain value before the power transistor of the upper bridge can be turned on. Before the motor starts, if the power transistors of the three-phase lower bridge are turned on at the same time, the three-phase windings of the motor will be short-circuited. At this time, if the motor speed is high, a large short-circuit current will be generated, which may trigger the overcurrent fault protection of the motor controller, and even cause demagnetization of the motor or breakdown damage of the power transistor. Summary of the invention

[0004] The embodiments of the present application provide a charging method, a controller and a power consumption system for a bootstrap circuit, which can effectively avoid the short-circuit current problem when the load motor is started and ensure the reliable starting and operation of the motor.

[0005] In a first aspect, an embodiment of the present application provides a charging method of a bootstrap circuit, wherein the bootstrap circuit includes an energy storage element, and the method includes:

[0006] Perform at least one charging operation on the energy storage element with a preset charging unit time as a period;

[0007] After each charging operation is completed, the effective charging time of the energy storage element is calculated and the current on the load side is detected;

[0008] After the Nth charging operation is completed, according to the comparison result between the current on the load side and the preset rated current, the energy storage element is charged for the N+1th time or the discharge operation is performed and then the N+1th charging operation is performed, where N is an integer greater than or equal to 1;

[0009] When the effective charging time reaches the target total charging time, the charging is terminated.

[0010] In a possible embodiment of the first aspect, the charging operation includes controlling a switch tube of an upper bridge arm in the bootstrap circuit to be disconnected, and controlling a switch tube of a lower bridge arm in the bootstrap circuit to be turned on;

[0011] And / or, the discharging operation includes controlling the switch tube of the upper bridge arm and the switch tube of the lower bridge arm in the bootstrap circuit to be disconnected.

[0012] In a possible embodiment of the first aspect, after the Nth charging operation is completed, according to a comparison result between the current on the load side and the preset rated current, performing an N+1th charging operation on the energy storage element or performing a discharging operation and then performing an N+1th charging operation, including:

[0013] When the current on the load side is greater than the preset rated current after the Nth charging operation is completed, a discharge operation is performed on the energy storage element according to a preset discharge unit time; after the discharge operation is completed, an N+1th charging operation is performed on the energy storage element; or,

[0014] When the current on the load side is less than or equal to the preset rated current after the Nth charging operation is completed, the N+1th charging operation is performed on the energy storage element.

[0015] In a possible embodiment of the first aspect, performing at least one charging operation on the energy storage element with a preset charging unit time as a period includes:

[0016] In response to a load start instruction, start interrupt service;

[0017] Perform at least one charging operation on the energy storage element with a preset charging unit time as a period;

[0018] When the effective charging time reaches the target total charging time, the charging is terminated, including:

[0019] When the effective charging time reaches the target total charging time, the interruption service is exited and the load is started.

[0020] In a possible embodiment of the first aspect, the effective charging time of the energy storage element is the difference between the cumulative charging time and the cumulative discharging time, wherein the cumulative charging time is the product of the number of executions of the charging operation and the preset charging unit time, and the cumulative discharging time is the product of the number of executions of the discharging operation and the preset discharging unit time.

[0021] In a possible embodiment of the first aspect, the preset charging unit time length is M times the preset discharging unit time length, where M is a real number greater than 1.

[0022] In a possible embodiment of the first aspect, a counter is used to calculate the effective charging time of the energy storage element;

[0023] Te=Cnt×Tc

[0024] Among them, Te is the effective charging time, Cnt is the value of the counter, Tc is the preset discharge unit time, the initial value of the counter is 0, the value of the counter is increased by M each time a charging operation is performed, and the value of the counter is decreased by 1 each time a discharging operation is performed.

[0025] In a possible embodiment of the first aspect, when the effective charging time reaches the target total charging time, before ending the charging, the method further includes:

[0026] Charging at least one energy storage element of the same type after it is discharged, and obtaining at least one piece of information on the time it takes to fully charge the energy;

[0027] In at least one piece of information on full charge time, determine the longest full charge time as the total charging time;

[0028] Multiply the total charging time by the preset coefficient to get the target total charging time.

[0029] Based on the same inventive concept, in the second aspect, an embodiment of the present application further provides a controller, comprising: a processor and a memory storing computer program instructions; when the processor executes the computer program instructions, the charging method of the bootstrap circuit as described in any embodiment of the first aspect is implemented.

[0030] Based on the same inventive concept, in a third aspect, an embodiment of the present application further provides a power consumption system, the system comprising: a bootstrap circuit, a load, and a controller as described in the second aspect.

[0031] The charging method, controller and power system of the bootstrap circuit of the embodiment of the present application, wherein the bootstrap circuit includes an energy storage element, and the charging method of the bootstrap circuit performs at least one charging operation on the energy storage element with a preset charging unit duration as a period, and each charging operation is performed for a preset charging unit duration, so that periodic charging can be performed. Wherein, after each charging operation is completed, the effective charging time of the energy storage element is calculated and the current on the load side is detected, and after each (Nth) charging operation is completed, according to the comparison result of the current on the load side with the preset rated current, the energy storage element is subjected to the next (N+1th) charging operation or the next (N+1th) charging operation is performed after the discharge operation, so that the charging strategy can be adjusted according to the load current. Then, when the effective charging time reaches the target total charging time, the charging is terminated. The charging method of the bootstrap circuit is to charge periodically, calculate the effective charging time and detect the load current after each charge, and flexibly decide whether to charge directly for the next time or discharge first and then charge according to the comparison result of the load current and the rated value, so as to adjust the charging strategy according to the load current until the effective charging time reaches the target charging time. This periodic charging and intelligent adjustment of charging and discharging strategy effectively avoids the short-circuit current problem when the load motor starts, and ensures the reliable starting and operation of the motor. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] Other features, objects and advantages of the present application will become more apparent by reading the following detailed description of non-limiting embodiments with reference to the accompanying drawings, in which the same or similar reference numerals represent the same or similar features and the accompanying drawings are not drawn to scale.

[0033] Figure 1 It is a flow chart of a charging method of a bootstrap circuit provided in an embodiment of the present application;

[0034] Figure 2 It is a flow chart of a charging method of a bootstrap circuit provided in an embodiment of the present application;

[0035] Figure 3 It is a flow chart of a charging method of a bootstrap circuit provided in an embodiment of the present application;

[0036] Figure 4 It is a flow chart of a charging method of a bootstrap circuit provided in an embodiment of the present application;

[0037] Figure 5 It is a flow chart of a charging method of a bootstrap circuit provided in an embodiment of the present application;

[0038] Figure 6 is a circuit structure diagram of a controller provided in an embodiment of the present application;

[0039] Figure 7 This is a schematic diagram of a circuit structure of an electric power system provided in an embodiment of the present application;

[0040] Figure 8 It is a schematic diagram of the circuit structure of a bootstrap circuit driving a single-phase upper and lower bridge arm switch tube in a power system provided by an embodiment of the present application;

[0041] Fig. 9 This is another structural schematic diagram of the power consumption system provided in the embodiment of the present application. DETAILED DESCRIPTION

[0042] The features and exemplary embodiments of various aspects of the present application will be described in detail below. In order to make the purpose, technical solutions and advantages of the present application clearer, the present application will be further described in detail below in conjunction with the accompanying drawings and specific embodiments. It should be understood that the specific embodiments described herein are only configured to explain the present application and are not configured to limit the present application. For those skilled in the art, the present application can be implemented without the need for some of these specific details. The following description of the embodiments is only to provide a better understanding of the present application by illustrating the examples of the present application.

[0043] It should be noted that, in this article, relational terms such as first and second, etc. are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Moreover, the terms "include", "comprise" or any other variants thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or device. In the absence of further restrictions, the elements defined by the statement "include..." do not exclude the presence of other identical elements in the process, method, article or device including the elements.

[0044] It should be understood that the term "and / or" used in this article is only a description of the association relationship of associated objects, indicating that there can be three relationships. For example, A and / or B can represent: A exists alone, A and B exist at the same time, and B exists alone. In addition, the character " / " in this article generally indicates that the associated objects before and after are in an "or" relationship.

[0045] It is obvious to those skilled in the art that various modifications and changes can be made in the present application without departing from the spirit or scope of the present application. Therefore, the present application is intended to cover modifications and changes of the present application that fall within the scope of the corresponding claims (technical solutions for protection) and their equivalents. It should be noted that the implementation methods provided in the embodiments of the present application can be combined with each other without contradiction.

[0046] Before describing the technical solutions provided by the embodiments of the present application, in order to facilitate the understanding of the embodiments of the present application, the present application first specifically describes the problems existing in the related art:

[0047] In low-power motor controllers, in order to reduce costs, a bootstrap circuit is often used to power the drive circuit of the upper bridge power transistor.

[0048] The bootstrap circuit is a special circuit configuration that stores charges through energy storage elements (such as capacitors) in the circuit, and then releases these charges to increase or adjust the voltage level in the circuit. It can be used in situations where high voltage output is required, such as driving LEDs, LCD backlights, motor control, etc.

[0049] When using the bootstrap circuit, the power transistor of the lower bridge must be turned on first to charge the energy storage element to a certain value before the power transistor of the upper bridge can be turned on. Before the motor starts, if the power transistors of the three-phase lower bridge are turned on at the same time, the three-phase windings of the motor will be short-circuited. At this time, if the motor speed is high, a large short-circuit current will be generated, which may trigger the overcurrent fault protection of the motor controller, and even cause demagnetization of the motor or breakdown damage of the power transistor.

[0050] For example, when using the bootstrap circuit to power the upper bridge IGBT driver, the lower bridge IGBT must be turned on first, and the energy storage element (such as a capacitor) must be charged to a certain value (such as 15V) before the bootstrap circuit can power the upper bridge IGBT driver and the upper bridge IGBT can be controlled to turn on. Before the motor starts, if the three-phase lower bridge IGBT is controlled to be turned on at the same time, the three-phase winding of the motor is in a short-circuit state. At this time, if the motor speed is high, a large short-circuit current will be generated on the three phases of the motor, which may cause the motor controller to trigger the overcurrent fault protection, and even cause the motor to demagnetize or the IGBT to break down.

[0051] Based on this, the embodiments of the present application provide a charging method, a controller and a power consumption system for a bootstrap circuit, which can effectively avoid the short-circuit current problem when the load motor is started and ensure the reliable starting and operation of the motor.

[0052] The charging method of the bootstrap circuit provided in the embodiment of the present application is described in detail below with reference to the accompanying drawings.

[0053] Figure 1 is a schematic flow chart of a charging method for a bootstrap circuit provided in an embodiment of the present application, such as Figure 1 As shown, the bootstrap circuit includes an energy storage element, and the charging method of the bootstrap circuit may include steps S110 to S140.

[0054] S110, performing at least one charging operation on the energy storage element with a preset charging unit time period as a period.

[0055] Among them, the preset charging unit time is a single charging time for charging the energy storage element, which can be set according to demand, and the embodiment of the present application does not limit this.

[0056] An energy storage element is an element that can store energy. The energy storage element can release the stored energy when needed to supply power to a load. For example, the energy storage element can be a capacitor.

[0057] Specifically, when charging the energy storage element, at least one charging may be performed, and each charging duration is a preset charging unit duration.

[0058] S120, after each charging operation is completed, the effective charging time of the energy storage element is calculated and the current on the load side is detected.

[0059] Specifically, two main tasks can be performed after each charging operation: one is to calculate the effective charging time of the energy storage element; the other is to detect the current flowing through the load side connected to the energy storage element to evaluate the charging condition of the energy storage element and the working status of the load.

[0060] S130, after the Nth charging operation is completed, according to the comparison result of the current on the load side with the preset rated current, the energy storage element is charged for the N+1th time or the discharge operation is performed and then the N+1th charging operation is performed, where N is an integer greater than or equal to 1.

[0061] The current on the load side is the actual current of the load. The preset rated current is the maximum operating current of the load. The load is an electrical device, such as a motor.

[0062] Specifically, after completing a charging operation, the next operation can be determined based on the comparison result between the load side current and the rated current of the load. For example, if the load side current is less than or equal to the rated current of the load, the next charging operation is performed directly; if the load side current is greater than the rated current of the load, a discharge operation is performed first to adjust the state of the energy storage element, and then the next charging operation is performed.

[0063] S140: When the effective charging time reaches the target total charging time, the charging is terminated.

[0064] Specifically, when the effective charging time of the energy storage element reaches a preset target total charging time, the current charging operation will be stopped, marking the end of the charging process.

[0065] According to the charging method of the bootstrap circuit provided in the embodiment of the present application, the bootstrap circuit includes an energy storage element, and the charging method of the bootstrap circuit performs at least one charging operation on the energy storage element with a preset charging unit duration as a period, and each charging operation lasts for a preset charging unit duration, so that periodic charging can be performed. Wherein, after each charging operation is completed, the effective charging time of the energy storage element is calculated and the current on the load side is detected, and after each (Nth) charging operation is completed, the next (N+1th) charging operation is performed on the energy storage element according to the comparison result of the current on the load side with the preset rated current, or the next (N+1th) charging operation is performed after the discharge operation is performed, so that the charging strategy can be adjusted according to the load current. Then, when the effective charging time reaches the target total charging time, the charging is terminated. The charging method of the bootstrap circuit is to charge periodically, calculate the effective charging time and detect the load current after each charge, and flexibly decide whether to charge directly for the next time or discharge first and then charge according to the comparison result of the load current and the rated value, so as to adjust the charging strategy according to the load current until the effective charging time reaches the target charging time. This periodic charging and intelligent adjustment of charging and discharging strategy effectively avoids the short-circuit current problem when the load motor starts, and ensures the reliable starting and operation of the motor.

[0066] In some embodiments, the charging operation includes controlling the switch tube of the upper bridge arm in the bootstrap circuit to be turned off, and controlling the switch tube of the lower bridge arm in the bootstrap circuit to be turned on.

[0067] Specifically, the energy storage element can be charged by controlling the switch tube of the upper bridge arm in the bootstrap circuit to be disconnected and controlling the switch tube of the lower bridge arm in the bootstrap circuit to be turned on.

[0068] And / or, the discharging operation includes controlling the switch tube of the upper bridge arm and the switch tube of the lower bridge arm in the bootstrap circuit to be disconnected.

[0069] Specifically, the energy storage element can be discharged by controlling the switch tube of the upper bridge arm and the switch tube of the lower bridge arm in the bootstrap circuit to be turned off.

[0070] The embodiment of the present application can realize charging and discharging operations of the energy storage element by accurately controlling the disconnection and conduction states of the upper bridge arm and the lower bridge arm switch tubes in the bootstrap circuit.

[0071] Figure 2 This is another flow chart of the charging method of the bootstrap circuit provided in the embodiment of the present application.

[0072] In some embodiments, Figure 2As shown, after the Nth charging operation is completed, step S130 performs the N+1th charging operation on the energy storage element or performs the discharge operation and then the N+1th charging operation according to the comparison result of the current on the load side and the preset rated current, which may include steps S131 and S132.

[0073] S131, when the current on the load side is greater than the preset rated current after the Nth charging operation is completed, a discharge operation is performed on the energy storage element according to a preset discharge unit time; after the discharge operation is completed, an N+1th charging operation is performed on the energy storage element.

[0074] Specifically, after each charging operation, it can be determined whether the energy storage element needs to be discharged or charged based on the comparison result between the load-side current and the rated current of the load. Specifically, if the load-side current exceeds the rated current of the load after the charging operation, the energy storage element will be discharged once according to the preset discharge unit time, and the next charging operation will be performed after the discharge operation is completed.

[0075] Alternatively, S132, when the current on the load side is less than or equal to the preset rated current after the Nth charging operation is completed, performing the N+1th charging operation on the energy storage element.

[0076] Specifically, if the load-side current does not exceed the rated current of the load after the charging operation, the energy storage element can be directly charged for the next time without performing an additional discharge process.

[0077] The charging method of the bootstrap circuit provided in the embodiment of the present application includes determining the subsequent operation after the Nth charging operation according to whether the load side current exceeds the preset rated current: if it exceeds, the energy storage element is first discharged once according to the preset discharge unit time, and then the N+1th charging operation is performed; if it does not exceed, the energy storage element is directly charged for the N+1th time without additional discharge, thereby realizing intelligent charging management of the energy storage element. According to the comparison result between the load current and the rated value, it can be flexibly determined whether to directly perform the next charge or discharge first and then charge, so that the charging strategy can be adjusted according to the load current until the effective charging time reaches the target charging time. This periodic charging and intelligent adjustment of the charging and discharging strategy effectively avoids the short-circuit current problem when the load motor starts, and ensures the reliable starting and operation of the motor.

[0078] Figure 3 This is another flow chart of the charging method of the bootstrap circuit provided in the embodiment of the present application.

[0079] In some embodiments, Figure 3As shown, step S110 performs at least one charging operation on the energy storage element with a preset charging unit time as a period, and may include steps S111 to S112.

[0080] S111, in response to a load start instruction, start an interrupt service.

[0081] Specifically, when a load start instruction is received, a corresponding interrupt service program may be triggered and started, and the load may be started after the interrupt service is completed.

[0082] S112, performing at least one charging operation on the energy storage element with a preset charging unit time as a period.

[0083] Specifically, after entering the interruption service, at least one charging operation may be performed on the energy storage element with a preset charging unit time length as the duration of one charging.

[0084] Step S140 ends charging when the effective charging time reaches the target total charging time, and may include step S141.

[0085] S141, when the effective charging time reaches the target total charging time, exit the interruption service and start the load.

[0086] Specifically, when the effective charging time of the energy storage element reaches the preset target total charging time, it means that the charging is completed. At this time, the load can be started after the interruption service is exited.

[0087] In other words, the embodiment of the present application is equivalent to Figure 1 Steps S110 to S140 in the embodiment are encapsulated in an interrupt service function, which is triggered upon receiving a motor start instruction. The interrupt service function is used to charge the bootstrap capacitor, and the motor is started after the capacitor is fully charged.

[0088] The bootstrap circuit charging method provided in the embodiment of the present application quickly starts the interrupt service program after receiving the load start instruction, and periodically charges the energy storage element with a preset charging unit duration during the interrupt service. After each charging operation, it can flexibly decide whether to directly perform the next charge or discharge first and then charge according to the comparison result of the load current and the rated value, thereby ensuring that the charging process is efficient and orderly. Once the effective charging time reaches the preset target total time, the interrupt service is immediately exited and the load is started. This mechanism not only optimizes the management of the charging process, but also ensures that the load can be started in time under the best condition, effectively avoiding the short-circuit current problem when the load is started, and ensuring the reliable start and operation of the load.

[0089] In some embodiments, the effective charging time of the energy storage element is the difference between the cumulative charging time and the cumulative discharging time, wherein the cumulative charging time is the product of the number of times the charging operation is performed and the preset charging unit time, and the cumulative discharging time is the product of the number of times the discharging operation is performed and the preset discharging unit time.

[0090] Specifically, the number of times the charging operation is performed can be multiplied by the preset charging unit time to obtain the cumulative charging time, and the number of times the discharging operation is performed can be multiplied by the preset discharging unit time to obtain the cumulative discharging time, and then the effective charging time of the energy storage element can be obtained by subtracting the cumulative charging time from the cumulative discharging time. For example, two counters can be used, one counter is used to count the number of times the charging operation is performed, and the other counter is used to count the number of times the discharging operation is performed.

[0091] The embodiment of the present application determines the effective charging time of the energy storage element by calculating the difference between the cumulative time of the charging operation and the cumulative time of the discharging operation, which can accurately reflect the actual charging state of the energy storage element. Once the effective charging time reaches the preset target total time, the interruption service is immediately exited and the load is started. This mechanism not only optimizes the management of the charging process, but also ensures that the load can be started in time under the best condition, effectively avoiding the short-circuit current problem when the load is started, and ensuring the reliable start-up and operation of the load.

[0092] In some embodiments, the preset charging unit time length is M times the preset discharging unit time length, where M is a real number greater than 1.

[0093] Wherein, M is a real number greater than 1, which is used to represent the proportional relationship between the preset charging unit time and the preset discharging unit time. The value of M can be adjusted according to the actual application scenario and the characteristics of the energy storage element to achieve the best charging and discharging effect.

[0094] Specifically, the preset charging unit time is M times the preset discharging unit time. For example, the preset charging unit time is 100us, and the preset discharging unit time is 50us, that is, each charging lasts 100us, and each discharging lasts 50us, and the preset charging unit time is twice the preset discharging unit time.

[0095] The embodiment of the present application sets the preset charging unit time to M times (M is a real number greater than 1) of the preset discharging unit time, that is, the duration of each charging is greater than the duration of each discharging. In other words, the charging speed of the storage element is greater than or equal to M times the discharging speed, which can optimize the charging efficiency while avoiding the short-circuit current problem when the load is started.

[0096] In some embodiments, a counter is used to calculate the effective charging time of the energy storage element;

[0097] Te=Cnt×Tc

[0098] Among them, Te is the effective charging time, Cnt is the value of the counter, Tc is the preset discharge unit time, the initial value of the counter is 0, the value of the counter is increased by M each time a charging operation is performed, and the value of the counter is decreased by 1 each time a discharging operation is performed.

[0099] Specifically, the effective charging time of the energy storage element can be calculated by a counter, the initial value of which is 0, and its value increases by M (M is the preset charging unit time divided by the preset discharge unit time) every time a charging operation is performed, and its value decreases by 1 every time a discharge operation is performed, and finally the effective charging time is determined by multiplying the value of the counter by the preset discharge unit time. For example, M = 2 (the preset charging unit time is twice the preset discharge unit time Tc), the preset discharge unit time Tc is 50us, the preset charging unit time is 100us, the initial value Cnt of the counter is 0, the value Cnt of the counter is increased by 2 every time a charging operation is performed, and the value Cnt of the counter is decreased by 1 every time a discharge operation is performed, and the effective charging time of the energy storage element Te = Cnt × Tc = Cnt × 50 is calculated after each charging operation.

[0100] The embodiment of the present application dynamically adjusts the value of the counter according to the number of charging operations and discharging operations, and calculates the effective charging time of the energy storage element in combination with the preset discharge unit time, so as to accurately calculate the actual charging effect of the energy storage element, and when the charging unit time is M times the discharge unit time (such as M=2), the effective charging time of the energy storage element is accurately calculated by counting the value of the counter by M after each charging operation and by 1 after each discharging operation.

[0101] Figure 4 This is another flow chart of the charging method of the bootstrap circuit provided in the embodiment of the present application.

[0102] In some embodiments, Figure 4 As shown, when the effective charging time reaches the target total charging time, before the charging is ended, the method further includes steps S151 to S153.

[0103] S151, charging at least one discharged energy storage element of the same type to obtain at least one piece of information on the time it takes to fully charge the energy.

[0104] Specifically, multiple discharged energy storage elements of the same type can be charged, and the time information required for each energy storage element to be fully charged, that is, the information on the time required to fully charge the energy storage element, can be recorded.

[0105] S152: Determine, from at least one piece of information on the time it takes to fully charge the battery, the longest time it takes to fully charge the battery as the total charging time.

[0106] Specifically, among multiple energy storage elements of the same model, the charging time corresponding to the energy storage element that takes the longest time to charge can be selected as the total charging time.

[0107] S153, multiplying the total charging time by a preset coefficient to obtain a target total charging time.

[0108] Among them, the preset coefficient can be a value greater than 1, for example, the preset coefficient can be 1.1, 1.2, etc., which can increase a certain charging time margin, reduce performance degradation or safety hazards caused by insufficient charging, and have higher reliability and safety.

[0109] The embodiment of the present application charges multiple discharged energy storage elements of the same type and records the longest full charging time, and then multiplies the time by a preset coefficient greater than 1 to obtain a longer target total charging time, thereby ensuring that the energy storage elements are fully charged, reducing performance degradation or safety hazards caused by insufficient charging, and improving the reliability and safety of the circuit.

[0110] Figure 5 This is another flow chart of the charging method of the bootstrap circuit provided in the embodiment of the present application.

[0111] In one example, if Figure 5 As shown, the charging method of the bootstrap circuit may include steps S01 to S09.

[0112] S01, charging at least one discharged energy storage element of the same type to obtain at least one piece of information on the time it takes to fully charge the energy.

[0113] S02: Determine, from at least one piece of information on charging time, the longest charging time as the total charging time.

[0114] S03: multiply the total charging time by a preset coefficient to obtain a target total charging time.

[0115] S04, in response to the load start instruction, start the interrupt service.

[0116] S05, performing at least one charging operation on the energy storage element with a preset charging unit time as a period.

[0117] S06, after each charging operation is completed, the effective charging time of the energy storage element is calculated and the current on the load side is detected.

[0118] S07, after the Nth charging operation is completed, when the current on the load side is greater than the preset rated current, a discharge operation is performed on the energy storage element according to a preset discharge unit time; after the discharge operation is completed, an N+1th charging operation is performed on the energy storage element.

[0119] S08, or, when the current on the load side is less than or equal to the preset rated current after the Nth charging operation is completed, performing the N+1th charging operation on the energy storage element.

[0120] S09, when the effective charging time reaches the target total charging time, exit the interruption service and start the load.

[0121] The embodiment of the present application ensures that the subsequent energy storage elements can be fully and safely charged by testing the longest charging time of the same type of energy storage elements and multiplying it by a preset coefficient, so as to determine the target total charging time. When the load needs to be started, it can respond quickly and start the interruption service, and charge the energy storage element multiple times with the preset charging unit time as the single charging duration. After each charging operation, the effective charging time can be calculated and the current on the load side can be monitored, and the charging strategy can be flexibly adjusted according to the current size: if the current exceeds the rated value, a short discharge operation is performed first to balance the current, and then charging continues; if the current does not exceed the rated value, the next charge is performed directly. This dynamic adjustment mechanism not only ensures the safe charging of the energy storage element, but also improves the charging efficiency. When the effective charging time reaches the preset target total charging time, the interruption service can be exited and the load can be started, thereby ensuring the safe startup of the load while ensuring the adequacy of charging, and improving the response speed and operation efficiency of the entire system.

[0122] Based on the same inventive concept, Figure 6 As shown, an embodiment of the present application further provides a controller 100, which may include: a processor 20 and a memory 10 storing computer program instructions; when the processor 20 executes the computer program instructions, the charging method of the bootstrap circuit as described in any of the above embodiments is implemented.

[0123] The controller 100 provided in the embodiment of the present application can realize Figures 1 to 5 The functions of each step of the charging method for the provided bootstrap circuit and the corresponding technical effects thereof are not described in detail here for the sake of brevity.

[0124] Based on the same inventive concept, Figure 7 As shown, the embodiment of the present application further provides a power consumption system 1000 , which may include: a bootstrap circuit 200 , a load 300 , and the controller 100 as described in the above embodiment.

[0125] The power consumption system 1000 includes the controller 100 provided by any one of the above embodiments, and thus the power consumption system 1000 has all the beneficial effects of the above controller 100 .

[0126] Figure 8It is a schematic diagram of the circuit structure of a bootstrap circuit 200 in a power system 1000 provided in an embodiment of the present application to drive single-phase upper and lower bridge arm switch tubes.

[0127] In one example, if Figure 8 As shown, PWM+ and PWM- are signals output by the controller to control the switch tube Q1 and the switch tube Q2. The PWM+ outputs a high level to control the switch tube Q1 to turn on, and a low level to control the switch tube Q1 to turn off. The PWM- outputs a high level to control the switch tube Q2 to turn on, and a low level to control the switch tube Q2 to turn off.

[0128] The switch tubes Q1 and Q2 may be insulated gate bipolar transistors (IGBTs). For example, if the voltage difference between the gate and emitter of the IGBT is greater than 15V, the IGBT will be turned on. Figure 8 The condition for Q2 to turn on is that the gate voltage of Q2 is greater than 15V (the emitter is referenced to the ground), while the condition for Q1 to turn on requires the gate voltage to be greater than the load side voltage of 15V.

[0129] Described below Figure 8 Steps to turn on Q1 and Q2 in the circuit:

[0130] 1) The controller controls PWM- to be high level and PWM+ to be low level. The PWM control integrated chip will output 15V to the gate of Q2, and Q2 will be turned on. The Vout and Vee port voltages of the single-tube driver integrated chip are equal, and Q1 is turned off.

[0131] Q2 is turned on and Q1 is turned off. The load side voltage is connected to the reference ground, and the 15V power supply will charge the energy storage element (capacitor C1) to 15V.

[0132] 2) The main control chip controls PWM+ to a high level and PWM- to a low level. The PWM control integrated chip will output the reference ground to the gate of Q2, and Q2 will be turned off. The single-tube driver integrated chip will keep the Vcc and Vout port voltages equal (Q1 gate voltage), so that the voltage difference between the gate and emitter of Q1 is 15V (the voltage difference between the two ends of C1), and Q1 is turned on.

[0133] The embodiment of the present application uses the PWM signal output by the controller to accurately control the on and off of the IGBT switch tubes Q1 and Q2, thereby achieving effective drive of the load. When Q2 is turned on, the power supply charges the energy storage element to prepare for the turn-on of Q1; and when Q1 is turned on, the charge stored in the energy storage element can ensure that Q1 can be turned on reliably.

[0134] The inventor has found that when using the bootstrap circuit to power the upper bridge IGBT driver, the lower bridge IGBT must be turned on first, and the capacitor C1 must be charged to 15V before the upper bridge IGBT can be controlled to turn on. Because the lower bridge IGBT must be turned on first, the bootstrap circuit can power the upper bridge IGBT driver (see Figure 8 ). Therefore, before the motor controller starts, it is necessary to control the three-phase lower bridge IGBT to be turned on first, so that the voltage across the three-phase bootstrap capacitor is charged to 15V, so that the upper bridge IGBT can be controlled to be turned on before the motor can be driven. Before the motor controller starts, if the three-phase lower bridge IGBT is controlled to be turned on at the same time, the three-phase windings of the motor are in a short-circuit state. At this time, if the motor speed is high, a large short-circuit current will be generated on the three phases of the motor, which may cause the motor controller to trigger overcurrent fault protection, and even cause the motor to demagnetize or the IGBT to break down.

[0135] Fig. 9 This is another circuit structure diagram of an electric power system 1000 provided in an embodiment of the present application.

[0136] In one example, if Fig. 9 As shown, the motor controller main control chip outputs 6 signals to control the charging of the three-phase drive bootstrap circuit 200. The charging method of the bootstrap circuit is implemented using software coding. Specifically:

[0137] 1) Make the motor stationary, the controller controls PWMU+, PWMV+, PWMW+ to low level, PWMU-, PWMV-, PWMW- to high level, use an oscilloscope to measure the time it takes for C1, C2, and C3 (the three have equal capacitance) to charge to 15V, that is, to obtain the information on the time it takes for each capacitor to be fully charged, and determine the longest time to fully charge as the total charging time Ts.

[0138] 2) The controller controls PWMU+, PWMV+, and PWMW+ to low levels, and PWMU-, PWMV-, and PWMW- to low levels. An oscilloscope is used to measure the time it takes for C1, C2, and C3 to discharge to 0V, thereby obtaining information about the discharge time of each capacitor. The minimum discharge time Td designed by the hardware is greater than 2*Ts.

[0139] 3) Drive the bootstrap circuit to charge.

[0140] It should be noted that the duration of an interruption cycle is 50us, the duration of a single discharge (preset discharge unit duration) is equal to the duration of the interruption cycle and is also 50us, and the duration of a single charge (preset charging unit duration) is 100us.

[0141] 3.1) After receiving the motor start command, the controller enters the interrupt service and drives the bootstrap circuit to charge.

[0142] 3.2) Start the interrupt service ISR1 with an interrupt period of 50us, and initialize the count value Cnt of the number of times ISR1 enters to 0.

[0143] 3.3) Enter ISR1 for the first time, control PWMU+, PWMV+, PWMW+ to low level, PWMU-, PWMV-, PWMW- to high level, and Cnt value increases by 2.

[0144] 3.4) Enter ISR1 for the kth time (k=2, 3, ...), if Cnt multiplied by Tc is greater than 1.1 times Ts, it means that the energy storage element is fully charged and go to step (3.6), otherwise execute step (3.5).

[0145] 3.5) Control PWMU+, PWMV+, and PWMW+ to a low level, and PWMU-, PWMV-, and PWMW- to a high level, and collect the maximum value Imax of the absolute value of the three-phase current of the motor; if Imax is less than the rated current of the motor, add 2 to the Cnt value and go to step (3.4); if Imax is greater than the rated current of the motor, control PWMU+, PWMV+, and PWMW+ to a low level, and PWMU-, PWMV-, and PWMW- to a low level, reduce the Cnt value by 1, and go to step (3.4).

[0146] 3.6) The main control chip controls PWMU+, PWMV+, and PWMW+ to a low level, and PWMU-, PWMV-, and PWMW- to a low level.

[0147] 3.7) End the drive bootstrap charging state and start motor driving.

[0148] The embodiment of the present application uses software control to drive the bootstrap circuit to charge. Without increasing the additional hardware cost, it can ensure that the motor is stationary or started at a speed, so that the bootstrap circuit can be charged. It also solves the problem of excessive short-circuit current in the motor caused by simultaneous charging of the three-phase drive bootstrap circuit when the motor is started at a speed.

[0149] It should be understood that in the embodiment of the present application, "B corresponding to A" means that B is associated with A, and B can be determined according to A. However, it should also be understood that determining B according to A does not mean determining B only according to A, and B can also be determined according to A and / or other information.

[0150] The above are only specific implementations of the present application, but the protection scope of the present application is not limited thereto. Any technician familiar with the technical field can easily think of various equivalent modifications or replacements within the technical scope disclosed in the present application, and these modifications or replacements should be included in the protection scope of the present application. Therefore, the protection scope of the present application shall be based on the protection scope of the claims.

Claims

1. A charging method for a bootstrap circuit, characterized in that: The bootstrap circuit includes an energy storage element, and the method includes: Performing at least one charging operation on the energy storage element with a preset charging unit time as a period; After each charging operation is completed, the effective charging time of the energy storage element is calculated and the current on the load side is detected; After the Nth charging operation is completed, according to the comparison result between the current on the load side and the preset rated current, the energy storage element is charged for the N+1th time or the energy storage element is discharged and then charged for the N+1th time, where N is an integer greater than or equal to 1; When the effective charging time reaches the target total charging time, the charging is terminated.

2. The method according to claim 1, characterized in that: The charging operation includes controlling the switch tube of the upper bridge arm in the bootstrap circuit to be disconnected, and controlling the switch tube of the lower bridge arm in the bootstrap circuit to be turned on; And / or, the discharging operation includes controlling the switch tube of the upper bridge arm and the switch tube of the lower bridge arm in the bootstrap circuit to be disconnected.

3. The method according to claim 1, characterized in that After the Nth charging operation is completed, according to the comparison result between the current on the load side and the preset rated current, the energy storage element is charged for the N+1th time or the energy storage element is discharged and then charged for the N+1th time, including: When the current on the load side is greater than the preset rated current after the Nth charging operation is completed, a discharge operation is performed on the energy storage element according to a preset discharge unit time; after the discharge operation is completed, an N+1th charging operation is performed on the energy storage element; or, When the current on the load side is less than or equal to the preset rated current after the Nth charging operation is completed, the N+1th charging operation is performed on the energy storage element.

4. The method according to claim 1, characterized in that: The step of performing at least one charging operation on the energy storage element with a preset charging unit time as a period includes: In response to a load start instruction, start interrupt service; Performing at least one charging operation on the energy storage element with a preset charging unit time as a period; When the effective charging time reaches the target total charging time, the charging is terminated, including: When the effective charging time reaches the target total charging time, the interruption service is exited and the load is started.

5. The method according to claim 1, characterized in that The effective charging time of the energy storage element is the difference between the cumulative charging time and the cumulative discharging time, wherein the cumulative charging time is the product of the number of executions of the charging operation and the preset charging unit time, and the cumulative discharging time is the product of the number of executions of the discharging operation and the preset discharging unit time.

6. The method according to claim 5, characterized in that The preset charging unit time length is M times the preset discharging unit time length, wherein M is a real number greater than 1.

7. The method according to claim 6, characterized in that Calculating the effective charging time of the energy storage element by using a counter; Te=Cnt×Tc Among them, Te is the effective charging time, Cnt is the value of the counter, Tc is the preset discharge unit time, the initial value of the counter is 0, the value of the counter is increased by M each time a charging operation is performed, and the value of the counter is decreased by 1 each time a discharging operation is performed.

8. The method according to any one of claims 1 to 7, characterized in that: When the effective charging time reaches the target total charging time, before the charging is terminated, the method further includes: Charging at least one of the energy storage elements of the same model after being discharged, and obtaining at least one piece of information on the time it takes to be fully charged; In the information of at least one full charge time, determine the full charge time that takes the longest time as the total charging time; The total charging time is multiplied by a preset coefficient to obtain a target total charging time.

9. A controller, characterized in that: The controller comprises: a processor and a memory storing computer program instructions; when the processor executes the computer program instructions, the charging method of the bootstrap circuit according to any one of claims 1 to 8 is implemented.

10. An electricity system, characterized in that: The system comprises: a bootstrap circuit, a load and the controller as claimed in claim 9.

Images