CN114421815B

CN114421815B - Brake control method, device, electronic equipment and storage medium

Info

Publication number: CN114421815B
Application number: CN202111650486.XA
Authority: CN
Inventors: 缪周; 秦向南
Original assignee: Midea Group Co Ltd; Guangdong Midea White Goods Technology Innovation Center Co Ltd; Midea Group Shanghai Co Ltd
Current assignee: Midea Group Co Ltd; Guangdong Midea White Goods Technology Innovation Center Co Ltd; Midea Group Shanghai Co Ltd
Priority date: 2021-12-30
Filing date: 2021-12-30
Publication date: 2023-10-24
Anticipated expiration: 2041-12-30
Also published as: CN114421815A

Abstract

The application discloses a brake control method, a brake control device, electronic equipment and a storage medium. The method comprises the following steps: under the condition that the target motor needs to be braked, acquiring the bus voltage of a motor controller connected with the target motor; according to the bus voltage, combining a first voltage threshold value and a second voltage threshold value, and controlling the motor controller to switch between a first braking mode and a second braking mode in a hysteresis control mode so as to enable the motor controller to brake the target motor; the first voltage threshold is greater than a supply voltage of the target motor; the second voltage threshold is greater than the first voltage threshold and less than a safe voltage of the target motor; in the first braking mode, the motor controller is capable of braking the target motor by reducing an input current of the target motor; in the second braking mode, the motor controller is capable of braking the target motor by shorting the target motor.

Description

Brake control method, device, electronic equipment and storage medium

Technical Field

The application relates to the technical field of motors (English can be expressed as a Motor), in particular to a braking control method, a braking control device, electronic equipment and a storage medium.

Background

In the related art, no matter the motor controller adopts the power grid alternating current power supply, the direct current power supply or the battery power supply, a bus capacitor is required to be arranged on the direct current bus side to realize the balance of energy conversion from the power supply side to the inverter side, and the voltage of the bus capacitor represents the bus voltage of the motor controller at the moment. However, in the motor control process, the too high bus voltage may damage devices such as a capacitor and an inverter, so that the motor controller may malfunction due to the too high bus voltage.

Disclosure of Invention

In order to solve the related technical problems, the embodiment of the application provides a brake control method, a brake control device, electronic equipment and a storage medium.

The technical scheme of the embodiment of the application is realized as follows:

the embodiment of the application provides a braking control method, which comprises the following steps:

under the condition that a target motor needs to be braked, acquiring bus voltage of a motor controller connected with the target motor;

according to the bus voltage, combining a first voltage threshold value and a second voltage threshold value, and controlling the motor controller to switch between a first braking mode and a second braking mode in a hysteresis control mode so as to enable the motor controller to brake the target motor; wherein the first voltage threshold is greater than a supply voltage of the target motor; the second voltage threshold is greater than the first voltage threshold and less than a safe voltage of the target motor; in the first braking mode, the motor controller is capable of braking the target motor by reducing an input current of the target motor; in the second braking mode, the motor controller is capable of braking the target motor by shorting the target motor.

In the above scheme, the controlling the motor controller to switch between the first braking mode and the second braking mode by combining the first voltage threshold and the second voltage threshold according to the bus voltage through hysteresis control includes:

when the motor controller is controlled to start braking, the motor controller is controlled to enter the first braking mode under the condition that the bus voltage is smaller than the second voltage threshold value, or the motor controller is controlled to enter the second braking mode under the condition that the bus voltage is larger than or equal to the second voltage threshold value;

when the bus voltage is greater than or equal to the second voltage threshold, controlling the motor controller to switch from the first braking mode to the second braking mode;

and when the bus voltage is smaller than or equal to the first voltage threshold value, controlling the motor controller to switch from the second braking mode to the first braking mode.

In the above scheme, the method further comprises:

when the motor controller is controlled to enter the first braking mode, a first current value and a second current value are determined; the first current value corresponds to the quadrature current of the target motor in the current control period; the second current value corresponds to the direct-axis current of the target motor in the current control period;

And controlling the switching state of a bridge arm of an inverter in the motor controller according to the first current value and the second current value, so that the motor controller inputs sinusoidal currents corresponding to the first current value and the second current value to the target motor.

In the above aspect, the determining the first current value includes:

determining a first rotating speed and a second rotating speed of the target motor in a current control period, and acquiring a third current value of the target motor in a previous control period; the first rotation speed represents the rotation speed corresponding to a rotation speed instruction required by the target motor to accelerate to a third rotation speed in a first time period; the second rotational speed characterizes an actual rotational speed of the target motor; the third rotational speed characterizes a target rotational speed of the target motor; the third current value corresponds to the quadrature current of the target motor in the last control period;

and determining the first current value according to the first rotating speed, the second rotating speed and the third current value.

In the above aspect, the determining the second current value includes:

determining a second rotating speed of the target motor in a current control period, and acquiring a fourth current value of the target motor in a previous control period; the second rotational speed characterizes an actual rotational speed of the target motor; the fourth current value corresponds to the direct-axis current of the target motor in the last control period;

Comparing the second rotating speed with a first rotating speed threshold value to obtain a comparison result; the first rotation speed threshold represents the lowest rotation speed of the target motor when weak magnetic control is needed;

and determining the second current value by using the fourth current value and a preset slope instruction according to the comparison result.

In the above solution, the determining, according to the comparison result, the second current value by using the fourth current value and a preset ramp instruction includes:

determining the second current value by using the fourth current value and a first ramp instruction when the comparison result indicates that the second rotating speed is larger than the first rotating speed threshold value; the second current value is less than the fourth current value;

or,

determining the second current value by using the fourth current value and a second ramp instruction when the comparison result indicates that the second rotating speed is smaller than or equal to the first rotating speed threshold value; the second current value is greater than the fourth current value.

In the above scheme, the method further comprises:

clipping the first current value by using a first current threshold value or a second current threshold value to obtain a clipped first current value; and clipping the second current value by using a third current threshold or a fourth current threshold to obtain a clipped second current value; the first current threshold represents the maximum quadrature current of the target motor; the second current threshold represents the minimum quadrature current of the target motor; the third current threshold characterizes a maximum direct-axis current of the target motor; the fourth current threshold characterizes a minimum direct-axis current of the target motor;

And controlling the switching state of a bridge arm of the inverter according to the limited first current value and the limited second current value.

In the above scheme, the method further comprises:

and when the motor controller is controlled to enter the second braking mode, controlling an upper bridge arm of an inverter in the motor controller to be closed, and controlling a lower bridge arm of the inverter to be fully opened so as to enable the target motor to be grounded through the lower bridge arm of the inverter to form a short circuit.

In the above scheme, the method further comprises:

determining a first rotating speed, a second rotating speed and a third rotating speed of the target motor in a current control period; the first rotation speed represents the rotation speed corresponding to a rotation speed instruction required by the target motor to accelerate to a third rotation speed in a first time period; the second rotational speed characterizes an actual rotational speed of the target motor; the third rotational speed characterizes a target rotational speed of the target motor;

and determining whether the target motor needs to be braked or determining whether braking is needed to be finished in the process of braking the target motor according to at least two rotating speeds of the first rotating speed, the second rotating speed and the third rotating speed.

In the above solution, the determining whether the target motor needs to be braked according to at least two rotational speeds of the first rotational speed, the second rotational speed, and the third rotational speed includes:

In the case where the first rotation speed is greater than the third rotation speed and the second rotation speed is greater than the third rotation speed, or in the case where the direction of the second rotation speed is opposite to the direction of the third rotation speed, it is determined that the target motor needs to be braked.

In the above aspect, the determining whether braking is needed to be finished in the process of braking the target motor according to at least two rotational speeds of the first rotational speed, the second rotational speed and the third rotational speed includes:

and determining that braking is required to be finished under the condition that the first rotating speed is equal to the third rotating speed and the second rotating speed is smaller than or equal to the third rotating speed.

The embodiment of the application also provides a brake control device, which comprises:

the first processing unit is used for acquiring bus voltage of a motor controller connected with a target motor under the condition that the target motor is determined to need to be braked;

the second processing unit is used for controlling the motor controller to switch between a first braking mode and a second braking mode in a hysteresis control mode according to the bus voltage and combining a first voltage threshold value and a second voltage threshold value so as to enable the motor controller to brake the target motor; wherein the first voltage threshold is greater than a supply voltage of the target motor; the second voltage threshold is greater than the first voltage threshold and less than a safe voltage of the target motor; in the first braking mode, the motor controller is capable of braking the target motor by reducing an input current of the target motor; in the second braking mode, the motor controller is capable of braking the target motor by shorting the target motor.

The embodiment of the application also provides electronic equipment, which comprises: a processor and a memory for storing a computer program capable of running on the processor,

wherein the processor is configured to execute the steps of any of the methods described above when the computer program is run.

The embodiment of the application also provides a storage medium, on which a computer program is stored, which when executed by a processor, implements the steps of any of the methods described above.

According to the braking control method, the device, the electronic equipment and the storage medium provided by the embodiment of the application, under the condition that a target motor needs to be braked, the bus voltage of a motor controller connected with the target motor is obtained; according to the bus voltage, combining a first voltage threshold value and a second voltage threshold value, and controlling the motor controller to switch between a first braking mode and a second braking mode in a hysteresis control mode so as to enable the motor controller to brake the target motor; wherein the first voltage threshold is greater than a supply voltage of the target motor; the second voltage threshold is greater than the first voltage threshold and less than a safe voltage of the target motor; in the first braking mode, the motor controller is capable of braking the target motor by reducing an input current of the target motor; in the second braking mode, the motor controller is capable of braking the target motor by shorting the target motor. According to the scheme of the embodiment of the application, according to the bus voltage of the motor controller, the motor controller is controlled to switch between current braking control (namely a first braking mode) and short-circuit braking control (namely a second braking mode) in a hysteresis control mode by combining two voltage thresholds which are larger than the power supply voltage of the target motor and smaller than the safety voltage of the target motor, so that the combination of the two braking control modes of the current braking control and the short-circuit braking control is realized; therefore, the bus voltage margin of the motor controller and the characteristics of the target motor can be utilized to the greatest extent, the target motor can be rapidly and effectively braked on the premise that the bus voltage of the motor controller does not exceed the safety voltage of the target motor, and faults of the motor controller caused by overhigh bus voltage are avoided, so that the efficiency and safety of braking the target motor are improved.

Drawings

FIG. 1 is a schematic flow chart of a brake control method according to an embodiment of the present application;

FIG. 2 is a schematic flow chart of motor braking control according to an embodiment of the present application;

FIG. 3 is a schematic flow chart of hysteresis control according to an embodiment of the present application;

FIG. 4 is a schematic diagram showing the variation trend of the brake control method according to the embodiment of the present application;

FIG. 5 is a flow chart of generating a quadrature current command (i.e., a first current value) in a current braking control according to an embodiment of the present application;

FIG. 6 is a flow chart of generating a direct current command (i.e., a second current value) in a current braking control according to an embodiment of the present application;

FIG. 7 is a schematic diagram of a short circuit brake control according to an embodiment of the present application;

FIG. 8 is a schematic diagram of a brake control apparatus according to an embodiment of the present application;

fig. 9 is a schematic structural diagram of an electronic device according to an embodiment of the application.

Detailed Description

The present application will be described in further detail with reference to the accompanying drawings and examples.

In the related art, taking vector control as an example in motor control, in a deceleration braking state, it is generally necessary to set the motor quadrature current Iq to 0 or a current opposite to the motor rotation speed. When Iq is a reverse current, the motor output torque is opposite to the rotation speed direction, so that the motor operates as a generator, energy is output to a bus, the bus voltage is further increased, and if protection and control are not performed, a motor controller (such as a frequency converter) can generate faults due to overhigh bus voltage. At this time, it is considered that extra braking devices such as a braking unit and a braking resistor are connected to the dc bus of the motor controller to consume excessive power generation energy. However, adding a brake unit, a brake resistor, and other brake devices to the motor controller increases the volume and cost of the motor controller, and causes problems such as heat dissipation and installation.

In addition, some motor control scenarios have special demands on motor control beats (i.e., control cycles), which may require increasing the starting and braking speeds of the motor. In the braking process, the speed of motor deceleration can be increased by increasing the reverse Iq, however, the bus voltage of the motor controller can also be increased more quickly along with the change of the Iq, and the reverse Iq needs to be reduced to improve the braking safety, so that the problem of insufficient braking speed is caused.

Based on the above, in various embodiments of the present application, according to the bus voltage of the motor controller, in combination with two voltage thresholds that are greater than the power supply voltage of the target motor and less than the safety voltage of the target motor, the motor controller is controlled to switch between the current braking control and the short-circuit braking control by the hysteresis control manner, so that the combination of the two braking control manners of the current braking control and the short-circuit braking control is realized; therefore, no additional braking equipment such as a braking unit and a braking resistor is required to be arranged in the motor controller, the bus voltage allowance of the motor controller and the characteristics of the target motor can be utilized to the greatest extent, the target motor is rapidly and effectively braked on the premise that the bus voltage of the motor controller does not exceed the safety voltage of the target motor, and faults caused by the fact that the bus voltage of the motor controller is too high are avoided, so that the efficiency and the safety of the target motor are improved.

An embodiment of the present application provides a braking control method, applied to an electronic device, as shown in fig. 1, where the method includes:

step 101: under the condition that a target motor needs to be braked, acquiring bus voltage of a motor controller connected with the target motor;

step 102: according to the bus voltage, combining a first voltage threshold value and a second voltage threshold value, and controlling the motor controller to switch between a first braking mode and a second braking mode in a hysteresis control mode so as to enable the motor controller to brake the target motor;

wherein the first voltage threshold is greater than a supply voltage of the target motor; the second voltage threshold is greater than the first voltage threshold and less than a safe voltage of the target motor; in the first braking mode, the motor controller is capable of braking the target motor by reducing an input current of the target motor; in the second braking mode, the motor controller is capable of braking the target motor by shorting the target motor.

In practical application, the electronic device may be provided with the target motor and the motor controller inside, or the electronic device may be connected to the target motor and the motor controller through an external circuit. The structure among the electronic device, the target motor and the motor controller can be specifically set according to requirements, and the embodiment of the application is not limited to this.

In actual application, the first braking mode may also be referred to as current braking control; the second braking mode may also be referred to as a short circuit braking control; the names of the first braking mode and the second braking mode are not limited in the embodiment of the application, so long as the braking principle of the first braking mode and the second braking mode can be realized.

In practical applications, the decreasing the input current of the target motor may include increasing the input current of the target motor in a negative direction, in other words, the input current of the target motor may be a positive current (i.e., the current value is a positive number) or a negative current (i.e., the current value is a negative number). In the first braking mode, the motor controller may either decrease the positive input current of the target motor or increase the negative input current of the target motor.

In practical application, the motor controller can comprise a capacitor, an inverter and other devices; the electronic equipment can specifically control the motor controller to brake the target motor by controlling the switch state of a bridge arm of the inverter. It will be appreciated that the electronic device needs to control the motor controller in real time to achieve real-time control of the target motor, where there is a control beat (which may also be referred to as a control beat), in other words, the electronic device needs to periodically control the switching state of the bridge arm of the inverter to control the motor controller to brake the target motor. Here, the specific control period of the electronic device to control the switching state of the bridge arm of the inverter may be set according to requirements, for example, 100 microseconds (μs), which is not limited by the embodiment of the present application.

In actual application, before executing step 101, it may be determined whether to brake the target motor according to the rotation speed of the target motor, and step 101 may be executed when it is determined that the target motor needs to be braked.

Based on this, in an embodiment, the method may further include:

Here, it can be understood that the electronic device needs to acquire the first rotation speed, the second rotation speed, and the third rotation speed in each control period, determine whether braking of the target motor is required or determine whether braking is required to be ended in the process of braking the target motor according to at least two rotation speeds of the first rotation speed, the second rotation speed, and the third rotation speed, so as to implement real-time control of the target motor.

In practical application, the target rotation speed can be understood as the rotation speed which the user hopes the target motor to reach, is an external input parameter, and can be specifically set according to the requirement; in other words, the electronic device may obtain the third rotation speed from a local profile or other electronic devices.

In practical application, the electronic device may sample (i.e. detect) information such as current and voltage of the target motor, and calculate the second rotation speed in combination with a preset algorithm (which may be set according to the requirement).

In practical application, the first rotation speed is determined based on the second rotation speed and the third rotation speed, and the first duration can be set according to requirements, such as 4 seconds(s), 5s, and the like. Specifically, after the electronic device determines the second rotation speed and the third rotation speed, the first rotation speed may be calculated by using the second rotation speed, the third rotation speed and the first duration and combining a preset algorithm (which may be set according to requirements). Here, the rotation speed command is a virtual quantity, does not refer to a physical signal, and can be understood as an intermediate variable inside an algorithm, and the electronic device controls the motor controller based on the rotation speed command, so that the target motor can reach the third rotation speed from the second rotation speed within the first duration.

In practical application, the first rotation speed may also be referred to as a command rotation speed; the second rotational speed may also be referred to as a feedback rotational speed; the third rotational speed may also be referred to as a target rotational speed; the names of the first rotation speed, the second rotation speed and the third rotation speed are not limited in the embodiment of the application.

In an embodiment, the determining whether the target motor needs to be braked according to at least two speeds of the first speed, the second speed and the third speed may include:

Here, the direction of the second rotation speed is opposite to the direction of the third rotation speed, which means that the values of the second rotation speed and the third rotation speed are opposite to each other, that is, one rotation speed value of the second rotation speed and the third rotation speed is positive, and the other rotation speed value is negative.

When the motor is actually applied, after determining that the target motor needs to be braked, the electronic device can detect the bus voltage of the motor controller, namely, step 101 is executed. Here, the specific manner in which the electronic device detects the bus voltage of the motor controller may be set according to needs, which is not limited by the embodiment of the present application.

In an embodiment, the determining whether braking is required to be finished in the process of braking the target motor according to at least two rotational speeds of the first rotational speed, the second rotational speed and the third rotational speed may include:

In practical application, after determining that braking needs to be finished, the electronic device may control the motor controller to perform other control flows, which is not limited by the embodiment of the present application.

In step 102, during actual application, the first voltage threshold and the second voltage threshold are external input parameters, which can be specifically set according to requirements; in other words, the electronic device may obtain the first voltage threshold and the second voltage threshold from a local profile or other electronic device.

In practical application, the power supply voltage and the safety voltage of the target motor are determined by the characteristics of the target motor, and can be specifically set according to requirements, which is not limited by the embodiment of the application.

In an embodiment, the controlling the motor controller to switch between the first braking mode and the second braking mode by hysteresis control according to the bus voltage and in combination with the first voltage threshold and the second voltage threshold may include:

in the first braking mode, when the bus voltage is greater than or equal to the second voltage threshold, controlling the motor controller to switch from the first braking mode to the second braking mode;

and in the second braking mode, when the bus voltage is smaller than or equal to the first voltage threshold value, controlling the motor controller to switch from the second braking mode to the first braking mode.

When the bus voltage reaches the second voltage threshold value, the motor controller is controlled to enter the second braking mode in the process that the electronic equipment periodically controls the motor controller to brake the target motor; in the second braking mode, the target motor is short-circuited, so that loops are not generated on two sides of a bus capacitor in the motor controller, and bus voltage is reduced along with natural consumption of capacitor energy; therefore, in the process of braking the target motor, the bus voltage of the motor controller does not exceed the second voltage threshold, namely the safety voltage of the target motor, so that faults of the motor controller caused by overhigh bus voltage can be avoided, and the efficiency and safety of braking the target motor can be improved.

In actual application, in the first braking mode, the electronic device may control the target motor in a vector control manner, that is, control the quadrature axis current and the direct axis current of the target motor.

Based on this, in an embodiment, the method may further include:

In practical application, the first current value and the second current value may also be referred to as current instructions, where the current instructions are virtual quantities, and not physical signals, and may be understood as intermediate variables inside an algorithm.

In practical application, the bridge arm of the inverter may also be referred to as a bridge arm power switch tube, and controlling the switch state of the bridge arm of the inverter may be understood as controlling the switch degree of the bridge arm of the inverter. Specifically, after the electronic device determines the first current value and the second current value, a preset algorithm, such as a space vector pulse width modulation (SVPWM, space Vector Pulse Width Modulation) algorithm, may be used to determine the digital signal that needs to be output to the bridge arm of the inverter. Here, the digital signal ranges from 0 to 1; when the digital signal is 0, the bridge arm of the inverter is closed, namely, the inverter is completely turned off; and when the digital signal is 1, all bridge arms of the inverter are opened, namely, are completely conducted.

In an embodiment, the determining the first current value may include:

acquiring a third current value of the target motor in a previous control period; the third current value corresponds to the quadrature current of the target motor in the last control period;

In practical application, the electronic device may determine the first current value according to the first rotation speed, the second rotation speed, and the third current value by using a preset algorithm, such as a PI control algorithm, a quasi-PR control algorithm, and the like. Here, the preset algorithm may be provided in the electronic device in the form of a digital controller, such as a PI controller, a quasi-PR controller, or the like.

In an embodiment, the determining the second current value may include:

acquiring a fourth current value of the target motor in a previous control period; the fourth current value corresponds to the direct-axis current of the target motor in the last control period;

Here, since the direct-axis current of the target motor corresponds to the field weakening control, the minimum rotation speed when the target motor requires the field weakening control may be understood as 0 when the rotation speed of the target motor is less than the minimum rotation speed.

In practical application, the first rotation speed threshold is an external input parameter and can be set according to the characteristics of the target motor; in other words, the electronic device may obtain the first rotation speed threshold from a local profile or other electronic device.

In practical application, the ramp instruction can be set according to requirements, and is used for enabling the second current value to be gradually increased or gradually decreased according to the corresponding slope.

Based on this, in an embodiment, the determining the second current value according to the comparison result using the fourth current value and a preset ramp instruction may include:

Or,

In practical application, in order to further improve the efficiency and safety of braking the target motor, after determining the first current value and the second current value, the electronic device may limit the first current value and the second current value by using a preset current threshold, and then control the switching state of the bridge arm of the inverter according to the limited first current value and limited second current value.

Based on this, in an embodiment, the method may further include:

Correspondingly, the controlling the switching state of the bridge arm of the inverter in the motor controller according to the first current value and the second current value may include:

Here, the first current threshold value, the second current threshold value, the third current threshold value, and the fourth current threshold value are external input parameters, and may be specifically set according to requirements; in other words, the electronic device may obtain the first current threshold, the second current threshold, the third current threshold, and the fourth current threshold from a local profile or other electronic device.

In practical applications, the first current threshold, the second current threshold, the third current threshold and the fourth current threshold may be thresholds for absolute values of currents, in other words, the first current value and the second current value may be clipped based on absolute values of the first current value and the second current value.

In actual application, in the second braking mode, the electronic device may close an upper bridge arm of the inverter, so as to short-circuit the target motor.

Based on this, in an embodiment, the method may further include:

When the target motor is short-circuited, loops are not generated on two sides of a bus capacitor in the motor controller, so that bus voltage of the motor controller can be reduced along with natural consumption of capacitor energy, and when the bus voltage is reduced to the first voltage threshold, namely when the bus voltage is smaller than or equal to the first voltage threshold, the electronic equipment controls the motor controller to be switched from the second braking mode to the first braking mode. In the first braking mode, the first current value may be opposite to the rotation speed direction of the target motor, that is, the first current value may be negative, so that the target motor generates electricity, thereby causing the bus voltage to rise, and in the case that the bus voltage reaches the second voltage threshold, that is, when the bus voltage is greater than or equal to the second voltage threshold, the electronic device controls the motor controller to switch from the first braking mode to the second braking mode. It can be seen that the electronic device controls the motor controller to switch between the first braking mode and the second braking mode in a hysteresis control manner, and is a cyclic control, namely loop control, until the target motor is successfully braked; in this way, the efficiency and safety of braking the target motor can be improved.

In practical application, the electronic device may send a digital signal with a value of 0 to an upper bridge arm of the inverter, so as to control the upper bridge arm of the inverter to be closed; and a digital signal with a value of 1 can be sent to the lower bridge arm of the inverter to control the lower bridge arm of the inverter to be fully opened (i.e., fully conducted). At this time, the quadrature current of the target motor is 0.

When the motor braking device is in practical application, after the target motor is short-circuited, the phase current of the target motor is increased to the characteristic current of the target motor, so that the motor braking can be accelerated by increasing the copper consumption of the target motor, namely the efficiency of braking the target motor is improved.

According to the braking control method provided by the embodiment of the application, under the condition that a target motor needs to be braked, the bus voltage of a motor controller connected with the target motor is obtained; according to the bus voltage, combining a first voltage threshold value and a second voltage threshold value, and controlling the motor controller to switch between a first braking mode and a second braking mode in a hysteresis control mode so as to enable the motor controller to brake the target motor; wherein the first voltage threshold is greater than a supply voltage of the target motor; the second voltage threshold is greater than the first voltage threshold and less than a safe voltage of the target motor; in the first braking mode, the motor controller is capable of braking the target motor by reducing an input current of the target motor; in the second braking mode, the motor controller is capable of braking the target motor by shorting the target motor. According to the scheme of the embodiment of the application, according to the bus voltage of the motor controller, the motor controller is controlled to switch between the current braking control and the short-circuit braking control in a hysteresis control mode by combining two voltage thresholds which are larger than the power supply voltage of the target motor and smaller than the safety voltage of the target motor, so that the combination of the two braking control modes of the current braking control and the short-circuit braking control is realized; therefore, no additional braking equipment such as a braking unit and a braking resistor is required to be arranged in the motor controller, the bus voltage allowance of the motor controller and the characteristics of the target motor can be utilized to the greatest extent, the target motor is rapidly and effectively braked on the premise that the bus voltage of the motor controller does not exceed the safety voltage of the target motor, and faults caused by the fact that the bus voltage of the motor controller is too high are avoided, so that the efficiency and the safety of the target motor are improved.

The present application will be described in further detail with reference to examples of application.

In the present application embodiment, the first braking mode is referred to as current braking control; the second braking mode is called short-circuit braking control; the bus voltage of the motor controller is denoted Udc; the first voltage threshold is denoted Udc1; the second voltage threshold is denoted Udc2; the control period is called a control beat; the first current value is called a quadrature current command, denoted iq_ref; the second current value is referred to as a direct current command, denoted id_ref; the first rotational speed is referred to as a command rotational speed, denoted ω_ref; the second rotational speed is referred to as a feedback rotational speed, denoted ω_ fdb; the third rotational speed is referred to as a target rotational speed; the first rotational speed threshold is denoted as n_fw.

The embodiment of the application provides a motor control system which comprises a control chip (namely the electronic equipment), a motor controller and a motor, wherein the motor controller and the motor are connected with the control chip. As shown in fig. 2, when the motor control system starts braking, the control chip collects needed critical voltage values Udc1 and Udc2 in a user input mode, and judges whether to enter a braking process according to the magnitude relation among the target rotating speed, the command rotating speed and the feedback rotating speed of the motor; after judging that the braking process is carried out, the control chip adopts a hysteresis control method according to the magnitude of the bus voltage to control the motor controller to switch between current braking control and short circuit braking control, and then judges whether to exit braking or continue hysteresis braking control according to the magnitude relation among the target rotating speed, the command rotating speed and the feedback rotating speed, so that the whole braking control loop is realized.

In this application embodiment, the motor braking control flow specifically includes the following steps:

step 1: the user inputs to the control chip the busbar voltages Udc1 and Udc2 for controlling the method switching (i.e. controlling the switching between the two braking control modes), and the supply voltage < Udc1< Udc2< safety voltage.

Step 2: the control chip judges the braking state, and when the command rotating speed is higher than the target rotating speed and the feedback rotating speed is higher than the target rotating speed under the current control beat, the system enters a braking working state; or when the rotating speed feedback is opposite to the target rotating speed direction, the system enters a braking working state.

Step 3: when the motor starts to enter a braking process, the motor is switched from a starting state or a steady state to a braking state, the initial value of the bus voltage is usually near the power supply voltage, and the control chip performs current braking control, namely, a vector control method is adopted to control the quadrature axis current command Iq_ref and the direct axis current command Id_ref of the motor. Here, the step 3 specifically includes the following two steps:

1) As shown in fig. 5, for the quadrature current command iq_ref, it is necessary to calculate a proportional portion (hereinafter referred to as proportional value) and an integral portion (hereinafter referred to as integral value) thereof by a PI control algorithm based on the difference between the command rotational speed and the feedback rotational speed. Wherein the proportional value ωerr (k) is calculated by the following formula:

ωErr(k)＝ω_ref-ω_fdb (1)

Here, k represents the current control beat.

The integral value DeltaErr (k) is calculated by the following formula:

DeltaErr(k)＝ωErr(k)-ωErr(k-1) (2)

here, ωerr (k-1) represents the scale value of the last control beat.

After the proportional value and the integral value are determined by the formula (1) and the formula (2), the proportional value and the integral value are multiplied by the corresponding proportional coefficient and the integral coefficient respectively by the formula (3) and the formula (4), and then the non-limiting quadrature current instruction Iq_ref' (k) is calculated by the formula (5).

Iq_P＝Kp*DeltaErr(k) (3)

Iq_I＝Ki*ωErr(k) (4)

Iq_ref’(k)＝Iq_ref’(k-1)+Iq_P+Iq_I (5)

Wherein Kp represents an integral coefficient; ki represents a scaling factor; kp and Ki can be set by a user according to requirements; iq_ref' (k-1) represents the quadrature current command (i.e., the third current value) of the previous control beat.

Finally, the quadrature current command iq_ref' (k) calculated by the PI control algorithm is limited, so that the absolute value of the quadrature current command does not exceed the maximum value (i.e., the first current threshold and the second current threshold) in the control system, and the limited quadrature current command iq_ref is obtained.

2) As shown in fig. 6, for the direct current command id_ref, the actual rotation speed ω_ fdb of the motor needs to be compared with the rotation speed n_fw of the motor that needs to be magnetically weak, and id_ref needs to be controlled based on the comparison result.

If ω_ fdb is greater than n_fw, id_ref is gradually reduced by a ramp command (i.e., the first ramp command) to obtain an unclamped direct-axis current command id_ref' (out) for each control beat, compared with a direct-axis current command id_ref (in) of the previous control beat (i.e., the fourth current value), so that the field weakening depth of the motor is deeper, and then the amplitude limiting is performed to obtain a direct-axis current command not less than the minimum direct-axis current of the motor (i.e., the fourth current threshold value), so as to obtain a new direct-axis current command id_ref (out) for actual current loop control and as an input of the next control beat.

If ω_ fdb is less than or equal to n_fw, the id_ref is gradually increased by the ramp command (i.e., the second ramp command) to obtain an unclamped direct-axis current command id_ref' (out) for each control beat compared with the direct-axis current command id_ref (in) of the previous control beat, so that the motor gradually jumps out of the field weakening region, and the direct-axis current command is not greater than the maximum direct-axis current (i.e., the third current threshold) of the motor after clipping, so as to obtain a new direct-axis current command id_ref (out) for actual current loop control and serve as an input of the next control beat.

Step 4: under the current braking control, iq_ref may be opposite to the rotational speed direction of the motor, so that the motor generates electricity, thereby raising the bus voltage; at this time, as shown in fig. 3 and 4, the control chip needs to perform bus voltage judgment, that is, judge the magnitude relation between Udc and Udc2, and control the switching of the braking control mode based on the judgment result; if the Udc is smaller than Udc2, continuing the current braking control of the step 3; if Udc is greater than or equal to Udc2, the short circuit braking control of step 5 is performed.

Step 5: the control chip performs short-circuit braking control, closes an upper bridge arm of a multiphase bridge arm of an inverter in the motor controller, and fully opens (i.e. fully conducts) a lower bridge arm, so that a multiphase winding of the motor is grounded through a corresponding lower bridge arm to form a short circuit, thereby increasing phase current of the motor to characteristic current of the motor, and accelerating motor braking by increasing copper consumption of the motor.

Illustratively, as shown in FIG. 7, an upper leg U in an inverter three-phase wall _H 、V _H 、W _H All are closed, lower bridge arm U _L 、V _L 、W _L All the motor three-phase windings are opened and short-circuited with each other through the corresponding lower bridge arm.

Step 6: as shown in fig. 7, under the short circuit braking control, no loop is generated on both sides of the bus capacitor C in the motor controller, so that the bus voltage is reduced along with the natural consumption of the capacitor energy; at this time, as shown in fig. 3 and 4, the control chip needs to perform bus voltage judgment, that is, judge the magnitude relation between Udc and Udc1, and control the switching of the braking control mode based on the judgment result; if the Udc is greater than Udc1, continuing the short circuit braking control of the step 5; and if the Udc is less than or equal to Udc1, returning to the current braking control of the step 3.

Step 7: the control chip judges the rotation speed to determine whether the braking process is finished, when the instruction rotation speed reaches the target rotation speed (namely omega_ref is equal to the target rotation speed) and the feedback rotation speed is equal to or lower than the target rotation speed, the control chip judges that the braking process is finished, other control flows are carried out, otherwise, the steps 3 to 6 are continuously executed, and the motor braking is realized in a hysteresis control mode.

In practical application, for a general motor, the speed of current braking control is faster or the speed of short-circuit braking control is faster, and depends on parameters such as characteristic current, running rotating speed, rated bus voltage and the like of the motor, and after the bus voltage rises, the speed of current braking control is also influenced. Therefore, according to the scheme of the application embodiment, the control chip combines the current braking control and the short-circuit braking control together in a hysteresis control mode according to the bus voltage of the motor controller, so that the bus voltage margin of the motor controller and the self characteristics of the motor can be utilized to the maximum extent, the rapid shutdown of the motor can be realized, the bus voltage of the motor controller is protected from overvoltage, and the method is an efficient and safe braking method.

Here, the control chip protects the bus voltage of the motor controller from overvoltage due to the supply voltage < Udc1< Udc2< safety voltage, and, in the process of braking the motor, once Udc reaches Udc2, the motor control system enters short-circuit braking control; in other words, the maximum value Udc2 that Udc can reach during the entire braking control process is not exceeded by the safety voltage threshold of the control system. Therefore, the control chip can not only protect the bus voltage of the motor controller from being too high, but also effectively and rapidly stop the motor, thereby realizing rapid, effective and safe braking of the motor.

In order to implement the method of the embodiment of the application, the embodiment of the application also provides a brake control device which is arranged on the electronic equipment, wherein the electronic equipment is internally provided with a target motor and a motor controller or is connected with the target motor and the motor controller through an external circuit; as shown in fig. 8, the apparatus includes:

a first processing unit 801, configured to obtain a bus voltage of a motor controller connected to a target motor in a case where it is determined that the target motor needs to be braked;

a second processing unit 802, configured to control, by using hysteresis control, the motor controller to switch between a first braking mode and a second braking mode according to the bus voltage in combination with a first voltage threshold and a second voltage threshold, so that the motor controller brakes the target motor; wherein the first voltage threshold is greater than a supply voltage of the target motor; the second voltage threshold is greater than the first voltage threshold and less than a safe voltage of the target motor; in the first braking mode, the motor controller is capable of braking the target motor by reducing an input current of the target motor; in the second braking mode, the motor controller is capable of braking the target motor by shorting the target motor.

In one embodiment, the second processing unit 802 is specifically configured to:

In an embodiment, the second processing unit 802 is further configured to:

or,

In an embodiment, the second processing unit 802 is further configured to:

In an embodiment, the second processing unit 802 is further configured to control, when the motor controller enters the second braking mode, to control an upper bridge arm of an inverter in the motor controller to be closed, and to control a lower bridge arm of the inverter to be fully opened, so that the target motor is grounded through the lower bridge arm of the inverter to form a short circuit.

In an embodiment, the first processing unit 801 is further configured to:

In an embodiment, the first processing unit 801 is further configured to determine that the target motor needs to be braked when the first rotational speed is greater than the third rotational speed and the second rotational speed is greater than the third rotational speed, or when the direction of the second rotational speed is opposite to the direction of the third rotational speed.

In an embodiment, the first processing unit 801 is further configured to determine that braking is required to be ended when the first rotational speed is equal to the third rotational speed and the second rotational speed is less than or equal to the third rotational speed.

Here, the function of the brake control device corresponds to the function of the control chip in the application embodiment of the present application.

In practical applications, the first processing unit 801 and the second processing unit 802 may be implemented by a processor in the brake control device in combination with a communication interface.

It should be noted that: the brake control device provided in the above embodiment is exemplified by the above-described division of each program module when controlling the motor controller to brake the target motor, and in practical application, the above-described process allocation may be performed by different program modules according to needs, i.e., the internal structure of the device is divided into different program modules to complete all or part of the above-described processes. In addition, the brake control device and the brake control method provided in the foregoing embodiments belong to the same concept, and specific implementation processes thereof are detailed in the method embodiments and are not described herein again.

The embodiment of the application also provides electronic equipment, wherein the electronic equipment is internally provided with a target motor and a motor controller or is connected with the target motor and the motor controller through an external circuit; as shown in fig. 9, the electronic device 900 includes:

the communication interface 901 can perform information interaction with other electronic devices;

the processor 902 is connected with the communication interface 901 to realize information interaction with other electronic devices, and is used for executing the methods provided by one or more of the technical schemes when running the computer program;

a memory 903 stores a computer program capable of running on the processor 902.

Specifically, the processor 902 is configured to:

Wherein, in an embodiment, the processor 902 is further configured to:

In an embodiment, the processor 902 is further configured to:

or,

In an embodiment, the processor 902 is further configured to:

In an embodiment, the processor 902 is further configured to control, when the motor controller enters the second braking mode, to control an upper bridge arm of an inverter in the motor controller to be closed, and to control a lower bridge arm of the inverter to be fully opened, so that the target motor is grounded through the lower bridge arm of the inverter to form a short circuit.

In an embodiment, the processor 902 is further configured to:

In an embodiment, the processor 902 is further configured to determine that the target motor needs to be braked when the first rotational speed is greater than the third rotational speed and the second rotational speed is greater than the third rotational speed, or when the direction of the second rotational speed is opposite to the direction of the third rotational speed.

In an embodiment, the processor 902 is further configured to determine that braking is required to be ended when the first rotational speed is equal to the third rotational speed and the second rotational speed is less than or equal to the third rotational speed.

It should be noted that: the details of the process of the processor 902 for executing the above operations are detailed in the method embodiment, and are not described herein.

Of course, in actual practice, the various components in electronic device 900 are coupled together by bus system 904. It is appreciated that the bus system 904 is used to facilitate connected communications between these components. The bus system 904 includes a power bus, a control bus, and a status signal bus in addition to a data bus. But for clarity of illustration, the various buses are labeled as bus system 904 in fig. 9.

The memory 903 in embodiments of the present application is used to store various types of data to support the operation of the electronic device 900. Examples of such data include: any computer program for operating on the electronic device 900.

The method disclosed in the above embodiment of the present application may be applied to the processor 902 or implemented by the processor 902. The processor 902 may be an integrated circuit chip having signal processing capabilities. In implementation, the steps of the methods described above may be performed by integrated logic circuitry in hardware or instructions in software in the processor 902. The processor 902 may be a general purpose processor, a digital signal processor (DSP, digital Signal Processor), or other programmable logic device, discrete gate or transistor logic device, discrete hardware components, or the like. The processor 902 may implement or perform the methods, steps, and logic blocks disclosed in embodiments of the present application. The general purpose processor may be a microprocessor or any conventional processor or the like. The steps of the method disclosed in the embodiment of the application can be directly embodied in the hardware of the decoding processor or can be implemented by combining hardware and software modules in the decoding processor. The software modules may be located in a storage medium in the memory 903. The processor 902 reads information in the memory 903 and, in combination with its hardware, performs the steps of the method described above.

In an exemplary embodiment, the electronic device 900 may be implemented by one or more application specific integrated circuits (ASIC, application Specific Integrated Circuit), DSPs, programmable logic devices (PLD, programmable Logic Device), complex programmable logic devices (CPLD, complex Programmable Logic Device), field-programmable gate arrays (FPGA, field-Programmable Gate Array), general purpose processors, controllers, microcontrollers (MCU, micro Controller Unit), microprocessors (Microprocessor), or other electronic components for performing the aforementioned methods.

It will be appreciated that the memory 903 of embodiments of the application can be either volatile memory or nonvolatile memory, and can include both volatile and nonvolatile memory. Wherein the nonvolatile Memory may be Read Only Memory (ROM), programmable Read Only Memory (PROM, programmable Read-Only Memory), erasable programmable Read Only Memory (EPROM, erasable Programmable Read-Only Memory), electrically erasable programmable Read Only Memory (EEPROM, electrically Erasable Programmable Read-Only Memory), magnetic random access Memory (FRAM, ferromagnetic random access Memory), flash Memory (Flash Memory), magnetic surface Memory, optical disk, or compact disk Read Only Memory (CD-ROM, compact Disc Read-Only Memory); the magnetic surface memory may be a disk memory or a tape memory. The volatile memory may be random access memory (RAM, random Access Memory), which acts as external cache memory. By way of example, and not limitation, many forms of RAM are available, such as static random access memory (SRAM, static Random Access Memory), synchronous static random access memory (SSRAM, synchronous Static Random Access Memory), dynamic random access memory (DRAM, dynamic Random Access Memory), synchronous dynamic random access memory (SDRAM, synchronous Dynamic Random Access Memory), double data rate synchronous dynamic random access memory (ddr SDRAM, double Data Rate Synchronous Dynamic Random Access Memory), enhanced synchronous dynamic random access memory (ESDRAM, enhanced Synchronous Dynamic Random Access Memory), synchronous link dynamic random access memory (SLDRAM, syncLink Dynamic Random Access Memory), direct memory bus random access memory (DRRAM, direct Rambus Random Access Memory). The memory described by embodiments of the present application is intended to comprise, without being limited to, these and any other suitable types of memory.

In an exemplary embodiment, the present application also provides a storage medium, i.e. a computer storage medium, in particular a computer readable storage medium, for example comprising a memory 903 storing a computer program executable by the processor 902 of the electronic device 900 for performing the steps of the method described above. The computer readable storage medium may be FRAM, ROM, PROM, EPROM, EEPROM, flash Memory, magnetic surface Memory, optical disk, or CD-ROM.

It should be noted that: "first," "second," etc. are used to distinguish similar objects and not necessarily to describe a particular order or sequence.

In addition, the embodiments of the present application may be arbitrarily combined without any collision.

The foregoing description is only of the preferred embodiments of the present application, and is not intended to limit the scope of the present application.

Claims

1. A brake control method characterized by comprising:

2. The method of claim 1, wherein controlling the motor controller to switch between the first braking mode and the second braking mode by hysteresis control based on the bus voltage in combination with a first voltage threshold and a second voltage threshold comprises:

3. The method according to claim 1, wherein the method further comprises:

4. A method according to claim 3, wherein said determining a first current value comprises:

5. A method according to claim 3, wherein said determining a second current value comprises:

6. The method of claim 5, wherein determining the second current value using the fourth current value and a preset ramp instruction according to the comparison result comprises:

or,

7. A method according to claim 3, characterized in that the method further comprises:

8. The method according to claim 1, wherein the method further comprises:

9. The method according to any one of claims 1 to 8, further comprising:

10. The method of claim 9, wherein the determining whether braking of the target motor is required based on at least two of the first rotational speed, the second rotational speed, and the third rotational speed comprises:

11. The method of claim 9, wherein determining whether braking is required to be ended during braking of the target motor based on at least two of the first rotational speed, the second rotational speed, and the third rotational speed comprises:

12. A brake control apparatus, characterized by comprising:

13. An electronic device, comprising: a processor and a memory for storing a computer program capable of running on the processor,

wherein the processor is adapted to perform the steps of the method of any of claims 1 to 11 when the computer program is run.

14. A storage medium having stored thereon a computer program, which when executed by a processor performs the steps of the method according to any of claims 1 to 11.