WO2024078146A1 - 电机启动方法及电机启动电路 - Google Patents

电机启动方法及电机启动电路 Download PDF

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Publication number
WO2024078146A1
WO2024078146A1 PCT/CN2023/114363 CN2023114363W WO2024078146A1 WO 2024078146 A1 WO2024078146 A1 WO 2024078146A1 CN 2023114363 W CN2023114363 W CN 2023114363W WO 2024078146 A1 WO2024078146 A1 WO 2024078146A1
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WIPO (PCT)
Prior art keywords
open
angle
motor
increment
loop
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PCT/CN2023/114363
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English (en)
French (fr)
Inventor
华纯
赵旭东
李亚菲
华晶
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华润微集成电路(无锡)有限公司
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Publication of WO2024078146A1 publication Critical patent/WO2024078146A1/zh

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Classifications

    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02P—CONTROL OR REGULATION OF ELECTRIC MOTORS, ELECTRIC GENERATORS OR DYNAMO-ELECTRIC CONVERTERS; CONTROLLING TRANSFORMERS, REACTORS OR CHOKE COILS
    • H02P1/00—Arrangements for starting electric motors or dynamo-electric converters
    • H02P1/02—Details of starting control
    • H02P1/04—Means for controlling progress of starting sequence in dependence upon time or upon current, speed, or other motor parameter
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02P—CONTROL OR REGULATION OF ELECTRIC MOTORS, ELECTRIC GENERATORS OR DYNAMO-ELECTRIC CONVERTERS; CONTROLLING TRANSFORMERS, REACTORS OR CHOKE COILS
    • H02P1/00—Arrangements for starting electric motors or dynamo-electric converters
    • H02P1/16—Arrangements for starting electric motors or dynamo-electric converters for starting dynamo-electric motors or dynamo-electric converters
    • H02P1/46—Arrangements for starting electric motors or dynamo-electric converters for starting dynamo-electric motors or dynamo-electric converters for starting an individual synchronous motor
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02P—CONTROL OR REGULATION OF ELECTRIC MOTORS, ELECTRIC GENERATORS OR DYNAMO-ELECTRIC CONVERTERS; CONTROLLING TRANSFORMERS, REACTORS OR CHOKE COILS
    • H02P21/00—Arrangements or methods for the control of electric machines by vector control, e.g. by control of field orientation
    • H02P21/14—Estimation or adaptation of machine parameters, e.g. flux, current or voltage
    • H02P21/18—Estimation of position or speed
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02P—CONTROL OR REGULATION OF ELECTRIC MOTORS, ELECTRIC GENERATORS OR DYNAMO-ELECTRIC CONVERTERS; CONTROLLING TRANSFORMERS, REACTORS OR CHOKE COILS
    • H02P21/00—Arrangements or methods for the control of electric machines by vector control, e.g. by control of field orientation
    • H02P21/22—Current control, e.g. using a current control loop
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02P—CONTROL OR REGULATION OF ELECTRIC MOTORS, ELECTRIC GENERATORS OR DYNAMO-ELECTRIC CONVERTERS; CONTROLLING TRANSFORMERS, REACTORS OR CHOKE COILS
    • H02P21/00—Arrangements or methods for the control of electric machines by vector control, e.g. by control of field orientation
    • H02P21/34—Arrangements for starting

Definitions

  • the present invention relates to the field of motor control, and in particular to a motor starting method and a motor starting circuit.
  • FOC Field-Oriented Control
  • the motor startup process generally includes initial positioning, accelerated asynchronous drag, closed-loop control and other stages.
  • Initial positioning stage Generally, the rotor positioning is achieved by controlling the direct-axis reference current of the motor to gradually increase from zero to the positioning target current, and maintaining it for a period of time within the preset positioning stabilization time.
  • Acceleration asynchronous dragging stage control the direct-axis current of the motor to be controlled to gradually decrease, and the quadrature-axis reference current to gradually increase, and control the open-loop angle of the motor to be controlled to gradually increase from the positioning angle to the asynchronous dragging angle of the target start open-loop angle to participate in the magnetic field oriented control, and perform asynchronous drag on the motor.
  • Closed-loop stage When the asynchronous drag angle reaches the start open-loop angle, the motor operation is controlled by closed-loop control.
  • the acceleration curve of the asynchronous drag stage strongly depends on the program setting of the software personnel, and mainly relies on the software personnel's understanding of the motor characteristics to make real-time and reasonable planning, which makes the motor take a long time to reach the predetermined speed, the work efficiency is low, and it is difficult to meet the requirements of fast start-up and operation. Therefore, it is necessary to propose a new starting method to improve work efficiency and speed up the starting speed.
  • an object of the present invention is to provide a motor starting method and a motor starting circuit, which are used to solve the problems of slow starting speed and low efficiency of position sensorless motors in the prior art.
  • the present invention provides a motor starting method, which at least includes:
  • the motor is asynchronously driven, so that the open-loop angle is gradually increased to the target start-up open-loop angle, and the quadrature-axis reference current is gradually increased; wherein, during the asynchronous driving process, the open-loop angle increment gradually increases with time, thereby achieving smooth start-up;
  • ⁇ n is the open-loop angle of the current cycle
  • ⁇ n-1 is the open-loop angle of the previous cycle
  • ⁇ n is the open-loop angle increment of the current cycle
  • ⁇ n-1 is the open-loop angle increment of the previous cycle
  • ⁇ 2 ⁇ is the angle increment.
  • the angle plus increment of the open-loop angle in the i-th stage in step 2) satisfies:
  • the open-loop angle increment of each stage reaches the target angle increment of the corresponding stage, the angular velocity reaching standard interrupt signal is triggered, the angle increment and the quadrature-axis reference current increment are cleared; and the angle increment and the quadrature-axis reference current increment of the next stage are recalculated, or the open-loop angle increment and the quadrature-axis reference current of the current cycle are maintained.
  • the present invention further provides a motor starting circuit, which at least comprises:
  • Sampling module first coordinate conversion module, processor, reference current self-increment module, angle acceleration control module, proportional integral adjustment module, second coordinate conversion module, control signal generation module, drive module and motor;
  • the sampling module samples the current of the motor
  • the first coordinate conversion module is connected to the output ends of the sampling module and the angle acceleration control module, and performs coordinate conversion on the output signal of the sampling module to obtain the direct-axis current and the quadrature-axis current;
  • the processor provides a direct-axis reference current, a quadrature-axis reference current, a quadrature-axis reference current increment, an initial angle, an initial open-loop angle increment, and an angle increment;
  • the reference current self-increase module is connected to the output end of the processor, and obtains the quadrature-axis reference current of the current cycle based on the quadrature-axis reference current of the previous cycle and the quadrature-axis reference current increment;
  • the angle acceleration control module is connected to the output end of the processor, and adjusts the open-loop angle to the target start-up open-loop angle based on the initial angle, the initial open-loop angle increment and the angle increment; wherein the open-loop angle increment gradually increases with time;
  • the proportional-integral adjustment module is connected to the first coordinate conversion module, the processor and the output end of the reference current self-increment module, and performs proportional-integral adjustment operation based on the direct-axis current, the direct-axis reference current, the quadrature-axis current and the quadrature-axis reference current to obtain the direct-axis voltage and the quadrature-axis voltage;
  • the second coordinate conversion module is connected to the output ends of the angle acceleration control module and the proportional integral adjustment module, and performs coordinate conversion on the direct-axis voltage and the quadrature-axis voltage to obtain a three-phase voltage;
  • the control signal generating module generates a control signal of the motor based on the output signal of the second coordinate conversion module
  • the driving module is connected to the output end of the control signal generating module, generates a driving signal for the motor based on the control signal and drives the motor to start.
  • the angle acceleration control module includes an adding unit and a sine and cosine calculation unit;
  • the adding unit obtains the open-loop angle of the previous cycle, the open-loop angle increment of the previous cycle and the angle plus increment of the current cycle for addition operation to obtain the open-loop angle increment of the current cycle and the open-loop angle of the current cycle;
  • the sine and cosine calculation unit is connected to the output end of the addition unit, and performs sine and cosine calculation on the open-loop angle output by the addition unit.
  • the sine and cosine output by the sine and cosine calculation unit are used for motor startup control.
  • the angle acceleration control module further includes an upper limit control unit
  • the upper limit control unit is connected to the adding unit, and when the open-loop angle increment reaches the stage target angle increment, an angular velocity reaching interrupt signal is issued; when the open-loop angle increment is less than the target angle increment of the corresponding stage, the adding unit is controlled to perform addition operation based on the open-loop angle of the previous cycle and the open-loop angle increment of the current cycle to obtain the open-loop angle of the current cycle.
  • the adding unit includes a register and an adder
  • the register stores the open loop angle, the open loop angle increment and the angle increment
  • the adder is connected to the register to perform addition operation on the open-loop angle of the previous cycle, the open-loop angle increment of the previous cycle and the angle increment to obtain the open-loop angle increment of the current cycle and the open-loop angle of the current cycle.
  • the adding unit comprises a multiplexer, an adder and at least two registers;
  • Each register stores the open-loop angle, open-loop angle increment and angle increment of each motor
  • the multiplexer is connected to the output end of each register, selects one of the registers, and outputs the data in the selected register;
  • the adder is connected to the output end of the multiplexer, and performs addition operation on the open-loop angle of the previous cycle, the open-loop angle increment of the previous cycle and the angle increment at the output end of the multiplexer to obtain the open-loop angle increment of the current cycle and the open-loop angle of the current cycle.
  • the driving module includes a driving board that converts a low-voltage domain signal into a high-voltage domain signal to drive the motor to operate.
  • the motor is a permanent magnet synchronous motor without a position sensor.
  • the motor starting method and the motor starting circuit of the present invention have the following beneficial effects:
  • the motor starting method and the motor starting circuit of the present invention introduce an open-loop angle, an open-loop angle increment and an angle plus increment, so that the starting circuit is easier to implement in hardware. Only one adder needs to be repeatedly used to complete the starting process, which consumes less hardware resources in exchange for the release of CPU resources.
  • the motor starting method and the motor starting circuit of the present invention achieve smooth start-up by adjusting the open-loop angle increment, thereby reducing the "gear shifting" feeling of the motor rotation when switching the speed.
  • the motor starting method and the motor starting circuit of the present invention introduce an angle increment, which greatly speeds up the starting process and suppresses the probability of starting reversal within a certain range.
  • the motor starting method and the motor starting circuit of the present invention can be extended to any group of motors, and the starting of each motor reuses the same set of calculation logic, thereby reducing costs.
  • FIG. 1 is a schematic diagram showing waveforms of an open-loop angle increment and a quadrature-axis reference current during asynchronous driving of a segmented motor.
  • FIG. 2 is a waveform diagram showing the multiplication of angle and number of turns during a segmented asynchronous dragging process.
  • FIG. 3 is a schematic diagram showing a waveform of the electrical angle during a segmented asynchronous dragging process.
  • FIG. 4 is a schematic flow chart of a motor starting method according to the present invention.
  • FIG. 5 is a schematic diagram showing waveforms of angle increments in the motor starting method of the present invention.
  • FIG. 6 is a schematic diagram showing waveforms of an open-loop angle increment and a quadrature-axis reference current in the motor starting method of the present invention.
  • FIG. 7 is a schematic diagram showing a waveform of angle multiplied by number of turns in the motor starting method of the present invention.
  • FIG. 8 is a schematic diagram showing a waveform of an electrical angle in the motor starting method of the present invention.
  • FIG. 9 is a schematic diagram showing the principle of generating an angular velocity reaching standard interrupt signal in the motor starting method of the present invention.
  • FIG. 10 is a schematic diagram showing the structure of the motor starting circuit of the present invention.
  • FIG. 11 is a schematic diagram showing the structure of the angle acceleration control module of the present invention.
  • FIG. 12 is a schematic diagram showing a structure of an adding unit of the present invention.
  • FIG. 13 is another schematic diagram showing the structure of the adding unit of the present invention.
  • FIG. 14 is a schematic diagram showing the principle of adder multiplexing of the present invention.
  • Sampling Module 11 First coordinate transformation module 12
  • Processor 13 Reference current auto-increase module 14
  • Angle acceleration control module 141 Addition unit 1411, 1413a, 1413b, 1413c...1413n Registers 1412, 1415 Adder 1414 Multiplexer 142 Sin and Cosine Calculation Unit 143
  • Upper limit control unit 15 Proportional-integral regulation module 16
  • Second coordinate transformation module 17 Control signal generation module 18
  • Driver Module 19 Motor
  • the acceleration process of the motor is divided into several sections during the asynchronous drag stage to achieve stable acceleration and no loss of step of the motor during asynchronous drag.
  • the PWM drive frequency of the motor is 20Khz
  • the rated current of the motor is 2A
  • the open-loop start target speed of the motor is 20000 rpm
  • it is assumed that the initial positioning angle of the motor is just 0°.
  • the acceleration asynchronous drag stage is divided into 5 acceleration stages.
  • the horizontal axis is the sampling point (corresponding to the number of peaks or troughs of the PWM signal); wherein, in the five acceleration stages, the speed of each stage satisfies: the first speed ⁇ the second speed ⁇ the third speed ⁇ the fourth speed ⁇ the fifth speed (i.e., the target speed); the duration of each stage satisfies: the first duration Ta ⁇ the second duration Tb ⁇ the third duration Tc ⁇ the fourth duration Td ⁇ the fifth duration Te; the open-loop angle increment ⁇ remains unchanged in the same stage, and the open-loop angle increment ⁇ of each stage gradually increases with time; the quadrature axis reference current Iqref increases in an arithmetic progression at different stages with time.
  • another embodiment of the present invention proposes a motor starting method and a motor starting circuit, which overcomes the feeling of "shifting gears" during motor rotation through smooth starting, speeds up the starting process through angle increment, and can also release CPU resources.
  • the specific scheme of the motor starting method and the motor starting circuit of the embodiment is as follows.
  • this embodiment provides a motor starting method, and the motor starting method includes:
  • the motor in the initial state, the motor is in a stationary state, and the rotor position is unknown. At this time, the motor is The three-phase current of the motor is collected to obtain the current position of the rotor.
  • the direct axis reference current Id of the motor to be controlled is controlled to be the positioning target current, and the quadrature axis reference current Iq is zero, and is maintained for a period of time within a preset positioning stabilization time to achieve rotor positioning.
  • the motor is asynchronously dragged, so that the open-loop angle is gradually increased to the target starting open-loop angle, and the quadrature-axis reference current is gradually increased; wherein, during the asynchronous dragging process, the open-loop angle increment gradually increases with time, thereby achieving smooth starting.
  • ⁇ n is the open-loop angle of the current cycle
  • ⁇ n-1 is the open-loop angle of the previous cycle
  • ⁇ n is the open-loop angle increment of the current cycle
  • ⁇ n-1 is the open-loop angle increment of the previous cycle
  • ⁇ 2 ⁇ is the angle increment.
  • the open-loop angle increment increases as time goes by, wherein the angle increment ⁇ 2 ⁇ is greater than zero, and in actual use, the value of the angle increment ⁇ 2 ⁇ can be set as needed; the angle increment ⁇ 2 ⁇ at the same stage is a constant value, and in actual use, the angle increment ⁇ 2 ⁇ can also gradually increase, decrease, or change irregularly with the change of time, as long as the above formula is satisfied.
  • Iqref(n) is the quadrature-axis reference current of the motor in the current cycle
  • Iqref(n-1) is the quadrature-axis reference current of the motor in the previous cycle
  • ⁇ Iqref is the quadrature-axis reference current increment, and the specific value can be set as needed, which is not described here one by one.
  • the open-loop angle is adjusted in stages, and the angle increment ⁇ 2 ⁇ of the open-loop angle of each cycle in the same section is a constant value, and the angle increment ⁇ 2 ⁇ of the open-loop angle of each stage gradually increases with time; thereby, the startup process can be accelerated while achieving smooth startup.
  • the angle increment corresponding to each stage is calculated based on the driving frequency of the motor, the target speed of each stage, and the target angle increment of each stage.
  • the driving frequency of the motor is fixed at f Hz, that is, the motor has f PWM waveforms within 1 second;
  • the open-loop angle increment of the last PWM cycle within T i seconds is obtained, which is called the stage target angle increment ⁇ in .
  • the stage target angle increment ⁇ in satisfies the following formula:
  • the staged initial open-loop angle increment of the first stage can be set as needed, which is not described in detail here.
  • the open-loop angle is adjusted in three stages. Assuming that the motor drive frequency is 20K Hz, the rated current of the motor is 2 amperes, the open-loop start target speed of the motor is 20,000 rpm, and the initial asynchronous drag angle of the motor is the initial positioning angle (0° in the following example). As shown in Figure 5, the angle increment in the same stage is a constant value, and the angle increment in the first stage, the angle increment in the second stage, and the angle increment in the third stage increase in a step-like manner. As shown in Figure 6, the open-loop angle increments in the same stage all increase in an arithmetic progression.
  • the acceleration of each stage satisfies: the first acceleration ⁇ the second acceleration ⁇ the third acceleration; the quadrature axis reference current Iqref increases in an arithmetic progression; the duration of each stage satisfies: the first duration Ta ⁇ the second duration Tb ⁇ the third duration Tc.
  • the product curve of the angle ⁇ and the number of turns in each stage is smooth and has no turning point; as shown in FIG8 , the electrical angle of the accelerated asynchronous drag in each stage has no turning point at the switching point of each stage.
  • the number of segments of the segmented control can be set as needed, and is not limited to this embodiment.
  • the angular velocity standard-reaching interrupt signal is triggered, and the angle increment and the quadrature-axis reference current increment are cleared; and the angle increment and the quadrature-axis reference current increment of the next stage are recalculated, or the open-loop angle increment and the quadrature-axis reference current of the current cycle are maintained.
  • the open-loop angle increment of each stage reaches the target angle increment of the corresponding stage
  • the angular velocity standard-reaching interrupt signal is triggered, and the angle increment and the quadrature-axis reference current increment are cleared; and the angle increment and the quadrature-axis reference current increment of the next stage are recalculated, or the open-loop angle increment and the quadrature-axis reference current of the current cycle are maintained.
  • the time from 0 to T1 is the first stage, and when the open-loop angle increment of the first stage reaches the target angle increment of the first stage, the first angular velocity standard-reaching interrupt signal is triggered at time T1; the time from T1 to T2 is the second stage, and when the open-loop angle increment of the second stage reaches the target angle increment of the second stage, the second angular velocity standard-reaching interrupt signal is triggered at time T2.
  • Interrupt signal; T2-T3 is the third stage. When the open-loop angle increment of the third stage reaches the target angle increment of the third stage (which is also the target angle increment of the entire asynchronous dragging process), the third angular velocity standard-reaching interrupt signal is triggered at T3.
  • the open-loop angle increment is detected to determine whether the open-loop angle reaches the preset open-loop angle; in actual use, the open-loop angle can be directly detected. Any method that can determine the T1, T2, and T3 moments is applicable, and will not be described one by one here.
  • the back electromotive force is calculated using an observer method, and the estimated angle is obtained by taking the inverse tangent of the direct-axis and quadrature-axis back electromotive forces.
  • the difference between the open-loop operation angle and the estimated angle is within a certain range, it can be determined that the closed-loop condition is met and the motor enters the closed-loop mode.
  • any method that can make the motor enter closed-loop control is applicable to the present invention, and is not limited to this embodiment. It should be noted that for starting multiple motors, each motor can be started one by one based on the motor starting method of this embodiment, which is not described one by one here.
  • the present invention introduces the concept of angle plus increment ⁇ 2 ⁇ , so that the change curve of the asynchronous drag angle of the motor becomes smoother; through smooth starting, the "shifting" feeling of motor rotation is reduced, the starting process is accelerated, the motor starting time is shortened, the efficiency is improved, and the probability of starting reversal is reduced.
  • this embodiment provides a motor starting circuit, and the motor starting circuit includes:
  • the sampling module 10 The sampling module 10 , the first coordinate conversion module 11 , the processor 12 , the reference current self-increment module 13 , the angle acceleration control module 14 , the proportional integral adjustment module 15 , the second coordinate conversion module 16 , the control signal generation module 17 , the drive module 18 and the motor 19 .
  • the sampling module 10 samples the current of the motor 19 .
  • the sampling module 10 includes a sampling circuit connected to the motor 19 to sample the three-phase current (Iu, Iv, Iw) of the motor 19; in actual use, only two-phase currents may be sampled, and the third phase is obtained by calculation.
  • the first coordinate conversion module 11 is connected to the sampling module 10 and the angle acceleration control module At the output end of block 14 , coordinate transformation is performed on the output signal of the sampling module 10 to obtain the direct-axis current Id and the quadrature-axis current Iq.
  • the first coordinate conversion module 11 is a Clark transformation and/or a Park transformation
  • the three-phase current output by the sampling module 10 participates in the Clark/Park transformation of the magnetic field oriented control based on the sine and cosine values of the (n-1)th asynchronous drag angle ⁇ n-1 to obtain the direct-axis current Id and the quadrature-axis current Iq.
  • the processor 12 provides a direct-axis reference current I dref , a quadrature-axis reference current I qref , a quadrature-axis reference current increment ⁇ I qref at each stage, an initial angle ⁇ , an initial open-loop angle increment ⁇ , and an angle increment ⁇ 2 ⁇ at each stage.
  • the processor 12 is implemented by a central processing unit (CPU).
  • CPU central processing unit
  • any module that can realize data processing is applicable to the present invention, including but not limited to a microprocessor (MPU), an application specific integrated circuit (ASIC), a digital signal processor (DSP), a graphics processing unit (GPU), an image signal processor (ISP), or a field programmable gate array (FPGA).
  • MPU microprocessor
  • ASIC application specific integrated circuit
  • DSP digital signal processor
  • GPU graphics processing unit
  • ISP image signal processor
  • FPGA field programmable gate array
  • the reference current self-increase module 13 is connected to the output terminal of the processor 12 , and obtains the quadrature-axis reference current I qref( n) of the current cycle based on the quadrature-axis reference current I qref (n-1) of the previous cycle and the quadrature-axis reference current increment ⁇ I qref .
  • I qref(n) I qref(n-1) + ⁇ I qref .
  • the angle acceleration control module 14 is connected to the output end of the processor 2 , and adjusts the open-loop angle to the target start-up open-loop angle based on the initial angle ⁇ , the initial open-loop angle increment ⁇ and the angle increment ⁇ 2 ⁇ ; wherein the open-loop angle increment gradually increases with time.
  • the angle acceleration control module 14 includes an adding unit 141 and a sine-cosine calculation unit 142.
  • the adding unit 141 obtains the open-loop angle ⁇ n-1 of the previous cycle, the open-loop angle increment ⁇ n-1 of the previous cycle and the angle increment ⁇ 2 ⁇ of the current cycle for addition operation to obtain the open-loop angle increment ⁇ n of the current cycle and the open-loop angle ⁇ n of the current cycle; the adding unit 141 adds the open-loop angle increment ⁇ n-1 of the previous cycle to the angle increment ⁇ 2 ⁇ of the current cycle to obtain the open-loop angle increment ⁇ n of the current cycle, and the adding unit 141 also adds the open-loop angle increment ⁇ n of the current cycle to the open-loop angle ⁇ n-1 of the previous cycle to obtain the open-loop angle ⁇ n of the current cycle.
  • the sine and cosine calculation unit 142 is connected to the output end of the addition unit 141, and performs sine and cosine calculations on the open-loop angle ⁇ n output by the addition unit 141.
  • the sine and cosine output by the sine and cosine calculation unit 142 are used for motor start control.
  • the adder for calculating the open-loop angle increment ⁇ n of the current cycle and the open-loop angle ⁇ n of the current cycle in the adding unit 141 is the same, which is implemented by time-division multiplexing; in actual use, multiple adders can be set as needed to respectively implement the calculation of the open-loop angle increment ⁇ n of the current cycle and the open-loop angle ⁇ n of the current cycle.
  • the adding unit 141 includes a register 1411 and an adder 1412.
  • the register 1411 stores the open-loop angle, the open-loop angle increment and the angle increment of each cycle.
  • the adder 1412 is connected to the register 1411, and performs addition operation on the open-loop angle ⁇ n-1 of the previous cycle, the open-loop angle increment ⁇ n-1 of the previous cycle and the angle increment ⁇ 2 ⁇ to obtain the open-loop angle ⁇ n of the current cycle.
  • the adding unit 141 includes at least two registers (in this example, set to 1413a, 1413b, 1413c ... 1413n), a multiplexer 1414 and an adder 1415. Each register stores the open-loop angle, open-loop angle increment and angle increment of each motor, that is, each register corresponds to a motor.
  • the multiplexer 1414 is connected to the output end of each register, selects one of the registers, and outputs the data in the selected register; the multiplexer 1414 can be selected one by one in channel order according to the selection control signal, or the selection order can be set as needed according to the selection control signal, which is not described one by one here.
  • the adder 1415 is connected to the output end of the multiplexer 1414, and performs addition operation on the open-loop angle of the previous cycle, the open-loop angle increment of the previous cycle and the angle increment of the output end of the multiplexer 1414 to obtain the open-loop angle of the current cycle of the corresponding motor.
  • the adder 1415 is multiplexed with multiple motors, which can effectively reduce costs.
  • angle acceleration control module 14 is described in the first embodiment and will not be elaborated here.
  • the proportional-integral adjustment module 15 is connected to the first coordinate conversion module 11 , the processor 12 and the output end of the reference current self-increase module 13 , and is based on the direct-axis current I d , the direct-axis reference current I dref , and the quadrature-axis current I q And the quadrature-axis reference current Iqref are used for proportional-integral regulation to obtain the direct-axis voltage Ud and the quadrature-axis voltage Uq .
  • the proportional-integral adjustment module 15 includes an integrator circuit; in practical applications, any structure that can implement proportional-integral operation is applicable to the proportional-integral adjustment module 15 of the present invention, which will not be described in detail here.
  • the direct-axis current I d and the direct-axis reference current I dref are used to participate in the proportional-integral adjustment operation of the magnetic field oriented control to obtain the direct-axis voltage U d ;
  • the quadrature-axis current I q and the quadrature-axis reference current I qref are used to participate in the proportional-integral adjustment operation of the magnetic field oriented control to obtain the quadrature-axis voltage U q .
  • the control signal generating module generates a control signal of the motor based on the output signal of the second coordinate conversion module
  • the driving module is connected to the output end of the control signal generating module, generates a driving signal for the motor based on the control signal and drives the motor to start.
  • the second coordinate conversion module 16 is connected to the output ends of the angle acceleration control module 14 and the proportional integral adjustment module 15 , and performs coordinate conversion on the direct-axis voltage U d and the quadrature-axis voltage U q to obtain a three-phase voltage.
  • the second coordinate conversion module 16 is a Clark inverse transformation and/or a Park inverse transformation, and the direct-axis voltage Ud and the quadrature-axis voltage Uq participate in the Clark/Park inverse transformation of the magnetic field oriented control through the sine and cosine values of the nth asynchronous drag angle ⁇ n to obtain the three-phase voltage (Uu, Uv, Uw).
  • control signal generating module 17 generates a control signal for the motor 19 based on the output signal of the second coordinate conversion module 16 .
  • control signal generating module 17 generates a SVPWM signal.
  • the driving module 18 is connected to the output end of the control signal generating module 17 , generates a driving signal for the motor 19 based on the control signal, and drives the motor 19 to start.
  • the driving module 18 includes a driving board (e.g., a motor driver circuit board) that converts a low-voltage domain signal into a high-voltage domain signal to drive the motor 19 to operate.
  • a driving board e.g., a motor driver circuit board
  • any circuit structure that can drive the motor to operate based on the motor control signal is applicable to the present invention, and is not limited to this embodiment.
  • the number of the drive modules 18 needs to be consistent with the number of the motors 19 .
  • the motor 19 is connected to the output end of the driving module 18 and is driven by the driving module 18 to work.
  • the motor 19 is a permanent magnet synchronous motor without a position sensor.
  • any motor without a position sensor or with a position sensor is applicable, and is not limited to this embodiment.
  • the present invention retains the startup information of multiple channels in the angle acceleration control module (including but not limited to open-loop angle, open-loop Angle increment, angle plus increment), the processor can access the same set of registers to achieve parameter access and motor start for any channel of the motor. Time-division multiplexing is used to select only one channel of information at the same time to start the motor. After the calculation is completed, the next channel of information is selected to start the next motor. The calculation process of multiple channels does not require the participation of the processor. Only when the calculation is completed will the processor be notified to adjust the angle plus increment ⁇ 2 ⁇ and the quadrature axis reference current increment, which greatly reduces the burden on the processor and can be easily expanded to any channel.
  • the present invention is easier to implement in hardware by setting the angle ⁇ , the open-loop angle increment ⁇ and the angle plus increment ⁇ 2 ⁇ .
  • the startup process can be completed by repeatedly using an adder and a limiter. A small amount of hardware resources are spent in exchange for the release of CPU resources, which shortens the time for software personnel to plan the acceleration curve so that the motor can start more smoothly.
  • the smooth start is used to reduce the "shifting" feeling of the motor rotation when the speed is switched.
  • the concept of angle plus increment is added, the startup process is accelerated, the motor startup time is shortened, the success rate of the motor startup is improved, and the probability of startup reversal is reduced within a certain range.
  • the present invention provides a motor starting method and a motor starting circuit, including: 1) obtaining the current position of the rotor; 2) asynchronously dragging the motor based on the current position of the rotor and the rotation direction of the motor, so that the open-loop angle gradually increases to the target start-up open-loop angle, and the quadrature axis reference current gradually increases; wherein, during the asynchronous dragging process, the open-loop angle increment gradually increases with time, thereby achieving smooth start-up; 3) the motor enters a closed-loop control mode.
  • the motor starting method and the motor starting circuit of the present invention introduce an open-loop angle, an open-loop angle increment, and an angle plus increment, so that the start-up circuit is easier to implement in hardware, and only one adder is needed to repeatedly use to complete the start-up process, which consumes less hardware resources in exchange for the release of CPU resources; by adjusting the open-loop angle increment to achieve smooth start-up, the "shifting" feeling of the motor rotation is reduced when the rate is switched; the angle plus increment is introduced to greatly speed up the start-up process and suppress the probability of start-up reversal within a certain range; it can be extended to any group of motors, and the start-up of each motor reuses the same group of calculation logic to reduce costs. Therefore, the present invention effectively overcomes the various shortcomings of the prior art and has a high industrial utilization value.

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Abstract

本发明提供一种电机启动方法及电机启动电路。所述电机启动方法包括：1)获取转子的当前位置；2)基于转子的当前位置及电机的转动方向对电机进行异步拖动，使开环角度逐步增大至目标启动开环角度，交轴参考电流逐步增大；在异步拖动的过程中开环角度增量随时间的变化逐步增大，进而实现平滑启动；3)电机进入闭环控制模式。本发明引入开环角度，开环角度增量以及角度加增量，使得启动电路更易于硬件实现，只需一个加法器即可完成启动，花费硬件资源少，换取CPU资源的释放；通过调整开环角度增量实现平滑开启，减轻电机转动的"换挡"感觉；引入角度加增量加快启动进程，抑制启动反转的概率；可扩展至任意组电机，且各电机的启动复用一组计算逻辑，成本低。

Description

电机启动方法及电机启动电路 技术领域
本发明涉及电机控制领域，特别是涉及一种电机启动方法及电机启动电路。
背景技术
无位置传感器电机因价格便宜，可靠性高，被广泛应用于电机控制领域。目前在通过无感控制电机运行的控制技术中，磁场定向控制(Field-Oriented Control，FOC)是一种对于无刷直流电机和永磁同步电机都可以实现精确控制的高效控制技术。在通过FOC控制电机运行的过程中，电机的启动过程一般包括初始定位、加速异步拖动、闭环控制等阶段。
初始定位阶段：一般通过控制电机的直轴参考电流从零开始逐步增加至定位目标电流，并在预设的定位稳定时间内维持一段时间，实现转子定位。
加速异步拖动阶段：控制待控制电机的直轴电流逐渐减小，交轴参考电流逐渐增大，并控制待控制电机的开环角度的从定位角度逐步增加至所述目标启动开环角度的异步拖动角度参与磁场定向控制，对所述电机进行异步拖动。
闭环阶段：当异步拖动角度达到所述启动开环角度后，通过闭环控制的方式控制所述电机运行。
其中，加速异步拖动阶段的加速曲线强烈依赖软件人员的程序设定，主要靠软件人员对电机特性的了解而实时合理规划，使得电机达到预定转速的时间长，工作效率低下，很难满足快速启动运行的要求。因此，有必要提出一种新的启动方法，以提高工作效率、加快启动速度。
应该注意，上面对技术背景的介绍只是为了方便对本申请的技术方案进行清楚、完整的说明，并方便本领域技术人员的理解而阐述的。不能仅仅因为这些方案在本申请的背景技术部分进行了阐述而认为上述技术方案为本领域技术人员所公知。
发明内容
鉴于以上所述现有技术的缺点，本发明的目的在于提供一种电机启动方法及电机启动电路，用于解决现有技术中无位置传感器电机启动速度慢，效率低等问题。
为实现上述目的及其他相关目的，本发明提供一种电机启动方法，所述电机启动方法至少包括：
1)获取转子的当前位置；
2)基于所述转子的当前位置及电机的转动方向对所述电机进行异步拖动，使开环角度逐步增大至目标启动开环角度，交轴参考电流逐步增大；其中，在异步拖动的过程中开环角度增量随时间的变化逐步增大，进而实现平滑启动；
3)所述电机进入闭环控制模式。
可选地，所述开环角度满足：
θn＝θn-1+Δθn，Δθn＝Δθn-1+Δ2θ；
其中，θn为当前周期的所述开环角度，θn-1为上一周期的所述开环角度，Δθn为当前周期的开环角度增量，Δθn-1为上一周期的开环角度增量，Δ2θ为角度加增量。
更可选地，步骤2)中分阶段调整所述开环角度，同一阶段内各周期的所述开环角度的角度加增量为恒定值，各阶段的所述开环角度的角度加增量随时间的变化逐步增大。
更可选地，步骤2)中第i阶段所述开环角度的角度加增量满足：

其中，Δ2θi为第i阶段所述开环角度的角度加增量，i为大于等于1的自然数；Δθin为第i阶段最后一个周期的目标角度增量；Δθi0为第i阶段第一个周期的开环角度增量；Ti为第i阶段的时长(作为示例，单位为秒)；f为电机驱动频率(作为示例，单位为赫兹)；N为第i阶段的目标转速(作为示例，单位为转/秒)；p为电机的极对数；当i≥2时，Δθi0＝Δθ(i-1)n，Δθ(i-1)n为第(i-1)阶段最后一个周期的目标角度增量。
更可选地，当各阶段的开环角度增量达到对应阶段的目标角度增量时，触发角速度达标中断信号，清除角度加增量及交轴参考电流增量；并重新计算下一阶段的角度加增量及交轴参考电流增量，或维持当前周期的开环角度增量及交轴参考电流。
为实现上述目的及其他相关目的，本发明还提供一种电机启动电路，所述电机启动电路至少包括：
采样模块、第一坐标转换模块、处理器、参考电流自增模块、角度加速控制模块、比例积分调节模块、第二坐标转换模块、控制信号产生模块、驱动模块及电机；
所述采样模块对所述电机的电流进行采样；
所述第一坐标转换模块连接于所述采样模块及所述角度加速控制模块的输出端，对所述采样模块的输出信号进行坐标转换，得到直轴电流和交轴电流；
所述处理器提供直轴参考电流、交轴参考电流、交轴参考电流增量、初始角度、初始开环角度增量及角度加增量；
所述参考电流自增模块连接于所述处理器的输出端，基于上一周期的交轴参考电流及所述交轴参考电流增量得到当前周期的交轴参考电流；
所述角度加速控制模块连接于所述处理器的输出端，基于所述初始角度、所述初始开环角度增量及所述角度加增量将开环角度调整至目标启动开环角度；其中，开环角度增量随时间的变化逐步增大；
所述比例积分调节模块连接于所述第一坐标转换模块、所述处理器及所述参考电流自增模块的输出端，基于直轴电流、直轴参考电流、交轴电流及交轴参考电流进行比例积分调节运算，得到直轴电压和交轴电压；
所述第二坐标转换模块连接于所述角度加速控制模块及所述比例积分调节模块的输出端，对所述直轴电压和所述交轴电压进行坐标转换，得到三相电压；
所述控制信号产生模块基于所述第二坐标转换模块的输出信号产生所述电机的控制信号；
所述驱动模块连接于所述控制信号产生模块的输出端，基于所述控制信号产生所述电机的驱动信号并驱动所述电机启动。
可选地，所述角度加速控制模块包括加法单元及正余弦计算单元；
所述加法单元获取上一周期的开环角度、上一周期的开环角度增量及当前周期角度加增量进行加法运算，以得到当前周期的开环角度增量及当前周期的开环角度；
所述正余弦计算单元连接于所述加法单元的输出端，对所述加法单元输出的开环角度进行正弦和余弦计算，所述正余弦计算单元输出的正弦和余弦用于电机启动控制。
更可选地，所述角度加速控制模块还包括上限控制单元；
所述上限控制单元连接所述加法单元，当开环角度增量达到阶段性目标角度增量时，发出角速度达标中断信号；当开环角度增量小于对应阶段的目标角度增量时，控制所述加法单元基于上一周期的开环角度与当前周期的开环角度增量进行加法运算，得到当前周期的开环角度。
更可选地，所述加法单元包括寄存器及加法器；
所述寄存器中存储开环角度、开环角度增量及角度加增量；
所述加法器连接所述寄存器，对上一周期的开环角度、上一周期的开环角度增量及角度加增量进行加法运算，以得到当前周期的开环角度增量及当前周期的开环角度。
更可选地，所述加法单元包括多路复用器、加法器及至少两个寄存器；
各寄存器中分别存储各电机的开环角度、开环角度增量及角度加增量；
所述多路复用器连接于各寄存器的输出端，选择各寄存器中的一个，并输出被选中寄存器中的数据；
所述加法器连接所述多路复用器的输出端，对所述多路复用器输出端的上一周期的开环角度、上一周期的开环角度增量及角度加增量进行加法运算，以得到当前周期的开环角度增量及当前周期的开环角度。
可选地，所述驱动模块包括驱动板，将低压域信号转变为高压域信号，以驱动电机运转。
可选地，所述电机为无位置传感器的永磁同步电机。
如上所述，本发明的电机启动方法及电机启动电路，具有以下有益效果：
1、本发明的电机启动方法及电机启动电路引入开环角度，开环角度增量以及角度加增量，使得启动电路更易于硬件实现，只需要一个加法器的重复使用，就可以完成启动过程，花费硬件资源少，换取CPU资源的释放。
2、本发明的电机启动方法及电机启动电路通过调整开环角度增量实现平滑开启，在进行速率切换时减轻电机转动的“换挡”感觉。
3、本发明的电机启动方法及电机启动电路引入角度加增量，大大加快启动进程，在一定范围内抑制启动反转的概率。
4、本发明的电机启动方法及电机启动电路可扩展至任意组电机，且各电机的启动复用同一组计算逻辑，降低成本。
附图说明
图1显示为一种分段式电机异步拖动过程中开环角度增量和交轴参考电流的波形示意图。
图2显示为一种分段式异步拖动过程中角度乘圈数的波形示意图。
图3显示为一种分段式异步拖动过程中电角度的波形示意图。
图4显示为本发明的电机启动方法的流程示意图。
图5显示为本发明的电机启动方法中角度加增量的波形示意图。
图6显示为本发明的电机启动方法中开环角度增量和交轴参考电流的波形示意图。
图7显示为本发明的电机启动方法中角度乘圈数的波形示意图。
图8显示为本发明的电机启动方法中电角度的波形示意图。
图9显示为本发明的电机启动方法中角速度达标中断信号的产生原理示意图。
图10显示为本发明的电机启动电路的结构示意图。
图11显示为本发明的角度加速控制模块的结构示意图。
图12显示为本发明的加法单元的一种结构示意图。
图13显示为本发明的加法单元的另一种结构示意图。
图14显示为本发明的加法器复用的原理示意图。
元件标号说明
10                               采样模块
11                               第一坐标转换模块
12                               处理器
13                               参考电流自增模块
14                               角度加速控制模块
141                              加法单元
1411、1413a、1413b、1413c…1413n 寄存器
1412、1415                       加法器
1414                             多路复用器
142                              正余弦计算单元
143                              上限控制单元
15                               比例积分调节模块
16                               第二坐标转换模块
17                               控制信号产生模块
18                               驱动模块
19                               电机
具体实施方式
以下通过特定的具体实例说明本发明的实施方式，本领域技术人员可由本说明书所揭露的内容轻易地了解本发明的其他优点与功效。本发明还可以通过另外不同的具体实施方式加以实施或应用，本说明书中的各项细节也可以基于不同观点与应用，在没有背离本发明的精神下进行各种修饰或改变。
请参阅图1～图14。需要说明的是，本实施例中所提供的图示仅以示意方式说明本发明的基本构想，遂图式中仅显示与本发明中有关的组件而非按照实际实施时的组件数目、形状及尺寸绘制，其实际实施时各组件的型态、数量及比例可为一种随意的改变，且其组件布局型 态也可能更为复杂。
如图1～图3所示，在本案一个实施例中，为了缩小电机启动时间，加快电机启动速度，在异步拖动阶段将电机的加速过程分成若干段，以达到异步拖动期间电机的稳定加速和不失步。作为示例，电机的PWM驱动频率为20Khz，电机的额定电流为2A，电机的开环启动目标速度为20000转/分，假设电机的初始定位角度刚好为0°，为了电机的稳步启动，将加速异步拖动阶段分为5个加速阶段。如图1所示，横坐标为采样点(对应PWM信号的波峰或波谷的个数)；其中，五个加速阶段中，各阶段的转速满足：第一转速<第二转速<第三转速<第四转速<第五转速(即目标转速)；各阶段的持续时间满足：第一持续时间Ta<第二持续时间Tb<第三持续时间Tc<第四持续时间Td<第五持续时间Te；开环角度增量Δθ在同一阶段保持不变，随着时间的变化各阶段的开环角度增量Δθ逐步增大；随着时间的变化交轴参考电流Iqref在不同阶段均呈等差数列递增。根据以上不同阶段的电机异步拖动角度和交轴参考电流参与磁场定向控制的比例积分，Clark/Park及其逆变换，对电机进行异步拖动。如图2所示，各阶段的角度θ与圈数的乘积的曲线存在转折点；如图3所示，各阶段的加速异步拖动的电角度在各阶段的切换点存在转折点。
如图1所示，以上过程中，在电机从所述第一转速跃入所述第二转速、所述第二转速跃入所述第三转速、所述第三转速跃入所述第四转速、所述第四转速跃入所述第五转速(目标转速)时，电机转速呈阶梯跳跃，使得电机的加速曲线不够平滑，电机在转动过程中有明显的“换档”感觉，严重的更能导致电机发生启动失败。
此外，以上过程中异步拖动的角度及参考电流的调整通常使用CPU来实现，CPU需要在每个电机的PWM周期都来检测电压和开环角度是否到达阶段性阈值，占用较多的CPU资源。特别是由单通道电机扩展到多通道电机的场景时，这种CPU控制启动电路的方式会显现出更多的劣势。
由此，为了优化上述实施例，本发明另一实施例提出一种电机启动方法和电机启动电路，其通过平滑启动克服电机转动中“换档”的感觉，并通过角度加增量加快启动进程；还能释放CPU资源。所述实施例的电机启动方法和电机启动电路的具体方案如下。
实施例一
如图4所示，本实施例提供一种电机启动方法，所述电机启动方法包括：
1)获取转子的当前位置。
具体地，起始状态下，电机处于静止状态，且所述转子位置未知，此时，对所述电机通 电并采集所述电机的三相电流，以此获取所述转子的当前位置。作为示例，控制待控制电机的直轴参考电流Id为定位目标电流，交轴参考电流Iq为零，并在预设的定位稳定时间内维持一段时间，实现转子定位。
需要说明的是，任意能获取所述转子的当前位置的方法均适用于本发明，不以本实施例为限。
2)基于所述转子的当前位置及电机的转动方向对所述电机进行异步拖动，使开环角度逐步增大至目标启动开环角度，交轴参考电流逐步增大；其中，在异步拖动的过程中开环角度增量随时间的变化逐步增大，进而实现平滑启动。
具体地，本发明中引入开环角度、开环角度增量及角度加增量(角度加增量用于描述开环角度增量变化的速度，即开环角度变化的加速度)，所述开环角度满足：
θn＝θn-1+Δθn，Δθn＝Δθn-1+Δ2θ；
其中，θn为当前周期的所述开环角度，θn-1为上一周期的所述开环角度，Δθn为当前周期的开环角度增量，Δθn-1为上一周期的开环角度增量，Δ2θ为角度加增量。也就是说，随着时间越往后开环角度增量越大，其中，角度加增量Δ2θ大于零，在实际使用中可根据需要设定所述角度加增量Δ2θ的数值；同一阶段的所述角度加增量Δ2θ为恒定值，在实际使用中所述角度加增量Δ2θ也可随着时间的变化逐步增大、减小或无规则变化，能满足上式即可。
具体地，本发明中电机交轴参考电流满足：
Iqref(n)＝Iqref(n-1)+ΔIqref；
其中，Iqref(n)为当前周期的电机交轴参考电流；Iqref(n-1)为上一周期的电机交轴参考电流；ΔIqref为交轴参考电流增量，可根据需要设定具体数值，在此不一一赘述。
更具体地，在本实施例中，分阶段调整所述开环角度，同一段内各周期的所述开环角度的角度加增量Δ2θ为恒定值，各阶段的所述开环角度的角度加增量Δ2θ随时间的变化逐步增大；以此可在实现平滑启动的同时加快启动进程。进一步地，本实施例中，基于电机的驱动频率、各阶段的目标转速、各阶段的目标角度增量计算各阶段对应的角度加增量。假设电机的驱动频率固定为f赫兹，也就是电机在1秒内的PWM波形出现了f个；第i阶段的阶段性目标为Ti秒内转速增加至N转/秒；其中已知阶段性初始开环角度增量初值为Δθi0，电机的极对数为p；其中i≥1，i为自然数，当i＝1时则为一段式加速过程，一段式加速过程并不会影响电机启动的平滑性，并且一段式加速过程更能缩小电机启动的时间。由以上条件可计算 得到Ti秒内最后一个PWM周期的开环角度增量，在此称为阶段性目标角度增量Δθin，当电机运行的开环角度增量在该离散点达到Δθin时，此时电机在该点时的转速为N转/秒。阶段性目标角度增量Δθin满足如下公式：
由于各阶段的开环角度增量Δθ呈现出的等差数列性质，可得到第i阶段的阶段性角度加增量Δ2θi满足：
当i≥2时，其中第i阶段的阶段性初始开环角度增量与第(i-1)阶段的阶段性目标角度增量相等，也就是：Δθi0＝Δθ(i-1)n。当i＝1时，第1阶段的阶段性初始开环角度增量可根据需要设置，在此不一一赘述。
如图5～图7所示，作为示例，分三阶段对所述开环角度进行调整，假设电机驱动频率为20K赫兹，电机的额定电流为2安培，电机的开环启动目标速度为20000转/分，电机的初始异步拖动角度为初始定位角度(以下例子中为0°)。如图5所示，同一阶段的角度加增量为恒定值，第一阶段的角度加增量、第二阶段的角度加增量及第三阶段的角度加增量呈阶梯状递增。如图6所示，同一阶段的开环角度增量均呈等差数列递增。各阶段加速度满足：第一加速度<第二加速度<第三加速度；交轴参考电流Iqref均呈等差数列递增；各阶段的持续时间满足：第一持续时间Ta<第二持续时间Tb<第三持续时间Tc。根据以上不同阶段的电机异步拖动角度和交轴参考电流参与磁场定向控制的比例积分，Clark/Park及其逆变换，对所述电机进行异步拖动。如图7所示，各阶段的角度θ与圈数的乘积曲线平滑，不存在转折点；如图8所示，各阶段的加速异步拖动的电角度在各阶段的切换点处不存在转折点。需要说明的是，在实际使用中，可根据需要设定分段控制的段数，不以本实施例为限。
具体地，作为本发明的一种实现方式，当各阶段的开环角度增量达到对应阶段的目标角度增量时，触发角速度达标中断信号，清除角度加增量及交轴参考电流增量；并重新计算下一阶段的角度加增量及交轴参考电流增量，或维持当前周期的开环角度增量及交轴参考电流。在本实施例中，如图9所示，0～T1时刻为第一阶段，当第一阶段的开环角度增量达到第一阶段的目标角度增量时，在T1时刻触发第一角速度达标中断信号；T1～T2时刻为第二阶段，当第二阶段的开环角度增量达到第二阶段的目标角度增量时，在T2时刻触发第二角速度达标中 断信号；T2～T3时刻为第三阶段，当第三阶段的开环角度增量达到第三阶段的目标角度增量(也是整个异步拖动过程的目标角度增量)时，在T3时刻触发第三角速度达标中断信号。当开环角度增量达到阶段性目标角度增量值时，角度加速控制器发出角速度达标中断，并清除角度加增量(Δ2θ＝0)和交轴参考电流增量(ΔIqref＝0)，可根据角速度达标中断信号得知某一阶段性平滑加速已完成，并根据电机运转的具体情况，配置新的角度加增量Δ2θ和交轴参考电流增量ΔIqref，让电机进入下一个阶段性平滑加速；或是不再配置新的角度加增量，即Δ2θ＝0，和交轴参考电流增量，即ΔIqref＝0，让电机进入稳定运行环节，进而进入电机闭环控制。
需要说明的是，在本示例中，通过检测所述开环角度增量确定开环角度是否达到预设开环角度；在实际使用中可直接对开环角度进行检测。任意能确定T1、T2、T3时刻的方式均适用，在此不一一赘述。
3)所述电机进入闭环控制模式。
具体地，在本实施例中，所述电机加速到目标转速后，采用观测器方式计算反电动势，通过求直轴和交轴反电动势的反正切得出估测角度，当开环运行角度与估测角度差异在一定范围内时，可判定闭环条件成立，所述电机进入闭环模式。
需要说明的是，任意能使电机进入闭环控制的方法均适用于本发明，不以本实施例为限。需要说明的是，对于多电机的启动，可基于本实施例的电机启动方法逐一对各电机进行启动，在此不一一赘述。
本发明引入角度加增量的概念Δ2θ，使得电机的异步拖动角度的变化曲线变得更加平缓；通过平滑启动减轻电机转动的“换挡”感，并加快启动进程，缩短电机启动时间，提高效率，同时减小启动反转的几率。
实施例二
如图10所示，本实施例提供一种电机启动电路，所述电机启动电路包括：
采样模块10、第一坐标转换模块11、处理器12、参考电流自增模块13、角度加速控制模块14、比例积分调节模块15、第二坐标转换模块16、控制信号产生模块17、驱动模块18及电机19。
如图10所示，所述采样模块10对所述电机19的电流进行采样。
具体地，所述采样模块10包含一采样电路，连接所述电机19，对所述电机19的三相电流(Iu、Iv、Iw)进行采样；实际使用中，可仅采两相电流，第三相通过计算得到。
如图10所示，所述第一坐标转换模块11连接于所述采样模块10及所述角度加速控制模 块14的输出端，对所述采样模块10的输出信号进行坐标转换，得到直轴电流Id和交轴电流Iq。
具体地，在本实施例中，所述第一坐标转换模块11为Clark变换和/或Park变换，所述采样模块10输出的三相电流基于第(n-1)次异步拖动角度θn-1的正余弦值参与磁场定向控制的Clark/Park变换，得到所述直轴电流Id及所述交轴电流Iq。
如图10所示，所述处理器12提供直轴参考电流Idref、交轴参考电流Iqref、各阶段的交轴参考电流增量ΔIqref、初始角度θ、初始开环角度增量Δθ及各阶段的角度加增量Δ2θ。
具体地，在本实施例中，所述处理器12采用中央处理器(Central Processing Unit，CPU)实现，在实际使用中，任意能实现对数据处理的模块均适用于本发明，包括但不限于微处理器(MPU)，应用特定集成电路(ASIC)，数字信号处理器(DSP)，图像处理器(GPU)，图像信号处理器(ISP)，或现场可编程门阵列(FPGA)等。各阶段的角度加增量Δ2θ基于实施例一中的计算方法计算得到，在此不一一赘述。
如图10所示，所述参考电流自增模块13连接于所述处理器12的输出端，基于上一周期的交轴参考电流Iqref(n-1)及所述交轴参考电流增量ΔIqref得到当前周期的交轴参考电流Iqref(n)。
具体地，满足如下关系式：Iqref(n)＝Iqref(n-1)+ΔIqref。
如图10所示，所述角度加速控制模块14连接于所述处理器2的输出端，基于所述初始角度θ、所述初始开环角度增量Δθ及所述角度加增量Δ2θ将开环角度调整至目标启动开环角度；其中，开环角度增量随时间的变化逐步增大。
具体地，如图11所示，所述角度加速控制模块14包括加法单元141及正余弦计算单元142。所述加法单元141获取上一周期的开环角度θn-1、上一周期的开环角度增量Δθn-1及当前周期角度加增量Δ2θ进行加法运算，以得到当前周期的开环角度增量Δθn及当前周期的开环角度θn；所述加法单元141将上一周期的开环角度增量Δθn-1与当前周期角度加增量Δ2θ相加，以得到当前周期的开环角度增量Δθn，所述加法单元141还将当前周期的开环角度增量Δθn与上一周期的开环角度θn-1相加，以得到当前周期的开环角度θn。所述正余弦计算单元142连接于所述加法单元141的输出端，对所述加法单元141输出的开环角度θn进行正弦和余弦计算，所述正余弦计算单元142输出的正弦和余弦用于电机启动控制。作为本发明的另一种实现方式，为了进一步获取处理器资源的释放，所述角度加速控制模块14还包括上限控制单元143；所述上限控制单元143连接所述加法单元141，当当前周期的开环角度增量Δθn达到阶段性目标角度增量时，发出角速度达标中断信号Achieve_INT，清除角度加增量(Δ2θ＝0) 和交轴参考电流增量(ΔIqref＝0)，并通知所述处理器12更新下一阶段的角度加增量Δ2θ及交轴参考电流增量ΔIqref或不再配置新的角度加增量(Δ2θ＝0)和交轴参考电流增量(ΔIqref＝0)，让电机进入稳定运行环节，进而进入电机闭环控制阶段；当当前周期的开环角度增量Δθn小于对应阶段的目标角度增量时，控制所述加法单元141基于上一周期的开环角度θn-1与当前周期的开环角度增量Δθn进行加法运算，得到当前周期的开环角度θn。图11中Δθ为开环角度增量的中间量，经过所述上限控制单元143得到的Δθn才是实际的开环角度增量(第一级加法器的输出值或0)。
更具体地，在本实施例中，所述加法单元141中计算当前周期的开环角度增量Δθn及当前周期的开环角度θn的加法器为同一个，通过分时复用实现；在实际使用中，可根据需要设置多个加法器分别实现当前周期的开环角度增量Δθn与当前周期的开环角度θn的计算。作为一种示例，如图12所示，对于单电机启动的应用，所述加法单元141包括寄存器1411及加法器1412。所述寄存器1411中存储各个周期的开环角度、开环角度增量及角度加增量。所述加法器1412连接所述寄存器1411，对上一周期的开环角度θn-1、上一周期的开环角度增量Δθn-1及角度加增量Δ2θ进行加法运算，以得到当前周期的开环角度θn。作为另一种示例，如图13所示，对于多电机启动的应用，所述加法单元141包括至少两个寄存器(在本示例中，设置为1413a、1413b、1413c……1413n)、多路复用器1414及加法器1415。各寄存器中分别存储各电机的开环角度、开环角度增量及角度加增量，即每个寄存器对应一个电机。所述多路复用器1414连接于各寄存器的输出端，选择各寄存器中的一个，并输出被选中寄存器中的数据；所述多路复用器1414可根据选择控制信号按通道顺序逐一选通，也可根据选择控制信号按需要设定选通顺序，在此不一一赘述。所述加法器1415连接所述多路复用器1414的输出端，对所述多路复用器1414输出端的上一周期的开环角度、上一周期的开环角度增量及角度加增量进行加法运算，以得到对应电机的当前周期的开环角度。所述加法器1415供多个电机复用，可有效减小成本，如图14所示，在时钟作用下，首先处理通道0对应的电机，启动脉冲有效，加法器对通道0的数据进行加法运算；处理完成后处理通道1对应的电机，同样，启动脉冲有效，加法器对通道1的数据进行加法运算；逐步类推，逐个完成各电机的开环角度的计算。
需要说明的是，所述角度加速控制模块14的工作原理参见实施例一，在此不一一赘述。
如图10所示，所述比例积分调节模块15连接于所述第一坐标转换模块11、所述处理器12及所述参考电流自增模块13的输出端，基于直轴电流Id、直轴参考电流Idref、交轴电流Iq 及交轴参考电流Iqref进行比例积分调节运算，得到直轴电压Ud和交轴电压Uq。
具体地，所述比例积分调节模块15包含一积分器电路；实际应用中，任意能实现比例积分运算的结构均适用于本发明的比例积分调节模块15，在此不一一赘述。使用直轴电流Id及直轴参考电流Idref参与磁场定向控制的比例积分调节运算得到直轴电压Ud；使用交轴电流Iq及交轴参考电流Iqref进参与磁场定向控制的比例积分调节运算得到交轴电压Uq。
所述控制信号产生模块基于所述第二坐标转换模块的输出信号产生所述电机的控制信号；
所述驱动模块连接于所述控制信号产生模块的输出端，基于所述控制信号产生所述电机的驱动信号并驱动所述电机启动。
如图10所示，所述第二坐标转换模块16连接于所述角度加速控制模块14及所述比例积分调节模块15的输出端，对所述直轴电压Ud和所述交轴电压Uq进行坐标转换，得到三相电压。
具体地，在本实施例中，所述第二坐标转换模块16为Clark逆变换和/或Park逆变换，所述直轴电压Ud和所述交轴电压Uq经过第n次异步拖动角度θn的正余弦值参与磁场定向控制的Clark/Park逆变换，得到三相电压(Uu，Uv，Uw)。
如图10所示，所述控制信号产生模块17基于所述第二坐标转换模块16的输出信号产生所述电机19的控制信号。
具体地，在本实施例中，所述控制信号产生模块17产生SVPWM信号。
如图10所示，所述驱动模块18连接于所述控制信号产生模块17的输出端，基于所述控制信号产生所述电机19的驱动信号，并驱动所述电机19启动。
具体地，在本实施例中，所述驱动模块18包括驱动板(如，电机驱动器电路板)，将低压域信号转变为高压域信号以驱动电机19运转。在实际使用中，任意能基于电机的控制信号驱动电机运转的电路结构均适用于本发明，不以本实施例为限。
需要说明的是，对于多电机启动的应用场景，所述驱动模块18的数量需要与电机19的数量保持一致。
如图10所示，所述电机19连接于所述驱动模块18的输出端，受所述驱动模块18的驱动工作。
具体地，在本实施中，所述电机19为无位置传感器的永磁同步电机。在实际使用中，任意无位置传感器的电机或有位置传感器的电机均适用，不以本实施例为限。
本发明在角度加速控制模块中保留多个通道的启动信息(包括但不限于开环角度，开环 角度增量，角度加增量)，处理器可通过访问同一组寄存器组，实现对任意通道的电机的参数访问和电机启动。采用分时复用方式同一时刻仅选择一路通道的信息进行电机的启动，计算结束后然后再选择下一路通道信息进行下一路电机的启动。多通道的计算过程均不需要处理器参与，仅当计算完成才通知处理器调整角度加增量Δ2θ及交轴参考电流增量，极大的减轻了处理器的负担，且可轻松可扩展成任意通道。
本发明通过角度θ，开环角度增量Δθ以及角度加增量Δ2θ的设置更易于硬件实现，只需要加法器和限幅器的重复使用，就可以完成启动过程，花费少量硬件资源，换取CPU资源的释放，缩短了软件人员为了电机能更顺畅平滑启动而规划加速曲线的时间；使用平滑启动在进行速率切换时减轻电机转动的“换挡”感觉；同时因为加入了角度加增量的概念，加快了启动进程，缩短电机启动时间，提高了电机启动的成功率，在一定范围内减小启动反转的几率。
综上所述，本发明提供一种电机启动方法及电机启动电路，包括：1)获取转子的当前位置；2)基于所述转子的当前位置及电机的转动方向对所述电机进行异步拖动，使开环角度逐步增大至目标启动开环角度，交轴参考电流逐步增大；其中，在异步拖动的过程中开环角度增量随时间的变化逐步增大，进而实现平滑启动；3)所述电机进入闭环控制模式。本发明的电机启动方法及电机启动电路引入开环角度，开环角度增量以及角度加增量，使得启动电路更易于硬件实现，只需要一个加法器的重复使用，就可以完成启动过程，花费硬件资源少，换取CPU资源的释放；通过调整开环角度增量实现平滑开启，在进行速率切换时减轻电机转动的“换挡”感觉；引入角度加增量，大大加快启动进程，在一定范围内抑制启动反转的概率；可扩展至任意组电机，且各电机的启动复用同一组计算逻辑，降低成本。所以，本发明有效克服了现有技术中的种种缺点而具高度产业利用价值。
上述实施例仅例示性说明本发明的原理及其功效，而非用于限制本发明。任何熟悉此技术的人士皆可在不违背本发明的精神及范畴下，对上述实施例进行修饰或改变。因此，举凡所属技术领域中具有通常知识者在未脱离本发明所揭示的精神与技术思想下所完成的一切等效修饰或改变，仍应由本发明的权利要求所涵盖。

Claims (15)

  1. 一种电机启动方法，其特征在于，所述电机启动方法至少包括：
    1)获取转子的当前位置；
    2)基于所述转子的当前位置及电机的转动方向对所述电机进行异步拖动，使开环角度逐步增大至目标启动开环角度，交轴参考电流逐步增大；其中，在异步拖动的过程中开环角度增量随时间的变化逐步增大，进而实现平滑启动；
    3)所述电机进入闭环控制模式。
  2. 根据权利要求1所述的电机启动方法，其特征在于：所述开环角度满足：
    θn＝θn-1+Δθn，Δθn＝Δθn-1+Δ2θ；
    其中，θn为当前周期的所述开环角度，θn-1为上一周期的所述开环角度，Δθn为当前周期的开环角度增量，Δθn-1为上一周期的开环角度增量，Δ2θ为角度加增量。
  3. 根据权利要求2所述的电机启动方法，其特征在于：步骤2)中分阶段调整所述开环角度，同一阶段内各周期的所述开环角度的角度加增量为恒定值，各阶段的所述开环角度的角度加增量随时间的变化逐步增大。
  4. 根据权利要求2或3所述的电机启动方法，其特征在于：步骤2)中第i阶段所述开环角度的角度加增量满足：

    其中，Δ2θi为第i阶段所述开环角度的角度加增量，i为大于等于1的自然数；Δθin为第i阶段最后一个周期的目标角度增量；Δθi0为第i阶段第一个周期的开环角度增量；Ti为第i阶段的时长；f为电机驱动频率；N为第i阶段的目标转速；p为电机的极对数；当i≥2时，Δθi0＝Δθ(i-1)n，Δθ(i-1)n为第(i-1)阶段最后一个周期的目标角度增量。
  5. 根据权利要求4所述的电机启动方法，其特征在于：当各阶段的开环角度增量达到对应阶段的目标角度增量时，触发角速度达标中断信号，清除角度加增量及交轴参考电流增量；并重新计算下一阶段的角度加增量及交轴参考电流增量，或维持当前周期的开环角度增量 及交轴参考电流。
  6. 一种电机启动电路，其特征在于，所述电机启动电路至少包括：
    采样模块、第一坐标转换模块、处理器、参考电流自增模块、角度加速控制模块、比例积分调节模块、第二坐标转换模块、控制信号产生模块、驱动模块及电机；
    所述采样模块对所述电机的电流进行采样；
    所述第一坐标转换模块连接于所述采样模块及所述角度加速控制模块的输出端，对所述采样模块的输出信号进行坐标转换，得到直轴电流和交轴电流；
    所述处理器提供直轴参考电流、交轴参考电流、交轴参考电流增量、初始角度、初始开环角度增量及角度加增量；
    所述参考电流自增模块连接于所述处理器的输出端，基于上一周期的交轴参考电流及所述交轴参考电流增量得到当前周期的交轴参考电流；
    所述角度加速控制模块连接于所述处理器的输出端，基于所述初始角度、所述初始开环角度增量及所述角度加增量将开环角度调整至目标启动开环角度；其中，开环角度增量随时间的变化逐步增大；
    所述比例积分调节模块连接于所述第一坐标转换模块、所述处理器及所述参考电流自增模块的输出端，基于直轴电流、直轴参考电流、交轴电流及交轴参考电流进行比例积分调节运算，得到直轴电压和交轴电压；
    所述第二坐标转换模块连接于所述角度加速控制模块及所述比例积分调节模块的输出端，对所述直轴电压和所述交轴电压进行坐标转换，得到三相电压；
    所述控制信号产生模块基于所述第二坐标转换模块的输出信号产生所述电机的控制信号；
    所述驱动模块连接于所述控制信号产生模块的输出端，基于所述控制信号产生所述电机的驱动信号并驱动所述电机启动。
  7. 根据权利要求6所述的电机启动电路，其特征在于：所述角度加速控制模块包括加法单元及正余弦计算单元；
    所述加法单元获取上一周期的开环角度、上一周期的开环角度增量及当前周期角度加增量进行加法运算，以得到当前周期的开环角度增量及当前周期的开环角度；
    所述正余弦计算单元连接于所述加法单元的输出端，对所述加法单元输出的开环角度进行正弦和余弦计算，所述正余弦计算单元输出的正弦和余弦用于电机启动控制。
  8. 根据权利要求7所述的电机启动电路，其特征在于：所述角度加速控制模块还包括上限控制单元；
    所述上限控制单元连接所述加法单元，当开环角度增量达到阶段性目标角度增量时，发出角速度达标中断信号；当开环角度增量小于对应阶段的目标角度增量时，控制所述加法单元基于上一周期的开环角度与当前周期的开环角度增量进行加法运算，得到当前周期的开环角度。
  9. 根据权利要求7或8所述的电机启动电路，其特征在于：所述加法单元包括寄存器及加法器；
    所述寄存器中存储开环角度、开环角度增量及角度加增量；
    所述加法器连接所述寄存器，对上一周期的开环角度、上一周期的开环角度增量及角度加增量进行加法运算，以得到当前周期的开环角度增量及当前周期的开环角度。
  10. 根据权利要求7或8所述的电机启动电路，其特征在于：所述加法单元包括多路复用器、加法器及至少两个寄存器；
    各寄存器中分别存储各电机的开环角度、开环角度增量及角度加增量；
    所述多路复用器连接于各寄存器的输出端，选择各寄存器中的一个，并输出被选中寄存器中的数据；
    所述加法器连接所述多路复用器的输出端，对所述多路复用器输出端的上一周期的开环角度、上一周期的开环角度增量及角度加增量进行加法运算，以得到当前周期的开环角度增量及当前周期的开环角度。
  11. 根据权利要求6所述的电机启动电路，其特征在于：所述驱动模块包括驱动板，将低压域信号转变为高压域信号，以驱动电机运转。
  12. 根据权利要求6所述的电机启动电路，其特征在于：所述电机为无位置传感器的永磁同步电机。
  13. 根据权利要求10所述的电机启动电路，其特征在于：所述多路复用器根据选择控制信号按通道顺序逐一选通，或根据选择控制信号按需要设定选通顺序。
  14. 根据权利要求10所述的电机启动电路，其特征在于：所述加法器供多个电机复用，其中，所述加法器在时钟作用下，
    首先处理一个通道对应的电机，启动脉冲有效，对该一个通道的数据进行加法运算；
    然后处理下一个通道对应的电机，启动脉冲有效，对该下一个通道的数据进行加法运算，以逐个完成各电机的开环角度的计算。
  15. 根据权利要求6所述的电机启动电路，其特征在于：所述第二坐标转换模块实现Clark逆变换和/或Park逆变换，所述直轴电压和所述交轴电压参与磁场定向控制的Clark逆变换和/或Park逆变换，得到三相电压。
PCT/CN2023/114363 2022-10-10 2023-08-23 电机启动方法及电机启动电路 WO2024078146A1 (zh)

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