A method and apparatus for scalar control of a brushless DC motor

Abstract

This application discloses a scalar control method and apparatus for a brushless DC motor. The method includes: obtaining the motor operating frequency feedback value for the current control cycle based on t1(ZC) and t0(ZC); extracting the high-frequency component from the motor operating frequency feedback value for the current control cycle; obtaining the dynamic correction amount of the emission frequency to be superimposed; calculating the low-frequency component from the motor operating frequency feedback value for the current control cycle; generating the adaptive frequency scaling factor and the voltage correction amount for the current control cycle; and generating the motor drive control signal for the current control cycle. Compared to other scalar control schemes, this scheme can effectively improve the dynamic and steady-state performance of the brushless DC motor. Furthermore, this scheme has a smaller computational load and lower hardware implementation cost, requiring only at least one phase of motor output voltage as an analog comparator input for obtaining the zero-crossing signal of the motor back EMF voltage, without the need for analog sampling.

Description

Technical Field

[0001] This application relates to the field of brushless DC motor control technology, specifically to a scalar control method and device for brushless DC motors. Background Technology

[0002] As a type of permanent magnet synchronous motor, brushless DC motors are currently widely used in industrial control, medical equipment, automotive, consumer goods, home appliances, and aerospace fields. Specific products include industrial fan drivers, water pump drivers, textile machines, wire drawing machines, air compressors, CNC machine tools, printers, optical disc drives, cooling fans, windshield wipers, electric windows, refrigerators, air conditioners, high-speed blowers, and so on.

[0003] Currently, most brushless DC motor drivers use a six-step commutation square wave control strategy to control the operation of brushless DC motors. However, under medium and low speed operating conditions, the square wave control strategy causes large torque fluctuations and significant operating noise in brushless DC motors. Existing solutions use current vector control to achieve low-noise control of brushless DC motors, but such solutions involve complex coordinate transformations, have a large computational load, and require current sensors that increase system costs. Summary of the Invention

[0004] The purpose of this invention is to provide a scalar control method for brushless DC motors to at least solve one of the above-mentioned technical problems.

[0005] One aspect of the present invention provides a scalar control method for a brushless DC motor, the scalar control method for a brushless DC motor comprising:

[0006] Step 1: Obtain the rising edge time t1(ZC) of the last ZC occurrence and the rising edge time t0(ZC) of the ZC that occurred before t1(ZC) directly adjacent to t1(ZC);

[0007] Step 2: Obtain the motor operating frequency feedback value for the current control cycle based on t1(ZC) and t0(ZC);

[0008] Step 3: Extract the high-frequency components from the motor operating frequency feedback value of the current control cycle;

[0009] Step 4: Add the high-frequency component of the current control cycle as a correction value to the transmission frequency to obtain the dynamic correction value of the transmission frequency to be added.

[0010] Step 5: Based on the operating frequency feedback value of the current control cycle and the high-frequency component of the current control cycle, calculate the low-frequency component in the motor operating frequency feedback value of the current control cycle.

[0011] Step 6: Based on t1(ZC) and t0(ZC), the voltage correction amount of the previous control cycle, the low-frequency component of the current control cycle, and the basic command voltage corresponding to the given reference frequency of the system, generate the adaptive frequency scaling factor and the voltage correction amount of the current control cycle.

[0012] Step 7: Generate the motor drive control signal for the current control cycle based on the system-given reference frequency, the adaptive frequency scaling factor for the current control cycle, the dynamic correction amount of the superimposed wave frequency for the current control cycle, the voltage correction amount for the current control cycle, and the basic command voltage corresponding to the system-given reference frequency. Output the motor drive control signal for the current control cycle to the inverter to drive the brushless DC motor.

[0013] Optionally, the motor operating frequency feedback value for the current control cycle, obtained based on t1(ZC) and t0(ZC), is obtained using the following formula:

[0014] ;

[0015] Where t1(ZC) is the rising edge time of the last occurrence of ZC; t0(ZC) is the rising edge time of the ZC that is directly adjacent to t1(ZC) and occurs before it. The feedback value of the motor operating frequency in the current control cycle.

[0016] Optionally, the high-frequency component of the motor operating frequency feedback value in the current control cycle is extracted using the following formula:

[0017] ;

[0018] s is the high-frequency component in the current motor operating frequency feedback value, s is the complex frequency in the Laplace transform, and a is the filter coefficient of the high-pass filter; This is the feedback value of the motor operating frequency for the current control cycle.

[0019] Optionally, the low-frequency component of the motor operating frequency feedback value of the current control cycle is calculated based on the operating frequency feedback value of the current control cycle and the high-frequency component of the current control cycle, and obtained by the following formula:

[0020] ;

[0021] This is the feedback value of the motor operating frequency for the current control cycle; This refers to the high-frequency component in the current motor operating frequency feedback value; This refers to the low-frequency component in the motor operating frequency feedback value of the current control cycle.

[0022] Optionally, step 6: generating the adaptive frequency scaling factor and the voltage correction amount for the current control cycle based on t1(ZC) and t0(ZC), the voltage correction amount of the previous control cycle, and the low-frequency component of the current control cycle includes:

[0023] Calculate the adaptive voltage scaling factor and the adaptive frequency scaling factor based on t1(ZC) and t0(ZC);

[0024] The controller proportional coefficient and controller integral coefficient are generated based on the adaptive voltage proportional factor, the adaptive frequency proportional factor, and the basic command voltage corresponding to the system given reference frequency.

[0025] The voltage correction for the current control cycle is generated based on the controller's proportional gain, controller's integral gain, the system's given reference frequency, and the low-frequency component of the current control cycle.

[0026] Optionally, the adaptive voltage scaling factor and adaptive frequency scaling factor are obtained from t1(ZC) and t0(ZC) using the following formulas:

[0027] ;

[0028] t1(ZC) is the rising edge time of the last ZC occurrence; t0(ZC) is the rising edge time of the ZC that is directly adjacent to t1(ZC) and occurs before it. λ is the preset stall time; η is the adaptive voltage scaling factor; and η is the adaptive frequency scaling factor.

[0029] Optionally, the controller proportional coefficient and controller integral coefficient generated based on the adaptive voltage scaling factor, the adaptive frequency scaling factor, and the base command voltage corresponding to the system given reference frequency are obtained in the following way:

[0030] The controller parameters are adjusted based on the hysteresis switching rule. The hysteresis loop width is half of the adaptive voltage proportional factor λ. The proportional coefficient and integral coefficient of the controller are obtained by the following formula:

[0031] ;

[0032] ;

[0033] Where V_Corr is the voltage correction amount from the previous control cycle. The base command voltage is given to the system at the reference frequency, and w is the controller bandwidth. This is the proportional gain of the controller. λ is the controller integral coefficient; λ is the adaptive voltage proportional factor; when the voltage correction output by the controller is greater than λ times the command voltage, the controller parameters are switched to desaturation state; when the voltage correction output by the controller is less than λ / 2 times the command voltage, the controller parameters are switched to normal control state.

[0034] Optionally, the voltage correction amount for the current control cycle, generated based on the controller proportional coefficient, controller integral coefficient, system reference frequency, and low-frequency component of the current control cycle, is obtained using the following formula:

[0035] ;

[0036] A reference frequency is given to the system. This refers to the low-frequency component in the motor operating frequency feedback value of the current control cycle; This is the proportional gain of the controller. The integral coefficient of the controller; This is the voltage correction amount for the current control cycle.

[0037] Optionally, step 7: generating the motor drive control signal for the current control cycle based on the system-given reference frequency, the adaptive frequency scaling factor for the current control cycle, the dynamic correction amount of the transmission frequency to be superimposed in the current control cycle, the voltage correction amount for the current control cycle, and the basic command voltage corresponding to the system-given reference frequency includes:

[0038] The corrected transmission frequency is calculated using the following formula:

[0039] ;

[0040] A reference frequency is given to the system, and η is the adaptive frequency scaling factor for the current control cycle. This is the dynamic correction amount of the emission frequency to be superimposed in the current control cycle. The corrected transmission frequency;

[0041] The corrected wave angle is calculated using the following formula:

[0042] ;

[0043] Where θ is the corrected wave angle; The corrected transmission frequency;

[0044] The corrected transmitted voltage is calculated using the following formula:

[0045] ;

[0046] in, The system is given a base command voltage corresponding to a reference frequency. V represents the voltage correction amount for the current control cycle, where V is the corrected transmission voltage.

[0047] This application also provides a scalar control device for a brushless DC motor, the scalar control device for the brushless DC motor comprising:

[0048] The time acquisition module is used to acquire the rising edge time t1(ZC) of the last ZC occurrence and the rising edge time t0(ZC) of the ZC that occurred before t1(ZC) and is directly adjacent to t1(ZC).

[0049] A motor operating frequency feedback value acquisition module is used to acquire the motor operating frequency feedback value of the current control cycle based on t1(ZC) and t0(ZC).

[0050] A high-frequency component acquisition module is used to extract the high-frequency component from the motor operating frequency feedback value of the current control cycle based on the motor operating frequency feedback value of the current control cycle.

[0051] The transmission frequency dynamic correction amount acquisition module is used to superimpose the high frequency component of the current control cycle as the correction amount of the transmission frequency onto the transmission frequency, thereby obtaining the transmission frequency dynamic correction amount to be superimposed.

[0052] A low-frequency component acquisition module is used to calculate the low-frequency component in the motor operating frequency feedback value of the current control cycle based on the operating frequency feedback value of the current control cycle and the high-frequency component of the current control cycle.

[0053] The voltage correction acquisition module is used to generate the adaptive frequency scaling factor and the voltage correction amount of the current control cycle based on t1(ZC) and t0(ZC), the voltage correction amount of the previous control cycle, the low-frequency component of the current control cycle, and the basic command voltage corresponding to the given reference frequency of the system.

[0054] The motor drive control signal acquisition module is used to generate a motor drive control signal for the current control period based on the system given reference frequency, the adaptive frequency scaling factor of the current control period, the dynamic correction amount of the superimposed wave frequency of the current control period, the voltage correction amount of the current control period, and the basic command voltage corresponding to the system given reference frequency. The motor drive control signal of the current control period is then output to the inverter to drive the brushless DC motor.

[0055] The scalar control method for brushless DC motors in this application first acquires the back EMF voltage zero-crossing signal output by the analog comparator, and calculates the current operating frequency feedback value of the motor based on the back EMF zero-crossing signal. Then, it extracts the high-frequency component of the current operating frequency feedback value and uses this high-frequency component as a correction amount for the wave generation frequency to be superimposed on the wave generation frequency to suppress the dynamic oscillation of the motor. Finally, it calculates the low-frequency component of the current operating frequency feedback value and uses this low-frequency component and the system given frequency as the input of the controller. The voltage correction amount output by the controller is used to correct the wave generation voltage to improve the steady-state performance of the motor.

[0056] Compared to other scalar control schemes, this scheme can effectively improve the dynamic and steady-state performance of brushless DC motors. Moreover, this scheme has a smaller computational load and lower hardware implementation cost. It only requires at least one phase of motor output voltage as the input of an analog comparator to obtain the zero-crossing signal of the motor back EMF voltage, without the need for other analog quantity sampling. Attached Figure Description

[0057] Figure 1 This is a flowchart of a scalar control method for a brushless DC motor according to an embodiment of this application.

[0058] Figure 2 This is a schematic diagram of a scalar control method for a brushless DC motor according to an embodiment of this application. Detailed Implementation

[0059] To make the objectives, technical solutions, and advantages of this application clearer, the technical solutions in the embodiments of this application will be described in more detail below with reference to the accompanying drawings. In the drawings, the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The described embodiments are some, but not all, embodiments of this application. The embodiments described below with reference to the accompanying drawings are exemplary and intended to explain this application, and should not be construed as limiting this application. All other embodiments obtained by those skilled in the art based on the embodiments of this application without creative effort are within the scope of protection of this application. The embodiments of this application will be described in detail below with reference to the accompanying drawings.

[0060] like Figure 1 The scalar control method shown for brushless DC motors includes:

[0061] Step 1: Obtain the rising edge time t1(ZC) of the last ZC occurrence and the rising edge time t0(ZC) of the ZC that occurred before t1(ZC) directly adjacent to t1(ZC);

[0062] Step 2: Obtain the motor operating frequency feedback value for the current control cycle based on t1(ZC) and t0(ZC);

[0063] Step 3: Extract the high-frequency components from the motor operating frequency feedback value of the current control cycle;

[0064] Step 4: Add the high-frequency component of the current control cycle as a correction value to the transmission frequency to obtain the dynamic correction value of the transmission frequency to be added.

[0065] Step 5: Based on the operating frequency feedback value of the current control cycle and the high-frequency component of the current control cycle, calculate the low-frequency component in the motor operating frequency feedback value of the current control cycle.

[0066] Step 6: Based on t1(ZC) and t0(ZC), the voltage correction amount of the previous control cycle, the low-frequency component of the current control cycle, and the basic command voltage corresponding to the given reference frequency of the system, generate the adaptive frequency scaling factor and the voltage correction amount of the current control cycle.

[0067] Step 7: Generate the motor drive control signal for the current control cycle based on the system-given reference frequency, the adaptive frequency scaling factor for the current control cycle, the dynamic correction amount of the superimposed wave frequency for the current control cycle, the voltage correction amount for the current control cycle, and the basic command voltage corresponding to the system-given reference frequency. Output the motor drive control signal for the current control cycle to the inverter to drive the brushless DC motor.

[0068] In this embodiment, the motor operating frequency feedback value for the current control cycle, obtained based on t1(ZC) and t0(ZC), is obtained using the following formula:

[0069] (3)

[0070] Where t1(ZC) is the rising edge time of the last occurrence of ZC; t0(ZC) is the rising edge time of the ZC that is directly adjacent to t1(ZC) and occurs before it. The feedback value of the motor operating frequency in the current control cycle.

[0071] In this embodiment, the high-frequency component of the motor operating frequency feedback value in the current control cycle is extracted using the following formula:

[0072] (4)

[0073] s is the high-frequency component in the current motor operating frequency feedback value, s is the complex frequency in the Laplace transform, and a is the filter coefficient of the high-pass filter; This is the feedback value of the motor operating frequency for the current control cycle.

[0074] In this embodiment, the low-frequency component of the motor operating frequency feedback value of the current control cycle is calculated based on the operating frequency feedback value of the current control cycle and the high-frequency component of the current control cycle, and is obtained through the following formula:

[0075] (5)

[0076] This is the feedback value of the motor operating frequency for the current control cycle; This refers to the high-frequency component in the current motor operating frequency feedback value; This refers to the low-frequency component in the motor operating frequency feedback value of the current control cycle.

[0077] In this embodiment, step 6: generating the adaptive frequency scaling factor and the voltage correction amount for the current control cycle based on t1(ZC) and t0(ZC), the voltage correction amount of the previous control cycle, and the low-frequency component of the current control cycle includes:

[0078] Calculate the adaptive voltage scaling factor and the adaptive frequency scaling factor based on t1(ZC) and t0(ZC);

[0079] The controller proportional coefficient and controller integral coefficient are generated based on the adaptive voltage proportional factor, the adaptive frequency proportional factor, and the basic command voltage corresponding to the system given reference frequency.

[0080] The voltage correction for the current control cycle is generated based on the controller's proportional gain, controller's integral gain, the system's given reference frequency, and the low-frequency component of the current control cycle.

[0081] In this embodiment, the adaptive voltage scaling factor and adaptive frequency scaling factor are calculated based on t1(ZC) and t0(ZC) using the following formulas:

[0082] (9)

[0083] t1(ZC) is the rising edge time of the last ZC occurrence; t0(ZC) is the rising edge time of the ZC that is directly adjacent to t1(ZC) and occurs before it. λ is the preset stall time; η is the adaptive voltage scaling factor; and η is the adaptive frequency scaling factor.

[0084] In this embodiment, the controller proportional coefficient and controller integral coefficient generated based on the adaptive voltage scaling factor, the adaptive frequency scaling factor, and the base command voltage corresponding to the system's given reference frequency are obtained in the following manner:

[0085] The controller parameters are adjusted based on the hysteresis switching rule. The hysteresis loop width is half of the adaptive voltage proportional factor λ. The proportional coefficient and integral coefficient of the controller are obtained by the following formula:

[0086] (7)

[0087] (8)

[0088] Where V_Corr is the voltage correction amount from the previous control cycle. The base command voltage is given to the system at the reference frequency, and w is the controller bandwidth. This is the proportional gain of the controller. λ is the controller integral coefficient; λ is the adaptive voltage proportional factor; when the voltage correction output by the controller is greater than λ times the command voltage, the controller parameters are switched to desaturation state; when the voltage correction output by the controller is less than λ / 2 times the command voltage, the controller parameters are switched to normal control state.

[0089] In this embodiment, the voltage correction amount for the current control cycle, generated based on the controller proportional coefficient, controller integral coefficient, system reference frequency, and low-frequency component of the current control cycle, is obtained using the following formula:

[0090] (6)

[0091] A reference frequency is given to the system. This refers to the low-frequency component in the motor operating frequency feedback value of the current control cycle; This is the proportional gain of the controller. The integral coefficient of the controller; This is the voltage correction amount for the current control cycle.

[0092] In this embodiment, step 7: generating the motor drive control signal for the current control cycle based on the system-given reference frequency, the adaptive frequency scaling factor of the current control cycle, the dynamic correction amount of the transmission frequency to be superimposed in the current control cycle, the voltage correction amount of the current control cycle, and the basic command voltage corresponding to the system-given reference frequency includes:

[0093] The corrected transmission frequency is calculated using the following formula:

[0094] (10)

[0095] A reference frequency is given to the system, and η is the adaptive frequency scaling factor for the current control cycle. This is the dynamic correction amount of the emission frequency to be superimposed in the current control cycle. The corrected transmission frequency;

[0096] The corrected wave angle is calculated using the following formula:

[0097] (11)

[0098] Where θ is the corrected wave angle; The corrected transmission frequency;

[0099] The corrected transmitted voltage is calculated using the following formula:

[0100] (12)

[0101] in, The system is given a base command voltage corresponding to a reference frequency. V represents the voltage correction amount for the current control cycle, where V is the corrected transmission voltage.

[0102] The following is in conjunction with the appendix Figure 1 Appendix Figure 2 As this application is further elaborated, it is understood that the example does not constitute any limitation on this application.

[0103] Figure 2 is a block diagram of a scalar control scheme for a brushless DC motor. The meaning of the variable symbols transmitted by each line in Figure 2 is explained in detail below. Figure 2 In this system, apart from the inverter and the brushless DC motor, only the analog comparator module is a hardware analog device; all other modules are digital computing modules, meaning that all other modules can be implemented through software code or digital logic circuits. Figure 2 In this context, the space vector pulse width modulation module is a commonly used pulse width modulation module in the fields of power electronics and electrical drives. Other pulse width modulation modules with similar functions can also be used here.

[0104] Scalar control of conventional AC motors mainly involves the following two formulas:

[0105] (1)

[0106] (2)

[0107] In equations (1) and (2), Command voltage, For the command angle, The reference frequency value input to the system. The constant voltage-frequency ratio coefficient (also known as the motor back EMF constant) is used in the scalar control of conventional AC motors to control the command voltage. and instruction angle As input to the pulse width modulation module, it generates the switching signal for the power switch that drives the main circuit. Also known as the voltmeter voltage, defined For the transmission frequency, The angle at which the wave is emitted.

[0108] exist Figure 2 In this paper, the back EMF zero-crossing signal output by the analog comparator is defined as ZC. When ZC has a rising edge (either rising or falling edge is acceptable, but rising edge is used as an example here), the time when the current rising edge of ZC occurs is defined as t1(ZC), and the time when the adjacent previous rising edge of ZC occurred is defined as t0(ZC). The current operating frequency feedback value of the motor can be calculated based on the back EMF zero-crossing signal of the motor, and the calculation formula is shown in equation (3). The absolute value of the difference between t0(ZC) and t1(ZC) can be limited by the lower limit and the upper limit respectively according to the highest and lowest operating frequencies of the motor in the actual system.

[0109] Conventional AC motor scalar control often uses the sampled feedback current signal to perform oscillation suppression calculations to avoid dynamic oscillations during AC motor operation. However, current sampling significantly increases the hardware cost of the system. This solution only requires at least one phase of motor output voltage as the input of an analog comparator to obtain the zero-crossing signal of the motor back EMF voltage, without the need for other analog quantity sampling.

[0110] To suppress oscillations during motor operation, this scheme directly extracts the high-frequency component from the current motor operating frequency feedback value and superimposes it onto the transmission frequency as a correction factor to suppress oscillations during motor operation. There are many methods for extracting high-frequency components from a signal, such as high-pass filters, band-pass filters, notch filters, and fast Fourier analysis. Here, a high-pass filter is used as an example, and its calculation formula is shown in equation (4). Simultaneously, the low-frequency component in the current motor operating frequency feedback value can also be obtained by extracting this high-frequency component, and its calculation formula is shown in equation (5).

[0111] To improve the steady-state performance (including speed stability and steady-state efficiency) of the brushless DC motor control system, this scheme uses the low-frequency component and the given system frequency as inputs to the controller, and uses the voltage correction value output by the controller to correct the generated voltage. The calculation formula is shown in equation (6).

[0112] In equation (6), This is the voltage correction value output by the controller. To take into account the dynamic and steady-state performance of the system, a proportional-integral controller is used as an example here (other controllers are also acceptable; choose the appropriate controller according to the dynamic performance required by the actual system, such as proportional controllers, integral controllers, proportional-derivative controllers, and sliding mode controllers). and These are the proportional and integral coefficients of the controller.

[0113] To improve the zero-low speed load capacity of the brushless DC motor and prevent stalling during the zero-low speed heavy load start-up process, an adaptive anti-stalling method based on a preset stall time is used to adjust the controller parameters. Therefore, the calculation formulas for the proportional coefficient and integral coefficient of the controller are as shown in equations (7) and (8). In equations (7) and (8), when the voltage correction amount V_Corr output by the controller is greater than the command voltage... of When the value is 10 times, it means that the DC brushless motor is in the zero-low speed heavy-load start-up stage. This is because the current system is in a state where the actual motor speed is close to zero and the voltage correction amount V_Corr is large. At this time, the controller parameters are switched to the desaturation state.

[0114] To avoid frequent parameter switching, hysteresis switching is used here, with the hysteresis loop width being an adaptive voltage scaling factor. Half of the voltage correction value V_Corr output by the controller is less than the command voltage. of When the voltage is 2 times the reference frequency, the system's voltage correction V_Corr is small, and the actual motor speed is close to the target speed (i.e., the actual operating frequency of the motor is close to the system's input reference frequency). This means that the DC brushless motor has not stalled and is in normal load operation. At this time, the controller parameters are switched to normal control state.

[0115] Equation (9) is the formula for calculating the adaptive voltage scaling factor λ. In Equation (9), the absolute value of the difference between t0(ZC) and t1(ZC) is greater than the preset stall time. At this time, the upper limit of the adaptive voltage scaling factor λ is limited to 1. Preset stall time. The frequency is set based on the power device tolerance of the motor driver under zero-frequency heavy-load operation conditions. η is an adaptive frequency scaling factor. Since the scalar control zero-low-speed load start-up condition is similar to a DC brushless motor experiencing a short-term stall, the waveform frequency also needs to be adjusted. Synchronization adjustment is performed to prevent the brushless DC motor from losing synchronization under load, and the emission frequency is automatically reduced to improve the load-carrying capacity of the brushless DC motor when stall occurs.

[0116] As mentioned above, in order to improve the load-carrying capacity of the brushless DC motor, an adaptive frequency scaling factor η is introduced as a scaling factor for the emission frequency, while simultaneously... Figure 2 The mid-to-high frequency component f_Corr is superimposed on the scaled transmission frequency as a frequency correction amount to obtain the corrected transmission frequency, and its calculation formula is shown in Equation (10); the corrected transmission angle can be calculated using the corrected transmission frequency, and its calculation formula is shown in Equation (11); the corrected transmission voltage can be obtained by correcting the transmission voltage using the voltage correction amount output by the controller in Figure 2, and its calculation formula is shown in Equation (12).

[0117] This application also provides a scalar control device for a brushless DC motor, the scalar control device for the brushless DC motor comprising:

[0118] The time acquisition module is used to acquire the rising edge time t1(ZC) of the last ZC occurrence and the rising edge time t0(ZC) of the ZC that occurred before t1(ZC) and is directly adjacent to t1(ZC).

[0119] A motor operating frequency feedback value acquisition module is used to acquire the motor operating frequency feedback value of the current control cycle based on t1(ZC) and t0(ZC).

[0120] A high-frequency component acquisition module is used to extract the high-frequency component from the motor operating frequency feedback value of the current control cycle based on the motor operating frequency feedback value of the current control cycle.

[0121] The transmission frequency dynamic correction amount acquisition module is used to superimpose the high frequency component of the current control cycle as the correction amount of the transmission frequency onto the transmission frequency, thereby obtaining the transmission frequency dynamic correction amount to be superimposed.

[0122] A low-frequency component acquisition module is used to calculate the low-frequency component in the motor operating frequency feedback value of the current control cycle based on the operating frequency feedback value of the current control cycle and the high-frequency component of the current control cycle.

[0123] The voltage correction acquisition module is used to generate the adaptive frequency scaling factor and the voltage correction amount of the current control cycle based on t1(ZC) and t0(ZC), the voltage correction amount of the previous control cycle, the low-frequency component of the current control cycle, and the basic command voltage corresponding to the given reference frequency of the system.

[0124] The motor drive control signal acquisition module is used to generate a motor drive control signal for the current control period based on the system given reference frequency, the adaptive frequency scaling factor of the current control period, the dynamic correction amount of the superimposed wave frequency of the current control period, the voltage correction amount of the current control period, and the basic command voltage corresponding to the system given reference frequency. The motor drive control signal of the current control period is then output to the inverter to drive the brushless DC motor.

[0125] Although the present invention has been described in detail above with general descriptions and specific embodiments, modifications or improvements can be made to it, which will be obvious to those skilled in the art. Therefore, all such modifications or improvements made without departing from the spirit of the present invention fall within the scope of protection claimed by the present invention.

Claims

1. A scalar control method for a brushless DC motor, characterized in that, The scalar control method for brushless DC motors includes: Step 1: Obtain the rising edge time t1(ZC) of the last ZC occurrence and the rising edge time t0(ZC) of the ZC that occurred before t1(ZC) directly adjacent to t1(ZC); Step 2: Obtain the motor operating frequency feedback value for the current control cycle based on t1(ZC) and t0(ZC); Step 3: Extract the high-frequency components from the motor operating frequency feedback value of the current control cycle; Step 4: Add the high-frequency component of the current control cycle as a correction value to the transmission frequency to obtain the dynamic correction value of the transmission frequency to be added. Step 5: Based on the operating frequency feedback value of the current control cycle and the high-frequency component of the current control cycle, calculate the low-frequency component in the motor operating frequency feedback value of the current control cycle. Step 6: Based on t1(ZC) and t0(ZC), the voltage correction amount of the previous control cycle, the low-frequency component of the current control cycle, and the basic command voltage corresponding to the given reference frequency of the system, generate the adaptive frequency scaling factor and the voltage correction amount of the current control cycle. Step 7: Generate the motor drive control signal for the current control cycle based on the system-given reference frequency, the adaptive frequency scaling factor for the current control cycle, the dynamic correction amount of the superimposed wave frequency for the current control cycle, the voltage correction amount for the current control cycle, and the basic command voltage corresponding to the system-given reference frequency. Output the motor drive control signal for the current control cycle to the inverter to drive the brushless DC motor.

2. The scalar control method for brushless DC motors as described in claim 1, characterized in that, The motor operating frequency feedback value for the current control cycle, obtained based on t1(ZC) and t0(ZC), is obtained using the following formula: ； Where t1(ZC) is the rising edge time of the last occurrence of ZC; t0(ZC) is the rising edge time of the ZC that is directly adjacent to t1(ZC) and occurs before it. The feedback value of the motor operating frequency in the current control cycle.

3. The scalar control method for brushless DC motors as described in claim 2, characterized in that, The high-frequency component of the motor operating frequency feedback value in the current control cycle is extracted using the following formula: ； s is the high-frequency component in the current motor operating frequency feedback value, s is the complex frequency in the Laplace transform, and a is the filter coefficient of the high-pass filter; This is the feedback value of the motor operating frequency for the current control cycle.

4. The scalar control method for brushless DC motors as described in claim 3, characterized in that, The low-frequency component of the motor operating frequency feedback value for the current control cycle is calculated based on the operating frequency feedback value and the high-frequency component of the current control cycle, using the following formula: ； This is the feedback value of the motor operating frequency for the current control cycle; This refers to the high-frequency component in the current motor operating frequency feedback value; This refers to the low-frequency component in the motor operating frequency feedback value of the current control cycle.

5. The scalar control method for a brushless DC motor as described in claim 4, characterized in that, Step 6: Based on t1(ZC) and t0(ZC), the voltage correction amount of the previous control cycle, and the low-frequency component of the current control cycle, generating the adaptive frequency scaling factor and the voltage correction amount of the current control cycle includes: Calculate the adaptive voltage scaling factor and the adaptive frequency scaling factor based on t1(ZC) and t0(ZC); The controller proportional coefficient and controller integral coefficient are generated based on the adaptive voltage proportional factor, the adaptive frequency proportional factor, and the basic command voltage corresponding to the system given reference frequency. The voltage correction for the current control cycle is generated based on the controller's proportional gain, controller's integral gain, the system's given reference frequency, and the low-frequency component of the current control cycle.

6. The scalar control method for a brushless DC motor as described in claim 5, characterized in that, The adaptive voltage scaling factor and adaptive frequency scaling factor are calculated based on t1(ZC) and t0(ZC) using the following formulas: ； t1(ZC) is the rising edge time of the last ZC occurrence; t0(ZC) is the rising edge time of the ZC that is directly adjacent to t1(ZC) and occurs before it. Preset stall time; λ is the adaptive voltage scaling factor; η is the adaptive frequency scaling factor.

7. The scalar control method for a brushless DC motor as described in claim 6, characterized in that, The controller proportional coefficient and controller integral coefficient, generated based on the adaptive voltage proportional factor, the adaptive frequency proportional factor, and the base command voltage corresponding to the system given reference frequency, are obtained in the following manner: The controller parameters are adjusted based on the hysteresis switching rule. The hysteresis loop width is half of the adaptive voltage proportional factor λ. The proportional coefficient and integral coefficient of the controller are obtained by the following formula: ； ； Where V_Corr is the voltage correction amount from the previous control cycle. The base command voltage is given to the system at the reference frequency, and w is the controller bandwidth. This is the proportional gain of the controller. λ is the controller integral coefficient; λ is the adaptive voltage proportional factor; when the voltage correction output by the controller is greater than λ times the command voltage, the controller parameters are switched to desaturation state; when the voltage correction output by the controller is less than λ / 2 times the command voltage, the controller parameters are switched to normal control state.

8. The scalar control method for a brushless DC motor as described in claim 7, characterized in that, The voltage correction amount for the current control cycle, generated based on the controller proportional coefficient, controller integral coefficient, system reference frequency, and low-frequency component of the current control cycle, is obtained using the following formula: ； A reference frequency is given to the system. This refers to the low-frequency component in the motor operating frequency feedback value of the current control cycle; This is the proportional gain of the controller. The integral coefficient of the controller; This is the voltage correction amount for the current control cycle.

9. The scalar control method for a brushless DC motor as described in claim 8, characterized in that, Step 7: Generating the motor drive control signal for the current control cycle based on the system-given reference frequency, the adaptive frequency scaling factor of the current control cycle, the dynamic correction amount of the transmission frequency to be superimposed in the current control cycle, the voltage correction amount of the current control cycle, and the basic command voltage corresponding to the system-given reference frequency includes: The corrected transmission frequency is calculated using the following formula: ； A reference frequency is given to the system, and η is the adaptive frequency scaling factor for the current control cycle. This is the dynamic correction amount of the emission frequency to be superimposed in the current control cycle. The corrected transmission frequency; The corrected wave angle is calculated using the following formula: ； Where θ is the corrected wave angle; The corrected transmission frequency; The corrected transmitted voltage is calculated using the following formula: ； in, The system is given a base command voltage corresponding to a reference frequency. V represents the voltage correction amount for the current control cycle, where V is the corrected transmission voltage.

10. A scalar control device for a brushless DC motor, characterized in that, The scalar control device for the brushless DC motor includes: The time acquisition module is used to acquire the rising edge time t1(ZC) of the last ZC occurrence and the rising edge time t0(ZC) of the ZC that occurred before t1(ZC) and is directly adjacent to t1(ZC). A motor operating frequency feedback value acquisition module is used to acquire the motor operating frequency feedback value of the current control cycle based on t1(ZC) and t0(ZC). A high-frequency component acquisition module is used to extract the high-frequency component from the motor operating frequency feedback value of the current control cycle based on the motor operating frequency feedback value of the current control cycle. The transmission frequency dynamic correction amount acquisition module is used to superimpose the high frequency component of the current control cycle as the correction amount of the transmission frequency onto the transmission frequency, thereby obtaining the transmission frequency dynamic correction amount to be superimposed. A low-frequency component acquisition module is used to calculate the low-frequency component in the motor operating frequency feedback value of the current control cycle based on the operating frequency feedback value of the current control cycle and the high-frequency component of the current control cycle. The voltage correction acquisition module is used to generate the adaptive frequency scaling factor and the voltage correction amount of the current control cycle based on t1(ZC) and t0(ZC), the voltage correction amount of the previous control cycle, the low-frequency component of the current control cycle, and the basic command voltage corresponding to the given reference frequency of the system. The motor drive control signal acquisition module is used to generate a motor drive control signal for the current control period based on the system given reference frequency, the adaptive frequency scaling factor of the current control period, the dynamic correction amount of the superimposed wave frequency of the current control period, the voltage correction amount of the current control period, and the basic command voltage corresponding to the system given reference frequency. The motor drive control signal of the current control period is then output to the inverter to drive the brushless DC motor.

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