Compressor control method of vehicle-mounted refrigerator, controller and vehicle-mounted refrigerator

Abstract

The invention relates to a compressor control method of a vehicle-mounted refrigerator, a controller and the vehicle-mounted refrigerator, and the method comprises the steps that firstly, an alpha-axis voltage vector and a beta-axis voltage vector of a compressor are obtained, and then the amplitude of a target voltage vector is determined according to vector module values of the alpha-axis voltage vector and the beta-axis voltage vector of a motor; and then determining a jitter frequency at the current moment according to the amplitude of the target voltage vector and a preset center frequency, generating a target PWM signal based on the jitter frequency at the current moment, and finally driving a motor by using the target PWM signal. Therefore, according to the method, the target PWM signal used for driving the motor is generated based on the jitter frequency, the magnetic field radiation is reduced in a frequency jitter mode, the jitter frequency in the method is generated based on the current running state of the compressor, the problem that the magnetic field radiation is excessively suppressed or is not sufficiently suppressed can be prevented, and the reliability of the compressor is improved. And the inhibition requirement of the current compressor is accurately matched, and the operation stability and energy efficiency of the compressor are further optimized.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of compressor control, in particular to a compressor control method, a controller and a vehicle refrigerator of a vehicle refrigerator. BACKGROUND

[0002] The core components of the compressor of the vehicle refrigerator are the controller and the motor. In the working process of the compressor, the controller generally adopts the inductionless FOC (Field Oriented Control) method to control the motor. However, the inductionless FOC technology is prone to produce excessive magnetic field radiation in the high-frequency switching process, especially in the low-frequency band, which is prone to cause the magnetic field radiation to exceed the standard, thereby affecting the vehicle environment and possibly affecting the working performance and service life of the compressor. SUMMARY

[0003] The present application at least solves one of the above technical problems to some extent. To this end, the present application provides a compressor control method, a controller and a vehicle refrigerator of a vehicle refrigerator, which can reduce magnetic field radiation by frequency jittering and dynamically adjust the jittering frequency according to the actual running state of the compressor, thereby further optimizing the stability and energy efficiency of the compressor operation.

[0004] In a first aspect, an embodiment of the present application provides a compressor control method of a vehicle refrigerator, the method comprising: obtaining an alpha-axis voltage vector and a beta-axis voltage vector of a motor of the compressor; determining an amplitude of a target voltage vector according to a vector modulus of the alpha-axis voltage vector and the beta-axis voltage vector of the motor; determining a jittering frequency at a current time according to the amplitude of the target voltage vector and a preset center frequency; generating a target PWM signal based on the jittering frequency at the current time; driving the motor by using the target PWM signal.

[0005] In some embodiments, the determining of the amplitude of the target voltage vector according to the vector modulus of the alpha-axis voltage vector and the beta-axis voltage vector of the motor comprises: the amplitude of the target voltage vector is obtained by the following formula: ; wherein, the amplitude of the target voltage vector is, the vector modulus of the alpha-axis voltage vector and the beta-axis voltage vector of the motor is, the alpha-axis voltage vector of the motor is, the beta-axis voltage vector of the motor is.

[0006] In some embodiments, the determining the jitter frequency at the current time according to the amplitude of the target voltage vector and the preset center frequency comprises: determining a frequency interval of the jitter frequency according to the amplitude of the target voltage vector and the preset center frequency; discretizing the frequency interval to obtain the jitter frequency corresponding to each time; selecting the jitter frequency at the current time from the jitter frequencies corresponding to each time.

[0007] In some embodiments, the determining the frequency interval of the jitter frequency comprises: the maximum jitter frequency is obtained by: Fmax = Fcenter + (b Uref); wherein, Fmax is the maximum jitter frequency, Fcenter is the preset center frequency, b is an adjustment coefficient, and Uref is the amplitude of the target voltage vector; the minimum jitter frequency is obtained by: Fmin = Fcenter + (-b Uref); wherein, Fmin is the minimum jitter frequency; the frequency interval of the jitter frequency is determined as [Fmin, Fmax].

[0008] In some embodiments, the method further comprises: judging whether the maximum jitter frequency is greater than a first preset threshold; if yes, determining the upper limit value of the frequency interval of the jitter frequency as the first preset threshold; judging whether the minimum jitter frequency is less than a second preset threshold; if yes, determining the lower limit value of the frequency interval of the jitter frequency as the second preset threshold.

[0009] In some embodiments, the discretizing the frequency interval to obtain the jitter frequency corresponding to each time comprises: the jitter frequency corresponding to each time is obtained by: ; wherein, is the jitter frequency corresponding to j time, Fmax is the maximum jitter frequency, Fmin is the minimum jitter frequency, i is the number of discretization points, j is a discrete increment, and j belongs to any integer in 1 to i.

[0010] In some embodiments, the generating the target PWM signal based on the dithering frequency at the current time point comprises: modifying a period count value of the PWM signal generation module to the dithering frequency at the current time point, so that the PWM signal generation module generates the corresponding target PWM signal.

[0011] In some embodiments, before the generating the target PWM signal based on the dithering frequency at the current time point, the method further comprises: obtaining a speed change amount of the motor within a preset time length; determining whether the speed change amount exceeds a third preset threshold; if yes, generating the target PWM signal using a preset switching frequency; if no, starting the step of generating the target PWM signal based on the dithering frequency at the current time point.

[0012] In a second aspect, the embodiments of the present application provide a controller, comprising at least one processor; and a memory connected with the at least one processor in communication; wherein the memory stores instructions executable by the at least one processor, and the instructions are executed by the at least one processor to enable the at least one processor to perform the compressor control method of the vehicle-mounted refrigerator.

[0013] In a third aspect, the embodiments of the present application provide a vehicle-mounted refrigerator, comprising a whole machine controller and a compressor, wherein the compressor comprises a motor and the controller as described above, the whole machine controller is connected with the controller, and the controller is further connected with the motor.

[0014] Compared with the prior art, the application has at least the following beneficial effects: in the compressor control method of the vehicle-mounted refrigerator in the application, first, the alpha-axis voltage vector and the beta-axis voltage vector of the compressor are obtained, then the amplitude of the target voltage vector is determined according to the vector modulus of the alpha-axis voltage vector and the beta-axis voltage vector of the motor, the dithering frequency at the current moment is determined according to the amplitude of the target voltage vector and the preset center frequency, the target PWM signal is generated based on the dithering frequency at the current moment, and finally the motor is driven by using the target PWM signal. Therefore, the compressor control method of the vehicle-mounted refrigerator generates the target PWM signal for driving the motor based on the dithering frequency, reduces the magnetic field radiation in the form of frequency dithering, and the dithering frequency in the method is obtained according to the alpha-axis voltage vector and the beta-axis voltage vector of the motor of the compressor. The alpha-axis voltage vector and the beta-axis voltage vector of the motor represent the running state of the current compressor, so that the dithering frequency in the method is generated based on the running state of the current compressor. Compared with the method of using a fixed dithering frequency, the method can prevent the problems of excessive suppression of magnetic field radiation or insufficient suppression of magnetic field radiation, accurately match the suppression demand of the current compressor, and further optimize the running stability and energy efficiency of the compressor. BRIEF DESCRIPTION OF DRAWINGS

[0015] One or more embodiments are illustrated by way of example in the figures that form a part of this patent document. These illustrations are not intended to limit the application in any way but are intended to illustrate the application in accordance with its principles. In the drawings, like reference numerals indicate like elements, unless otherwise specified. The drawings in which:

[0016] Figure 1 is a structural schematic diagram of a vehicle-mounted refrigerator provided by an embodiment of the application; Figure 2 is a structural schematic diagram of a controller provided by an embodiment of the application; Figure 3 is a flowchart of one of the compressor control methods of a vehicle-mounted refrigerator provided by an embodiment of the application; Figure 4 is a flowchart of step S103 in Figure 3 Figure 5a is a schematic diagram of low-frequency magnetic field radiation test data before a frequency dithering method is added, provided by an embodiment of the application; Figure 5b is a schematic diagram of low-frequency magnetic field radiation test data after a frequency dithering method is added, provided by an embodiment of the application; Figure 6 is a structural schematic diagram of a compressor control device of a vehicle-mounted refrigerator provided by an embodiment of the application. DETAILED DESCRIPTION

[0017] ​In order to make the purposes, technical solutions and advantages of the present application clearer, the present application will be further described in detail below with reference to the drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present application and not used to limit the present application. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative work fall within the scope of the present application.

[0018] It should be noted that the various features of the embodiments of the present application can be combined with each other without conflict, and all fall within the protection scope of the present application. In addition, although the functional modules are divided in the device schematic diagram, and the logical order is shown in the flowchart, in some cases, the steps shown or described can be executed in a different order from the module division in the device or the order in the flowchart. Furthermore, the "first", "second", "third" and the like used in the present application do not limit the data and execution order, but only distinguish the same items or similar items with basically the same function and effect.

[0019] Please refer to Figure 1 , Figure 1 is a circuit structure schematic diagram of a vehicle refrigerator provided by the embodiments of the present application. As Figure 1 shown, the vehicle refrigerator 100 includes a whole machine controller 10, an evaporator 20, a condenser 30 and a compressor 40, wherein the whole machine controller 10 is connected with the compressor 40.

[0020] The compressor 40 compresses the low-temperature and low-pressure gas from the evaporator 20 into high-temperature and high-pressure liquid through a motor, and then sends it to the condenser 30. And through the capillary, it is injected into the evaporator 20, the pressure drops suddenly, the liquid refrigerant becomes gaseous, and a large amount of heat in the air is absorbed through the cooling fins.

[0021] The whole machine controller 10 and the compressor 40 communicate through the LIN / CAN bus. The whole machine controller 10 sends instructions to the compressor 40 to control the working power of the compressor 40, start or stop the compressor 40. Specifically, the whole machine controller 10 can send target speed or target power instructions to the compressor 40, and the compressor 40 can control the target speed or target power instructions by using current loop and speed loop control. The speed loop control is mainly used for state switching and speed PID control with a period of Tms, and the current loop control is mainly used for phase current reading, observer algorithm, SVPWM, current PID control, and synchronization with the PWM period. In parameter debugging, the current loop is adjusted first, and then the current loop parameters are adjusted through the current waveform in the pre-positioning stage and the open-loop stage, and then the speed loop PI parameters are adjusted.

[0022] The compressor 40 comprises a controller 402 and a motor 401 connected with the controller 402, and the controller 402 is connected with the whole-machine controller 10. During the operation of the compressor 40, the controller 402 receives the instruction issued by the whole-machine controller 10, and can perform fault detection on the motor system voltage, current and the like, and then reports the fault state to the whole-machine controller 10 through LIN. The controller 402 can also output a PWM signal according to the instruction issued by the whole-machine controller 10 through a PID or SMC control algorithm, and the PWM signal controls the working state of a three-phase bridge, thereby controlling the speed, current or power of the motor 401.

[0023] The motor 401 can be a permanent magnet synchronous motor (PMSM), and the working principle thereof is to generate a magnetic field on the rotor by using a permanent magnet, when three-phase current is passed into the stator winding, a rotating magnetic field is generated, the rotating magnetic field interacts with the permanent magnet magnetic field on the rotor, and a synchronous rotating electromagnetic torque is generated, thereby driving the motor rotor to rotate. In some embodiments, the motor 401 can also be a brushless direct current motor (BLDC), which is an electric motor that realizes the conversion of electric energy into mechanical energy through electronic steering. In other embodiments, the motor 401 can also be other types of suitable motors, and the embodiments of the present application do not make any limitation in this regard.

[0024] The motor 401 mostly adopts a non-inductive field-oriented control (FOC) during the operation, and the non-inductive FOC driving technology is widely used in the compressor driving of the vehicle-mounted refrigerator due to the characteristics of high efficiency and high precision. However, the non-inductive FOC technology is prone to generate excessive magnetic field radiation during high-frequency switching, especially in the low-frequency band, for example, in the 100 kHz-200 kHz band, which is prone to cause excessive magnetic field radiation, thereby affecting the vehicle environment and possibly affecting the working performance and service life of the compressor.

[0025] Based on the above reasons, the embodiments of the present application provide a compressor control method of a vehicle-mounted refrigerator, which first acquires an α-axis voltage vector and a β-axis voltage vector of the compressor, then determines the amplitude of a target voltage vector according to the vector modulus of the α-axis voltage vector and the β-axis voltage vector of the motor, and then determines the jitter frequency at the current moment according to the amplitude of the target voltage vector and a preset center frequency, generates a target PWM signal based on the jitter frequency at the current moment, and finally drives the motor by using the target PWM signal.

[0026] Therefore, the compressor control method of the vehicle refrigerator generates a target PWM signal for driving the motor based on the dithering frequency, reduces the magnetic field radiation in the form of frequency dithering, and the dithering frequency in the method is obtained according to the alpha-axis voltage vector and the beta-axis voltage vector of the motor of the compressor, the alpha-axis voltage vector and the beta-axis voltage vector of the motor representing the current operating state of the compressor, so that the dithering frequency in the method is generated based on the current operating state of the compressor, and compared with the method of using a fixed dithering frequency, the method can prevent the problems of excessive suppression of the magnetic field radiation or insufficient suppression of the magnetic field radiation, accurately match the suppression demand of the current compressor, and further optimize the operating stability and energy efficiency of the compressor.

[0027] Please refer to Figure 2 , Figure 2 is a hardware structure schematic diagram of a controller provided by an embodiment of the present application. The controller 402 includes at least one processor 4021 (for example, a processor in an embodiment of the present application) and a memory 4022 connected by a system bus or other means of communication. Figure 2 The controller 402 can exist in the form of a chip.

[0028] The memory 4022 stores instructions executable by the at least one processor 4021, and the instructions are executed by the at least one processor 4021. The processor 4021 is used to provide computing and control capabilities to execute related commands, for example, to control the compressor 40 to execute any one of the compressor control methods of the vehicle refrigerator provided by the embodiments of the present application.

[0029] The memory 4022 is a non-transitory computer readable storage medium, which can be used to store non-transitory software programs, non-transitory computer executable programs and modules, such as program instructions / modules corresponding to the compressor control method of the vehicle refrigerator provided by the embodiments of the present application. The processor 4021 can implement the compressor control method of the vehicle refrigerator in any one of the method embodiments by running the non-transitory software programs, instructions and modules stored in the memory 4022. Specifically, the memory 4022 can include a high-speed random access memory, and can also include a non-transitory memory, for example, at least one magnetic disk storage device, a flash memory device, or other non-transitory solid-state storage device. In some embodiments, the memory 4022 can also include a memory remotely arranged with respect to the processor 4021, and these remote memories can be connected to the processor 4021 through a network. Examples of the above-mentioned network include but are not limited to the Internet, an intranet, a local area network, a mobile communication network, and a combination thereof.

[0030] In some embodiments, the controller 402 can be a general processor, a digital signal processor (DSP), an application-specific integrated circuit (ASIC), a field programmable gate array (FPGA), a single-board computer, an ARM (Acorn RISC Machine), or other programmable logic device, discrete gate or transistor logic, discrete hardware components, or any combination of these components. Also, the controller 402 can be any conventional processor, controller, microcontroller, or state machine. The controller 402 can also be implemented as a combination of computing devices, such as a combination of a DSP and a microprocessor, a plurality of microprocessors, one or more microprocessors in conjunction with a DSP core, and / or any other such configuration.

[0031] The embodiment of the present application provides a compressor control method of a vehicle-mounted refrigerator. Figure 3 , Figure 3 A flowchart of the compressor control method of the vehicle-mounted refrigerator is provided for the embodiment of the present application. The method S100 includes but is not limited to the following steps: S101: obtaining an alpha-axis voltage vector and a beta-axis voltage vector of a motor of the compressor; The motor of the compressor is controlled by the non-inductive FOC control. The non-inductive FOC control controls the vector of the current, so that the magnetic field of the motor is relatively oriented with the rotor magnetic field, thereby achieving the optimal torque output.

[0032] The core module of the non-inductive FOC control can be divided into two parts: signal acquisition and processing, and decoupling control. First, the current sampling module is responsible for processing the ADC voltage signal fed back by the hardware into an actual current signal, providing a basic feedback for subsequent control. The rotor position estimation module is the key to non-inductive control, which does not rely on physical sensors, but estimates the rotor position and speed through algorithms such as sliding model observer and flux observer by using motor current, voltage and other data. The coordinate transformation module converts the three-phase current (Ia, Ib, Ic) into alpha-axis current and beta current in two-dimensional coordinate system through Clarke transformation, and further converts it into d-axis current and q-axis current in the rotating coordinate system synchronized with the rotor through Park transformation, simplifying the complex alternating current motor control to direct current control, and realizing the matching of current vector direction and motor magnetic field orientation.

[0033] Another part of the core is the closed-loop control and drive execution module. The speed control module (speed loop) takes the target speed (Speed_ref) input from the outside as the reference, combines the speed feedback provided by the rotor position estimation module, calculates the speed error through the PI controller, and generates the d-axis and q-axis current reference values (iq_ref & id_ref). The current control module (current loop) includes two PI controllers. One PI controller receives the d-axis current reference value, compares it with the d-axis current feedback output by the current sampling module, and generates the d-axis voltage vector U_d. The other PI controller receives the q-axis current reference value, compares it with the q-axis current feedback output by the current sampling module, and generates the q-axis voltage vector U_q. The d-axis voltage vector U_d and the q-axis voltage vector U_q are then output as the α-β axis voltage vectors U_α / U_β through Park inverse transformation.

[0034] Finally, the SVPWM module outputs the corresponding PWM signals based on the α-axis voltage vector and the β-axis voltage vector of the motor. The PWM signals drive the inverter to output high-frequency alternating current, which acts on the motor three-phase winding, achieving precise speed regulation and torque control of the motor.

[0035] The α-axis voltage vector and the β-axis voltage vector of the motor are the decomposition quantities of the expected voltage space vector in the SVPWM module, and their amplitude and variation law are directly related to the motor speed and load. When the motor is at high speed and heavy load, the motor needs to generate more torque to overcome the load, so the FOC control increases the q-axis voltage vector (U_q). After Park inverse transformation, the vector modulus of U_α and U_β will significantly increase, and the back electromotive force will also increase at high speed, so higher U_α and U_β are needed to offset the influence of the back electromotive force to maintain stable current. When the motor is at low speed and light load, the torque demand is low, U_q is small, and the back electromotive force is weak, so the vector modulus of U_α and U_β will be significantly lower than that in the high-speed heavy-load condition.

[0036] When the operating state of the motor changes, the vector modulus of the α-axis voltage vector and the β-axis voltage vector will also change. If the vector modulus is large, the motor is in a heavy load state, and if the vector modulus is small, the motor is in a light load state. Therefore, the operating state of the motor can be reflected by the vector modulus of the α-axis voltage vector and the β-axis voltage vector. By adding the vector modulus of the α-axis voltage vector and the β-axis voltage vector to the calculation of the dithering frequency, the dithering frequency can be adjusted according to the actual operating state of the motor to better match the demand of the motor.

[0037] S102: determining the amplitude of the target voltage vector according to the vector modulus of the α-axis voltage vector and the β-axis voltage vector of the motor; In some embodiments, the vector modulus of the α-axis voltage vector and the β-axis voltage vector of the motor is determined as the amplitude of the target voltage vector, i.e. the amplitude of the target voltage vector is obtained by the following formula: (1) wherein, is a magnitude of the target voltage vector, is a vector modulus of the α-axis voltage vector and the β-axis voltage vector of the motor, is the α-axis voltage vector of the motor, is the β-axis voltage vector of the motor.

[0038] In some embodiments, the magnitude of the target voltage vector is positively correlated with the vector modulus of the α-axis voltage vector and the β-axis voltage vector of the motor. That is, the magnitude of the target voltage vector is obtained by: (2) wherein, is a magnitude of the target voltage vector, is a vector modulus of the α-axis voltage vector and the β-axis voltage vector of the motor, is the α-axis voltage vector of the motor, is the β-axis voltage vector of the motor, is an adjustment coefficient, and is a positive number.

[0039] Thus, the operating state of the motor is represented by the magnitude of the target voltage vector. The greater the magnitude of the target voltage vector, the greater the probability that the motor is in a heavy load state. The smaller the magnitude of the target voltage vector, the greater the probability that the motor is in a light load state.

[0040] S103: determining a jitter frequency at the current moment according to the magnitude of the target voltage vector and a preset center frequency; The preset center frequency is a center frequency in the jitter frequency range and is a constant value set according to experience. The jitter frequency fluctuates up and down around the preset center frequency, and the fluctuation range is calculated according to the magnitude of the target voltage vector. A corresponding triangular wave function is generated according to the fluctuation range, so that the jitter frequency conforms to the low-high-low jitter rule and does not cause a sudden change in the jitter frequency.

[0041] Specifically, as shown in Figure 4 step S103 includes: S1031: determining a frequency interval of the jitter frequency according to the magnitude of the target voltage vector and the preset center frequency; The frequency interval of the jitter frequency is the jitter range of the jitter frequency, which is the fluctuation range. The jitter frequency needs to be valued within the frequency interval. If the value exceeds the frequency interval, it may cause a sudden change in the jitter frequency, so that the subsequently generated target PWM signal cannot accurately control the motor.

[0042] In some embodiments, a fixed frequency interval can be set, for example, the frequency interval is [Fcenter- f, Fcenter+ f, and the frequency interval is discretized at fixed intervals or non-fixed intervals to obtain the jitter frequency corresponding to each time.

[0043] The jitter frequency obtained based on the above manner does not exceed a certain range, and under certain conditions, the obtained jitter frequency is appropriate. However, the jitter frequency obtained based on the above manner is a fixed value, and even if the interval is changed, the obtained jitter frequency does not change with the operating state of the motor, and cannot accurately match the demand of the motor.

[0044] Therefore, in some embodiments, the frequency interval of the jitter frequency is determined according to the amplitude of the target voltage vector and the preset center frequency. The amplitude of the target voltage vector is related to the operating state of the motor, so that the frequency interval of the jitter frequency also changes with the change of the operating state of the motor, and accurately matches the demand of the motor.

[0045] Specifically, the maximum jitter frequency is obtained by the following formula: Fmax=Fcenter+(b·Uref) (3) Wherein, Fmax is the maximum jitter frequency, Fcenter is the preset center frequency, b is the adjustment coefficient, and Uref is the amplitude of the target voltage vector.

[0046] The minimum jitter frequency is obtained by the following formula: Fmin=Fcenter+(-b·Uref) (4) Wherein, Fmin is the minimum jitter frequency.

[0047] Then the frequency interval of the jitter frequency is determined as [Fmin, Fmax], and the jitter frequency corresponding to each time is taken from the frequency interval.

[0048] It should be noted that the adjustment coefficient b is a coefficient representing the characteristics of the system, which is the correlation coefficient of the amplitude Uref of the target voltage vector and the jitter frequency range, and can be obtained by debugging.

[0049] In some embodiments, if the maximum jitter frequency obtained by formula (3) is too large or the minimum jitter frequency obtained by formula (4) is too small, it may still cause the mutation of the jitter frequency. Therefore, the frequency interval of the jitter frequency needs to be limited within an appropriate range.

[0050] First, it is judged whether the maximum jitter frequency is greater than a first preset threshold value. If it is greater, the upper limit value of the frequency interval of the jitter frequency is determined as the first preset threshold value. Then it is judged whether the minimum jitter frequency is less than a second preset threshold value. If it is less, the lower limit value of the frequency interval of the jitter frequency is determined as the second preset threshold value.

[0051] If the first preset threshold is Flimit and the second preset threshold is -Flimit, the frequency interval of the jitter frequency needs to be limited between [-Flimit, Flimit], if the maximum jitter frequency Fmax is greater than Flimit, the maximum jitter frequency Fmax is set as Flimit, and the frequency interval of the jitter frequency is set as [Fmin, Fmax], wherein Fmax is Flimit, or if the minimum jitter frequency Fmin is less than -Flimit, the minimum jitter frequency Fmin is set as -Flimit, and the frequency interval of the jitter frequency is set as [Fmin, Fmax], wherein Fmin is -Flimit, or if the maximum jitter frequency Fmax is greater than Flimit and the minimum jitter frequency Fmin is less than -Flimit, the maximum jitter frequency Fmax is set as Flimit, the minimum jitter frequency Fmin is set as -Flimit, and the frequency interval of the jitter frequency is set as [Fmin, Fmax], wherein Fmin is -Flimit and Fmax is Flimit.

[0052] In the above manner, the frequency interval can change with the running state of the motor, and the frequency interval of the jitter frequency can be limited within a suitable range, so that the triangular wave function generated according to the frequency interval subsequently meets the low-high-low jitter rule, and the jitter frequency does not suddenly change, thereby improving the reliability of control and the stability of operation.

[0053] S1032: discretizing the frequency interval to obtain a jitter frequency corresponding to each time point; The discretization of the frequency interval to obtain a jitter frequency corresponding to each time point is to generate a triangular wave sequence according to the frequency interval, and the triangular wave sequence is composed of each time point and a jitter frequency corresponding to each time point.

[0054] The jitter frequency corresponding to each time point is obtained by the following formula: (5) Wherein, is the jitter frequency corresponding to the jth time point, Fmax is the maximum jitter frequency, Fmin is the minimum jitter frequency, i is the number of discretization points, j is the discrete increment, and j is any integer in 1 to i.

[0055] For example, if i is 10, j is any integer in 1 to 10, and the frequency interval is discretized into 10 jitter frequencies F1 to F10 corresponding to each time point by formula (5). 10 Wherein, i is the number of updates in a triangular wave period sequence, which can be set as needed.

[0056] S1033: Select the jitter frequency for the current moment from the jitter frequencies corresponding to each moment.

[0057] The jitter frequencies corresponding to each moment are F1 to F i If the current time is k, then the jitter frequency at the current time is F. k For example, if i is 10, then the jitter frequencies corresponding to each time point are F1 to F... 10 If k is 3, then from F1 to F 10 Select F3 as the jitter frequency for the current moment.

[0058] S104: Generate a target PWM signal based on the jitter frequency at the current moment; The current jitter frequency replaces the original switching frequency to generate the corresponding target PWM signal. A common PWM signal generation module is a hardware timer. The generation method is based on the hardware timer's counting mechanism. The basic steps for generating a PWM signal are: (1) Configure the period of the hardware timer A key function of hardware timers is to generate fixed time intervals. By setting the timer's counting period, the frequency of the PWM signal can be determined. Each count of the hardware timer is equivalent to generating a "clock pulse," thus determining the frequency of the PWM signal. The hardware timer's counter resets each time it overflows, generating a new PWM cycle.

[0059] (2) Configure the duty cycle of the timer Hardware timers are not only responsible for period control, but can also control the duration of high and low levels of the output through comparators.

[0060] When frequency jitter is required, the current jitter frequency F is set. k This is set to the PWM frequency control module, which modifies the period count value of the hardware timer to the jitter frequency F at the current moment. k This causes the hardware timer to generate the corresponding target PWM signal.

[0061] In some embodiments, before generating a target PWM signal based on the current jitter frequency to achieve frequency jitter, it is necessary to determine whether the current operating state of the motor is suitable for frequency jitter or for changing the switching frequency.

[0062] If the motor is currently operating in a volatile or unstable state, or is in a condition of rapid speed change, it is not suitable to change the switching frequency and frequency jitter should not be performed. If the motor is currently operating in a relatively stable state or the speed is relatively stable, then frequency jitter measures can be taken.

[0063] Thus, before the frequency jittering measure is taken, the motor speed variation amount in a preset time length is obtained, it is judged whether the speed variation amount exceeds a third preset threshold, if yes, a preset switching frequency is used to generate the target PWM signal, if no, the switching frequency based on the jittering frequency at the current time is used to generate the target PWM signal.

[0064] If the speed variation amount exceeds the third preset threshold, it indicates that the current motor speed variation is large, for example, the motor is in a working condition with sharp speed change such as starting, accelerating, decelerating, etc., the motor operating state is unstable, the frequency jittering measure cannot be taken, and the original preset switching frequency is still used to generate the target PWM signal to avoid oscillation.

[0065] If the speed variation amount does not exceed the third preset threshold, it indicates that the current motor speed variation is not large, the motor is stable, and the frequency jittering measure can be taken to generate the target PWM signal at the jittering frequency at the current time to reduce the magnetic field radiation.

[0066] In some embodiments, whether to take the frequency jittering measure can also be determined by the speed variation rate and a fourth preset threshold, for example, if the motor speed variation rate exceeds the fourth preset threshold, it indicates that the motor operating state is unstable and the speed variation is large, the preset switching frequency is used to generate the target PWM signal, if the motor speed variation rate is less than the fourth preset threshold, it indicates that the motor operating state is relatively stable, the frequency jittering measure can be taken, and the target PWM signal is generated at the jittering frequency at the current time.

[0067] S105: The motor is driven by using the target PWM signal.

[0068] The target PWM signal is used to drive the inverter, so that the inverter converts the target PWM signal into high-frequency alternating current, the high-frequency alternating current drives the three-phase winding of the motor, and the motor reaches the target speed. That is, the target PWM signal acts on the inverter, the inverter converts the target PWM signal into the actual voltage and current required to drive the motor, so that the motor reaches the target speed.

[0069] In the embodiments of the present application, when frequency jittering is needed, the frequency of the target PWM signal is adjusted to the jittering frequency at the current time, that is, the frequency of the target PWM signal is jittered (i.e., jittered frequency) around the preset center frequency, so that the electromagnetic energy originally concentrated at a single switching frequency and its harmonics is dispersed into a wider frequency bandwidth, thereby reducing the radiation peak value at a specific frequency point and avoiding exceeding the magnetic field emission (MFE) standard limit value. The essence is "energy dispersion" rather than "energy elimination". Compared with fixed frequency PWM modulation, the jittering frequency technology disperses the electromagnetic radiation spectrum at integer multiples of the preset center frequency, reduces the peak value, and avoids exceeding the MFE standard limit value.

[0070] For the same controller, the low-frequency magnetic field radiation test data before joining the frequency jitter method is as shown in FIG. 1, and the low-frequency magnetic field radiation test data after joining the frequency jitter method is as shown in FIG. 2. Figure 5a Figure 5b Figure 5a Figure 5b The horizontal axis in FIG. 1 and FIG. 2 is frequency, the vertical axis is magnetic field strength, the curve L1 is a magnetic field radiation curve, and the straight line L2 is an EMC standard limit value. As can be seen from FIG. 1, when the frequency exceeds 100k, the magnetic field strengths at the 4-point, 5-point, and 6-point positions all exceed the MFE standard limit value. As can be seen from FIG. 2, after joining the frequency jitter method of the present application, the magnetic field strengths at all positions do not exceed the MFE standard limit value, and especially in the sensitive frequency band (100k-200k) interval, the magnetic field radiation is effectively suppressed, and the magnetic field strength is lower than the MFE standard limit value. Figure 5a Figure 5b

[0071] In summary, the compressor control method of the vehicle-mounted refrigerator generates a target PWM signal for driving the motor based on jitter frequency, reduces magnetic field radiation in a frequency jitter manner, and the jitter frequency in the method is obtained according to the alpha-axis voltage vector and the beta-axis voltage vector of the motor of the compressor. The alpha-axis voltage vector and the beta-axis voltage vector of the motor represent the current operating state of the compressor. Therefore, the jitter frequency in the method is generated based on the current operating state of the compressor. Compared with the fixed jitter frequency method, the method can prevent the problems of excessive suppression of magnetic field radiation or insufficient suppression of magnetic field radiation, accurately match the suppression requirements of the current compressor, and further optimize the operating stability and energy efficiency of the compressor.

[0072] It should be noted that in the above various embodiments, there is no certain sequence between the above steps. Those skilled in the art can understand from the description of the embodiments of the present application that the above steps can have different execution sequences in different embodiments, that is, they can be executed in parallel, or they can be executed in exchange, and the like.

[0073] As another aspect of the present application, the present application provides a compressor control device of a vehicle-mounted refrigerator. The compressor control device of the vehicle-mounted refrigerator can be a software module, which includes a plurality of instructions stored in a memory in the electric governor, and a processor can access the memory to call the instructions for execution to complete the compressor control method of the vehicle-mounted refrigerator described in the above various embodiments.

[0074] ​​​​​In some embodiments, the compressor control device of the vehicle-mounted refrigerator can also be built by hardware devices, for example, the compressor control device of the vehicle-mounted refrigerator can be built by one or more chips, and each chip can work in coordination with each other to complete the compressor control method of the vehicle-mounted refrigerator described in each of the above embodiments. For another example, the compressor control device of the vehicle-mounted refrigerator can also be built by various logic devices, such as general-purpose processors, digital signal processors (DSP), application-specific integrated circuits (ASIC), field programmable gate arrays (FPGA), single-chip microcomputers, ARM (Acorn RISC Machine) or other programmable logic devices, discrete gates or transistor logic, discrete hardware components, or any combination of these components.

[0075] Please refer to Figure 6 , Figure 6 The compressor control device of the vehicle-mounted refrigerator provided in the embodiments of the present application comprises an acquisition module 201, a first determination module 202, a second determination module 203, a generation module 204 and a driving module 205.

[0076] The acquisition module 201 is configured to acquire an alpha-axis voltage vector and a beta-axis voltage vector of a motor of the compressor, the first determination module 202 is configured to determine an amplitude of a target voltage vector according to a vector modulus of the alpha-axis voltage vector and the beta-axis voltage vector of the motor, the second determination module 203 is configured to determine a dithering frequency at a current time according to the amplitude of the target voltage vector and a preset center frequency, the generation module 204 is configured to generate a target PWM signal based on the dithering frequency at the current time, and the driving module 205 is configured to drive the motor by using the target PWM signal.

[0077] Therefore, the compressor control device of the vehicle-mounted refrigerator generates a target PWM signal for driving the motor based on the dithering frequency, reduces the magnetic field radiation in the form of frequency dithering, and the dithering frequency in the method is obtained according to the alpha-axis voltage vector and the beta-axis voltage vector of the motor of the compressor. The alpha-axis voltage vector and the beta-axis voltage vector of the motor represent the running state of the current compressor, so that the dithering frequency in the method is generated based on the running state of the current compressor. Compared with the method of using a fixed dithering frequency, the method can prevent the problems of excessive suppression of the magnetic field radiation or insufficient suppression of the magnetic field radiation, accurately match the suppression demand of the current compressor, and further optimize the running stability and energy efficiency of the compressor.

[0078] It should be noted that, since the compressor control device 200 of the vehicle-mounted refrigerator and the compressor control method of the vehicle-mounted refrigerator in the above embodiments are based on the same application concept, the corresponding contents in the above method embodiments are also applicable to the device embodiments, which will not be described in detail here.

[0079] The embodiment of the present application also provides a non-transitory computer-readable storage medium, which stores computer executable instructions, and the computer executable instructions are executed by one or more processors, for example, one processor 4021 in the processor 402, so that the one or more processors can execute the compressor control method of the vehicle refrigerator in any method embodiment. Figure 2 The embodiment of the present application also provides a non-transitory computer-readable storage medium, which stores computer executable instructions, and the computer executable instructions are executed by one or more processors, for example, one processor 4021 in the processor 402, so that the one or more processors can execute the compressor control method of the vehicle refrigerator in any method embodiment.

[0080] The embodiment of the present application also provides a computer program product, which comprises a computer program stored on a non-transitory computer-readable storage medium, and the computer program comprises program instructions, and when the program instructions are executed by a controller 402, the controller 402 executes the compressor control method of the vehicle refrigerator in any method embodiment.

[0081] In summary, the compressor control method of the vehicle refrigerator generates a target PWM signal for driving the motor based on the dithering frequency, reduces the magnetic field radiation in the form of frequency dithering, and the dithering frequency in the method is obtained according to the alpha-axis voltage vector and the beta-axis voltage vector of the motor of the compressor. The alpha-axis voltage vector and the beta-axis voltage vector of the motor represent the current operating state of the compressor. Therefore, the dithering frequency in the method is generated based on the current operating state of the compressor. Compared with the method of using a fixed dithering frequency, the method can prevent the problems of excessive suppression of the magnetic field radiation or insufficient suppression of the magnetic field radiation, accurately match the suppression requirements of the current compressor, and further optimize the operating stability and energy efficiency of the compressor.

[0082] The device or equipment embodiments described above are only schematic, wherein the unit modules illustrated as separate components can or can not be physically separated, and the components illustrated as module units can or can not be physical units, that is, can be located in one place, or can be distributed on multiple network module units. Part or all of the modules can be selected according to actual needs to achieve the purpose of the embodiment scheme.

[0083] From the above description of the embodiments, those skilled in the art can clearly understand that the embodiments can be implemented by means of software plus a general hardware platform, and of course can also be implemented by hardware. Based on such understanding, the above technical solutions essentially or in the sense of related technology can be embodied in the form of a software product, which can be stored in a computer readable storage medium, such as a ROM / RAM, a magnetic disk, an optical disk, etc., and includes a plurality of instructions to make a computer device (which can be a personal computer, a server, or a network device, etc.) execute the compressor control method of the vehicle refrigerator in each embodiment or some parts of the embodiment.

[0084] Finally, it should be noted that: the above examples are only used to illustrate the technical solutions of the present application, but not to limit them; under the idea of the present application, the technical features in the above examples or different embodiments can also be combined, the steps can be implemented in any order, and there are many other changes of different aspects of the present application as described above, which are not provided in details for simplicity; although the present application has been described in detail with reference to the foregoing examples, those skilled in the art should understand that: it can still modify the technical solutions recorded in the foregoing examples, or make equivalent replacement for part of the technical features; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the scope of the technical solutions of the embodiments of the present application.

Claims

1. A compressor control method for a vehicle-mounted refrigerator, characterized in that, The method includes: Obtain the α-axis voltage vector and β-axis voltage vector of the compressor motor; The magnitude of the target voltage vector is determined based on the vector magnitudes of the α-axis voltage vector and the β-axis voltage vector of the motor. The jitter frequency at the current moment is determined based on the amplitude of the target voltage vector and the preset center frequency; The target PWM signal is generated based on the jitter frequency at the current moment; The target PWM signal is used to drive the motor.

2. The method according to claim 1, characterized in that, The step of determining the magnitude of the target voltage vector based on the vector magnitudes of the α-axis and β-axis voltage vectors of the motor includes: The magnitude of the target voltage vector is obtained by the following formula: ; in, The magnitude of the target voltage vector. The vector magnitudes of the α-axis voltage vector and the β-axis voltage vector of the motor are given. Let α be the voltage vector of the motor. Let be the β-axis voltage vector of the motor.

3. The method according to claim 1, characterized in that, The step of determining the jitter frequency at the current moment based on the amplitude of the target voltage vector and the preset center frequency includes: The frequency range of the jitter frequency is determined based on the amplitude of the target voltage vector and the preset center frequency; The frequency range is discretized to obtain the jitter frequency corresponding to each moment; Select the jitter frequency for the current moment from the jitter frequencies corresponding to each moment.

4. The method according to claim 3, characterized in that, The step of determining the frequency range of the jitter frequency based on the amplitude of the target voltage vector and the preset center frequency includes: The maximum jitter frequency is obtained using the following formula: Fmax = Fcenter + (b·Uref); Where Fmax is the maximum jitter frequency, Fcenter is the preset center frequency, b is the adjustment coefficient, and Uref is the amplitude of the target voltage vector; The minimum jitter frequency can be obtained using the following formula: Fmin = Fcenter + (-b·Uref); Wherein, Fmin is the minimum jitter frequency; The frequency range of the jitter frequency is defined as [Fmin, Fmax].

5. The method according to claim 4, characterized in that, The method further includes: Determine whether the maximum jitter frequency is greater than a first preset threshold; If it is greater than the threshold value, the upper limit of the frequency range of the jitter frequency is determined as the first preset threshold value; Determine whether the minimum jitter frequency is less than a second preset threshold; If it is less than the threshold value, the lower limit of the frequency range of the jitter frequency is determined as the second preset threshold value.

6. The method according to claim 3, characterized in that, The discretization of the frequency range to obtain the jitter frequency corresponding to each moment includes: The jitter frequency at each moment can be obtained using the following formula: ； in, Let Fmax be the jitter frequency corresponding to time j, Fmin be the minimum jitter frequency, i be the number of discretization points, j be the discrete increment, and j be any integer from 1 to i.

7. The method according to claim 1, characterized in that, The generation of the target PWM signal based on the jitter frequency at the current moment includes: The period count value of the PWM signal generation module is modified to the jitter frequency at the current moment, so that the PWM signal generation module generates the corresponding target PWM signal.

8. The method according to any one of claims 1-7, characterized in that, Before generating the target PWM signal based on the jitter frequency at the current moment, the method further includes: Obtain the change in motor speed over a preset time period; Determine whether the change in rotational speed exceeds a third preset threshold; If so, the target PWM signal is generated using a preset switching frequency; If not, then begin the step of generating the target PWM signal based on the jitter frequency at the current moment.

9. A controller, characterized in that, The controller includes: At least one processor; and a memory communicatively connected to the at least one processor; wherein the memory stores instructions executable by the at least one processor to enable the at least one processor to perform the compressor control method for a vehicle refrigerator as described in any one of claims 1-8.

10. A vehicle-mounted refrigerator, characterized in that, It includes a whole machine controller and a compressor, wherein the compressor includes a motor and a controller as described in claim 9, the whole machine controller is connected to the controller, and the controller is also connected to the motor.

Images