Refrigerator and compressor rotating speed control method thereof

Abstract

According to the refrigerator and the compressor rotating speed control method thereof, a PID control link is added in a frequency conversion controller, the heat dissipation process of the frequency conversion controller is achieved in a PID control mode on the premise that a heat dissipation device is not added, the control precision is high, deviation is small, and the phenomenon that a power device on the frequency conversion controller fails due to ultrahigh temperature can be avoided.

Description

Technical Field

[0001] The present invention relates to the field of refrigerators, and in particular to a refrigerator and a method for controlling the speed of a compressor thereof. Background Art

[0002] Household refrigerators and freezers, used in high-temperature and embedded environments, have low system heat exchange efficiency and limited heat dissipation space. To meet cooling demands, the compressor must run for extended periods, increasing the temperature rise of the compressor and inverter board. Power devices like IGBTs (Insulated Gate Bipolar Transistors) can fail when they reach their temperature limits. Therefore, temperature control of the inverter board is crucial during design to address the impact of temperature rise on heat dissipation performance. For example, after a variable frequency controller reaches a certain power output, the temperature of the power devices on the controller increases over time, exceeding the temperature limit and causing damage. Existing technology typically installs an NTC thermistor on the variable frequency controller to sample the power device temperature. Before the temperature reaches the limit, the compressor speed is reduced. However, this approach rarely achieves the desired effect, primarily because the temperature rise of the variable frequency power device and the speed are not linearly related. Simply adjusting the compressor speed results in poor cooling performance. Summary of the Invention

[0003] The purpose of the embodiments of the present invention is to provide a refrigerator and a compressor speed control method thereof. Without adding heat dissipation components, a PID control method is used to achieve heat dissipation of a frequency converter controller. The control accuracy is high and the deviation is small, which can avoid the phenomenon of power components on the frequency converter controller failing due to excessively high temperatures.

[0004] To achieve the above object, an embodiment of the present invention provides a refrigerator, comprising:

[0005] a box body, in which at least one storage chamber is formed;

[0006] A door is provided at the opening of the storage chamber and is used to open and close the storage chamber;

[0007] A compressor, disposed in the box, comprising a motor and a compressor body, and configured to provide power for a refrigeration cycle of the refrigerator;

[0008] A frequency conversion controller is provided in the housing. The frequency conversion controller is provided with a PID module. The frequency conversion controller is configured as follows:

[0009] Acquiring electrical parameters of the motor in the compressor, and calculating output power based on the electrical parameters and preset frequency conversion characteristic parameters;

[0010] When the output power does not match the preset target power, the output power is used as the input of the PID module, and a reference speed is output to the compressor through PID regulation so that the motor runs at the reference speed.

[0011] As an improvement to the above solution, the electrical parameters include a q-axis current measurement value, a q-axis voltage measurement value, a d-axis current measurement value, and a d-axis voltage measurement value.

[0012] As an improvement to the above solution, the calculating of the output power according to the electrical parameters and the preset frequency conversion characteristic parameters includes:

[0013] Calculating the product of the q-axis current measurement value and the q-axis voltage measurement value to obtain the q-axis power;

[0014] Calculating the product of the d-axis current measurement value and the d-axis voltage measurement value to obtain the d-axis power;

[0015] The output power is obtained by calculating the product of the power sum of the q-axis power and the d-axis power and the frequency conversion characteristic parameter.

[0016] As an improvement to the above solution, the frequency conversion controller is further configured as follows:

[0017] calculating the back electromotive force of the motor;

[0018] When the back electromotive force generated by the motor is greater than the bus voltage, the motor is subjected to flux weakening control.

[0019] As an improvement to the above solution, a three-phase bridge is further provided in the frequency conversion controller, and the three-phase bridge is respectively connected to the PID module and the compressor, and the three-phase bridge includes a bridge circuit composed of a plurality of insulated gate bipolar transistors.

[0020] To achieve the above object, an embodiment of the present invention further provides a refrigerator compressor speed control method, comprising:

[0021] Obtaining electrical parameters of the motor in the frequency conversion controller, and calculating the output power based on the electrical parameters and preset frequency conversion characteristic parameters;

[0022] When the output power does not match the preset target power, the output power is used as the input of the PID module, and a reference speed is output to the compressor through PID regulation, so that the compressor runs at the reference speed.

[0023] As an improvement to the above solution, the electrical parameters include a q-axis current measurement value, a q-axis voltage measurement value, a d-axis current measurement value, and a d-axis voltage measurement value.

[0024] As an improvement to the above solution, the calculating of the output power according to the electrical parameters and the preset frequency conversion characteristic parameters includes:

[0025] Calculating the product of the q-axis current measurement value and the q-axis voltage measurement value to obtain the q-axis power;

[0026] Calculating the product of the d-axis current measurement value and the d-axis voltage measurement value to obtain the d-axis power;

[0027] The output power is obtained by calculating the product of the power sum of the q-axis power and the d-axis power and the frequency conversion characteristic parameter.

[0028] As an improvement to the above solution, the method further includes:

[0029] calculating the back electromotive force of the motor;

[0030] When the back electromotive force generated by the motor is greater than the bus voltage, the motor is subjected to flux weakening control.

[0031] Compared with the existing technology, the refrigerator and its compressor speed control method disclosed in the present invention add a PID control link in the frequency conversion controller. Without adding heat dissipation devices, the PID control method is used to realize the heat dissipation process of the frequency conversion controller. The control accuracy is high and the deviation is small, which can avoid the phenomenon of ultra-high temperature failure of the power devices on the frequency conversion controller. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] Figure 1 1 is a schematic diagram of the external structure of a refrigerator provided by an embodiment of the present invention;

[0033] Figure 2 This is a schematic diagram of the internal structure of a refrigerator provided by an embodiment of the present invention;

[0034] Figure 3 1 is a schematic structural diagram of a refrigeration system in a refrigerator provided by an embodiment of the present invention;

[0035] Figure 4 1 is a schematic structural diagram of a compressor cabin provided by an embodiment of the present invention;

[0036] Figure 5 1 is a schematic diagram of the connection between the frequency conversion controller and the compressor provided by an embodiment of the present invention;

[0037] Figure 6 This is a first working flow diagram of a frequency conversion controller in a refrigerator provided by an embodiment of the present invention;

[0038] Figure 7 Schematic diagram of a PID control link provided by an embodiment of the present invention;

[0039] Figure 8This is a second working flow diagram of the frequency conversion controller in the refrigerator provided by an embodiment of the present invention;

[0040] Figure 9 1 is a schematic diagram of the FOC framework of the motor in the variable frequency controller provided by an embodiment of the present invention;

[0041] Figure 10 This is a flow chart of a method for controlling the speed of a refrigerator compressor provided by an embodiment of the present invention.

[0042] Among them, 100, refrigerator; 10, frequency conversion controller; 10A, compressor cabin; 1, compressor; 2, evaporator; 3, capillary tube; 4, condenser; 5, bottom cooling fan; 6, evaporating dish. DETAILED DESCRIPTION

[0043] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. All other embodiments obtained by ordinary technicians in this field based on the embodiments of the present invention without making any creative efforts shall fall within the scope of protection of the present invention.

[0044] In the description of this application, it should be understood that the terms "center", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", etc., indicating the orientation or position relationship, are based on the orientation or position relationship shown in the accompanying drawings, and are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on this application.

[0045] The terms "first" and "second" are used for descriptive purposes only and should not be understood to indicate or imply relative importance or implicitly specify the number of the technical features indicated. Therefore, features specified as "first" and "second" may explicitly or implicitly include one or more of such features. In the description of this application, unless otherwise specified, "plurality" means two or more.

[0046] In the description of this application, it should be noted that, unless otherwise expressly specified or limited, the terms "mounted," "connected," and "connected" should be understood broadly. For example, they may refer to fixed, detachable, or integral connections; mechanical or electrical connections; direct or indirect connections through an intermediate medium; and internal communication between two components. Those skilled in the art will understand the specific meanings of the above terms in this application based on the specific circumstances.

[0047] See also Figure 1 , Figure 1 The figure below is a schematic diagram of the external structure of a refrigerator 100 provided in an embodiment of the present invention. The refrigerator 100 of this embodiment is approximately rectangular in shape and includes a housing defining a storage space and multiple doors disposed at the housing opening. The doors include a door shell located on the outside of the housing, a door liner located on the inside of the housing, an upper end cover, a lower end cover, and an insulation layer located between the door shell, the door liner, the upper end cover, and the lower end cover. Typically, the insulation layer is filled with foam. The housing is provided with a chamber, which includes a component storage cavity for accommodating refrigerator components, such as a compressor compartment, and storage space for food and the like.

[0048] See also Figure 2 , Figure 2 This is a schematic diagram of the internal structure of a refrigerator provided by an embodiment of the present invention. The storage space can be divided into multiple storage rooms. The storage rooms can be configured as refrigerators and freezers according to different uses. They can also include variable temperature rooms, vacuum drawers, moisturizing drawers, etc. Each storage room corresponds to one or more doors, such as Figure 2 The upper storage compartment has a double-door body. The door can be pivotally mounted at the opening of the refrigerator body and can also be opened in a drawer-like manner to achieve drawer-style storage. The refrigerator door is equipped with a display screen for displaying prompt information and receiving user touch operations.

[0049] See also Figure 3 , Figure 3The structural diagram of the refrigeration system in the refrigerator provided by the embodiment of the present invention, the refrigeration system includes a compressor 1, an evaporator 2, a drying filter (not shown in the figure), a capillary tube 3, a condenser 4 and a gas-liquid separator (not shown in the figure). The working process of the refrigeration system includes a compression process, a condensation process, a throttling process and an evaporation process. The compression process is: plug in the power cord of the refrigerator, when the contacts of the thermostat are connected, the compressor 1 starts to work, the low-temperature, low-pressure refrigerant is sucked into the compressor 1, and is compressed into a high-temperature, high-pressure superheated gas in the cylinder of the compressor 1 and then discharged into the condenser 4; the condensation process is: the high-temperature, high-pressure refrigerant gas dissipates heat through the condenser 4, the temperature continues to drop, and is gradually cooled to a saturated vapor of normal temperature and high pressure, and is further cooled to a saturated liquid, and the temperature no longer drops. The temperature at this time is called the condensation temperature, and the pressure of the refrigerant remains almost unchanged during the entire condensation process; The flow process is as follows: the saturated refrigerant liquid after condensation is filtered out of moisture and impurities by the drying filter and then flows into the capillary tube 3, through which the refrigerant is throttled and reduced in pressure to become wet steam at room temperature and low pressure; the evaporation process is as follows: the wet steam at room temperature and low pressure begins to absorb heat and vaporize in the evaporator 2, which not only reduces the temperature of the evaporator 2 and its surroundings, but also turns the refrigerant into a low-temperature and low-pressure gas. The refrigerant coming out of the evaporator 2 passes through the gas-liquid separator and returns to the compressor 1 again, repeating the above process to transfer the heat in the refrigerator to the air outside the box, thereby achieving the purpose of refrigeration.

[0050] See also Figure 4 , Figure 4This is a schematic diagram of the structure of a compressor compartment 10A according to an embodiment of the present invention. The compressor compartment 10A is equipped with a compressor 1, a condenser 4, a bottom cooling fan 5, and an evaporation dish 6. The evaporation dish 6 is used to receive defrost water. Specifically, the evaporation dish 6 receives defrost water from the freezer compartment and / or from the evaporator 2 during defrost. The evaporation dish 6 is fixed to the bottom wall of the compressor compartment 10A and is a box-like structure with an open top. The evaporation dish 6 comprises a horizontally arranged bottom plate and side panels extending upward from the edges of the bottom plate. The side panels are arranged around and interlock with each other, and the bottom plate is enclosed by the edges of the side panels, forming a box-like structure with an open top. The condenser 4 is arranged vertically, with its top end abutting the top surface of the compressor compartment 10A. This ensures that the condenser 4 can be installed within the compressor compartment 10A while minimizing the height of the compressor compartment 10A and thus increasing the storage compartment volume. The condenser 4 and the compressor 1 are spaced apart in the left-right direction. The bottom plate of the evaporating dish 6 is formed with protruding fixing posts, and the bottom end of the condenser 4 is fixed to the fixing posts directly or via connectors, so that the condenser 4 is fixed within the evaporating dish 6 and the bottom end of the condenser 4 is higher than the level of the defrost water in the evaporating dish 6. The refrigerator 100 is also equipped with a bottom cooling fan 5 for heat dissipation. A through hole (not shown) is provided on the side of the compressor compartment 10A facing the bottom cooling fan 5. The refrigerator 100 is provided with an exhaust vent for the outlet of the bottom cooling fan 5. In this embodiment, the bottom cooling fan 5 is a centrifugal fan. The left and right sides of the centrifugal fan are respectively attached to the compressor compartment 10A. The centrifugal fan inlet is provided in the through hole of the compressor compartment 10A, so that air in the compressor compartment 10A is discharged from the compressor compartment 10A through the centrifugal fan inlet.

[0051] See also Figure 5 , Figure 5This is a schematic diagram of the connection between the frequency conversion controller 10 and the compressor 1 provided in an embodiment of the present invention. The frequency conversion controller 10 is provided with a main control module MCU11 and a PID module 12. The MCU11 is used to collect the operating parameters of the compressor 1, such as real-time speed and electrical parameters. Based on these operating parameters, the operating status of the compressor 1 can be monitored, and timely warnings can be issued when the compressor 1 fails. The MCU11 can also control the startup and shutdown of the compressor 1. The MCU11 can then process and calculate the collected data, such as calculating the output power based on the electrical parameters of the motor in the frequency conversion controller 10. The MCU11 inputs the calculated data into the PID module 12 for PID control. Since the temperature of the power devices (such as the MCU) on the frequency conversion controller 10 will increase over time after reaching a certain power output, and will become higher and higher. If the temperature exceeds the limit, the power devices will be damaged. To reduce the temperature increase, after the frequency conversion controller 10 reaches a certain power output, the frequency conversion controller 10 is kept at a constant power output through the PID control link to avoid the problem of power device temperature increase. In addition, the optimal power reference value (the corresponding value after each frequency conversion controller hardware is determined) is used as the target power and compared with the actual calculated output power. The PID adjustment method is used to adjust the compressor operating speed to achieve precise speed control.

[0052] Specifically, the frequency conversion controller is configured to: obtain the electrical parameters of the motor in the frequency conversion controller, and calculate the output power based on the electrical parameters and preset frequency conversion characteristic parameters; when the output power does not match the preset target power, use the output power as the input of the PID module, and output the reference speed to the compressor through PID adjustment, so that the compressor runs according to the reference speed.

[0053] For example, see Figure 6 , Figure 6 This is the first workflow diagram of the variable frequency controller in the refrigerator provided by an embodiment of the present invention. The variable frequency controller is configured to execute steps S11 to S16. After the compressor is started, the variable frequency controller begins to obtain the electrical parameters of the motor, and then calculates the output power of the variable frequency controller based on the electrical parameters and preset frequency conversion characteristic parameters. Since each variable frequency controller has its optimal target power pre-stored, the output power can be compared with the target power, and the output power is input into the PID module for proportional, integral, and differential control, so that the output power of the variable frequency controller matches the target power. When the output power matches the target power, the reference speed of the motor is output based on this output power, so that the compressor operates at the reference speed.

[0054] Exemplarily, the electrical parameters include a q-axis current measurement value, a q-axis voltage measurement value, a d-axis current measurement value, and a d-axis voltage measurement value. Figure 7 , Figure 7 This is a schematic diagram of the PID control link provided by an embodiment of the present invention. After power calculation is performed based on the q-axis current measurement value, the q-axis voltage measurement value, the d-axis current measurement value, and the d-axis voltage measurement value, the output power P of the frequency conversion controller is obtained. This output power P is then compared with the target power Pmax, and the comparison result is input into the PID module for PID control, and then the reference speed is output.

[0055] It's worth noting that in the early development of motor drive speed control systems, DC drives enabled stepless speed regulation to achieve superior motor comfort. To achieve this same effect with AC speed control drives, frequency converters emerged. Frequency converter designers shifted the concept of electric drive from three-phase asynchronous motors to DC motors, achieving this through "decoupling" the d-axis and q-axis. Typically, DC motors control their rotor current and field current during drive. In frequency converter AC speed control systems, the "q-axis" corresponds to the DC motor's rotor electrical specifications, while the "d-axis" corresponds to the DC motor's field electrical specifications. The q-axis is not the motor's axis, but a mathematical coordinate axis that rotates synchronously with the rotor. This is equivalent to establishing a coordinate system on the motor rotor, transforming the motor's mathematical model into this coordinate system. The rotor magnetic field is oriented along the d-axis, and the direction perpendicular to the rotor magnetic field is the q-axis.

[0056] Specifically, the output power is calculated based on the electrical parameters and the preset frequency conversion characteristic parameters, including: calculating the product of the q-axis current measurement value and the q-axis voltage measurement value to obtain the q-axis power; calculating the product of the d-axis current measurement value and the d-axis voltage measurement value to obtain the d-axis power; calculating the power sum of the q-axis power and the d-axis power and the product of the frequency conversion characteristic parameters to obtain the output power.

[0057] For example, see Figure 8 , Figure 8 This is a second working flow diagram of the frequency conversion controller in the refrigerator provided by an embodiment of the present invention, wherein step S13 specifically includes steps S131 to S133. The output power calculation process satisfies the following formula:

[0058] P = K*(Iq*Uq+Id*Ud);

[0059] Among them, P is the output power; K is the frequency conversion characteristic parameter, which is a preset value and can be pre-set according to the model of different frequency conversion controllers; Iq is the q-axis current measurement value; Uq is the q-axis voltage measurement value; Id is the d-axis current measurement value; Ud is the d-axis voltage measurement value.

[0060] Specifically, the frequency conversion controller is further configured to: calculate the back electromotive force of the motor; and perform magnetic weakening control on the motor when the back electromotive force generated by the motor is greater than the bus voltage.

[0061] For example, in traditional motor control methods, the motor magnetic field strength will always be maintained at a high level, which will cause energy waste and increase the motor temperature, and will also reduce the motor's accuracy and life. The weak magnetic control algorithm can allow the motor to operate in a low magnetic field, reduce energy loss and motor temperature, and improve the efficiency and accuracy of the motor. By adjusting the motor's current and magnetic field strength, the motor can still maintain a stable speed and load carrying capacity under a low magnetic field. Specifically, the weak magnetic control algorithm can monitor the motor's magnetic field strength in real time and adjust the motor's current and magnetic field strength in time by estimating the motor's back electromotive force value, flux observer, predictive control, and model reference adaptive control. In this way, the motor can maintain stable operation under a low magnetic field, thereby achieving energy saving and consumption reduction, improving accuracy and extending the motor's life. The frequency conversion controller monitors the motor speed in real time. When the back electromotive force generated by the motor speed is greater than the bus voltage, the rotor magnetic field is weakened to obtain a higher speed.

[0062] See also Figure 9 , Figure 9 This is a schematic diagram of the FOC (Field-Oriented Control) framework of the motor in the variable frequency controller provided by an embodiment of the present invention. FOC, namely field-oriented control or vector control, is an advanced control technology in the field of motor control and one of the more advanced motor control methods currently available. The working principle of FOC is to control the current vector of the motor in the direction of the stator electromagnetic field of the motor so that the direction of the motor torque is consistent with the direction of the rotor magnetic field, thereby ensuring that the rotational torque output by the motor is maximized and the operating efficiency and performance are optimized. The FOC control method regards the magnetic field of the rotor as a rotating vector and controls the magnetic field of the motor by counter-rotating a fixed vector of the same frequency, thereby achieving control of the motor.

[0063] Exemplarily, after the PID module outputs the reference speed, PI control is performed on the q-axis electrical parameters, and field weakening control is performed on the d-axis electrical parameters. PI control requires the addition of a q-axis reference current Iqref, while field weakening control requires the addition of a d-axis reference current Idref. After PI control, a q-axis voltage Uq is output, and after field weakening control, a d-axis voltage Ud is output. Then, an inverse Park transform is performed on the q-axis voltage Uq and the d-axis voltage Ud. In the FOC framework, the Park transform converts the α and β coordinate systems into the d and q coordinate systems; the inverse Park transform converts the d and q coordinate systems into the α and β coordinate systems; and the Clark transform converts the a, b, and c coordinate systems into the α and β coordinate systems. The presence of the α and β axes allows the three-phase currents (Ia, Ib, and Ic) to be represented by two variables (Iα and Iβ), and the three-phase voltages (Ua, Ub, and Uc) to be represented by two variables (Vα and Vβ). With one of the variables missing, α and β are perpendicular and orthogonal, but Iα and Iβ remain sinusoidal, making PID control difficult. Therefore, transformations are required to convert these into linear quantities. This is the task of the Park and inverse Park transforms. The inverse Park transform converts Ud and Uq into Vα and Vβ after PI control; the Park transform converts Iα and Iβ into Id and Iq after acquiring the motor current and passing them to the PI controller. It can be seen from the FOC diagram that Park and Anti-Park exist for PI control.

[0064] Specifically, the variable frequency controller also includes a three-phase bridge, which is connected to the PID module and the compressor. The three-phase bridge comprises a bridge circuit composed of several insulated gate bipolar transistors (IGBTs). R is a sampling resistor that can sample Ia, Ib, and Ic. The three-phase bridge comprises a bridge circuit composed of six insulated gate bipolar transistors (IGBTs).

[0065] For example, the electrical parameters are subjected to inverse Park transformation and then SVW modulation before being input into the three-phase bridge. SVPWM (Space Vector Pulse Width Modulation), also known as space vector pulse width modulation, is abbreviated as SVW. SVPWM is a pulse width modulation wave generated by a specific switching mode composed of six power switching elements of a three-phase power inverter, which can make the output current waveform as close to the ideal sinusoidal waveform as possible. Space voltage vector PWM is different from traditional sinusoidal PWM. It starts from the overall effect of the three-phase output voltage and focuses on how to make the motor obtain an ideal circular magnetic flux trajectory. Compared with SPWM, SVPWM technology has a smaller harmonic component in the winding current waveform, which reduces the motor torque pulsation and makes the rotating magnetic field closer to a circle. It also greatly improves the utilization rate of the DC bus voltage and is easier to digitize.

[0066] Compared with the prior art, the refrigerator disclosed in the present invention adds a PID control link in the frequency conversion controller. Without adding heat dissipation devices, the PID control method is used to realize the heat dissipation process of the frequency conversion controller. The control accuracy is high and the deviation is small, which can avoid the phenomenon of ultra-high temperature failure of the power devices on the frequency conversion controller.

[0067] See also Figure 10 , Figure 10 1 is a flow chart of a method for controlling the speed of a refrigerator compressor provided by an embodiment of the present invention. The method is implemented by a variable frequency controller in the refrigerator. The method includes:

[0068] S1. Obtain electrical parameters of the motor in the frequency conversion controller, and calculate the output power based on the electrical parameters and preset frequency conversion characteristic parameters;

[0069] S2. When the output power does not match the preset target power, the output power is used as the input of the PID module, and a reference speed is output to the compressor through PID regulation, so that the compressor operates at the reference speed.

[0070] Specifically, the electrical parameters include a q-axis current measurement value, a q-axis voltage measurement value, a d-axis current measurement value, and a d-axis voltage measurement value.

[0071] Specifically, the output power is calculated based on the electrical parameters and the preset frequency conversion characteristic parameters, including: calculating the product of the q-axis current measurement value and the q-axis voltage measurement value to obtain the q-axis power; calculating the product of the d-axis current measurement value and the d-axis voltage measurement value to obtain the d-axis power; calculating the power sum of the q-axis power and the d-axis power and the product of the frequency conversion characteristic parameters to obtain the output power.

[0072] Specifically, the method further includes: calculating the back electromotive force of the motor; and performing magnetic weakening control on the motor when the back electromotive force generated by the motor is greater than the bus voltage.

[0073] It is worth noting that the specific working process of the refrigerator compressor speed control method described in the embodiment of the present invention can refer to the working process of the controller described in the above embodiment, and will not be repeated here.

[0074] Compared with the existing technology, the refrigerator compressor speed control method disclosed in the present invention adds a PID control link in the frequency conversion controller. Without adding heat dissipation devices, the PID control method is used to realize the heat dissipation process of the frequency conversion controller. The control accuracy is high and the deviation is small, which can avoid the phenomenon of ultra-high temperature failure of the power devices on the frequency conversion controller.

[0075] The above is a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principles of the present invention. These improvements and modifications are also considered to be within the scope of protection of the present invention.

Claims

1. A refrigerator, characterized in that: include: a box body, in which at least one storage chamber is formed; A door is provided at the opening of the storage chamber and is used to open and close the storage chamber; a compressor, disposed within the housing, for providing power for a refrigeration cycle of the refrigerator; A frequency conversion controller is provided in the housing. The frequency conversion controller is provided with a PID module. The frequency conversion controller is configured as follows: Obtaining electrical parameters of the motor in the frequency conversion controller, and calculating output power based on the electrical parameters and preset frequency conversion characteristic parameters; When the output power does not match the preset target power, the output power is used as the input of the PID module, and a reference speed is output to the compressor through PID regulation, so that the compressor runs at the reference speed.

2. The refrigerator according to claim 1, wherein The electrical parameters include a q-axis current measurement value, a q-axis voltage measurement value, a d-axis current measurement value, and a d-axis voltage measurement value.

3. The refrigerator according to claim 2, wherein: The calculating the output power according to the electrical parameters and the preset frequency conversion characteristic parameters includes: Calculating the product of the q-axis current measurement value and the q-axis voltage measurement value to obtain the q-axis power; Calculating the product of the d-axis current measurement value and the d-axis voltage measurement value to obtain the d-axis power; The output power is obtained by calculating the product of the power sum of the q-axis power and the d-axis power and the frequency conversion characteristic parameter.

4. The refrigerator according to claim 1, wherein The frequency conversion controller is further configured to: calculating the back electromotive force of the motor; When the back electromotive force generated by the motor is greater than the bus voltage, the motor is subjected to flux weakening control.

5. The refrigerator according to claim 1, wherein The frequency conversion controller is further provided with a three-phase bridge, which is respectively connected to the PID module and the compressor. The three-phase bridge includes a bridge circuit composed of a plurality of insulated gate bipolar transistors.

6. A refrigerator compressor speed control method, characterized in that: include: Obtaining electrical parameters of the motor in the frequency conversion controller, and calculating the output power based on the electrical parameters and preset frequency conversion characteristic parameters; When the output power does not match the preset target power, the output power is used as the input of the PID module, and a reference speed is output to the compressor through PID regulation, so that the compressor runs at the reference speed.

7. The refrigerator compressor speed control method according to claim 6, wherein: The electrical parameters include a q-axis current measurement value, a q-axis voltage measurement value, a d-axis current measurement value, and a d-axis voltage measurement value.

8. The refrigerator compressor speed control method according to claim 7, wherein: The calculating the output power according to the electrical parameters and the preset frequency conversion characteristic parameters includes: Calculating the product of the q-axis current measurement value and the q-axis voltage measurement value to obtain the q-axis power; Calculating the product of the d-axis current measurement value and the d-axis voltage measurement value to obtain the d-axis power; The output power is obtained by calculating the product of the power sum of the q-axis power and the d-axis power and the frequency conversion characteristic parameter.

9. The refrigerator compressor speed control method according to claim 6, wherein: The method further comprises: calculating the back electromotive force of the motor; When the back electromotive force generated by the motor is greater than the bus voltage, the motor is subjected to flux weakening control.

Images