Power supply control method, motor power supply circuit and motor power supply device

Abstract

The present invention proposes a power supply control method, a motor power supply circuit and a motor power supply device, wherein the power supply control method is applied to the motor power supply circuit, the motor power supply circuit includes a rectifier circuit, a boost circuit, a bidirectional DC conversion circuit and an inverter circuit. When the light intensity is high, the output voltage of the photovoltaic module is high, and the module switches to a first working mode and controls the boost circuit and the inverter circuit to perform power supply. When the light intensity is low, the output voltage of the photovoltaic module is low, and the module switches to a second working mode, starts the rectifier circuit and / or the bidirectional DC conversion circuit and the inverter circuit, and is powered by AC power or a battery module, thereby achieving stable power supply to the motor under different light intensities and meeting the power supply requirements of the load.

Description

Technical Field

[0001] The present invention belongs to the technical field of motor drive, and in particular relates to a power supply control method, a motor power supply circuit and a motor power supply device. Background Art

[0002] Solar photovoltaic power generation is a green and clean energy with the characteristics of renewable utilization, green environmental protection, and high conversion efficiency. It is widely used in daily life.

[0003] Photovoltaic panels output direct current, which can power motor loads such as pumps, fans, and compressors. However, the output power of photovoltaic panels varies with light intensity, making it difficult to stably supply the loads when light intensity fluctuates. Summary of the Invention

[0004] The purpose of the present invention is to provide a power supply control method, aiming to solve the problem that traditional photovoltaic panels cannot provide stable power supply.

[0005] A first aspect of an embodiment of the present invention provides a power supply control method for controlling a motor power supply circuit, wherein the motor power supply circuit includes a rectifier circuit, a boost circuit, a bidirectional DC conversion circuit, and an inverter circuit, wherein an input end of the inverter circuit is respectively connected to an output end of the rectifier circuit, an output end of the boost circuit, and a first end of the bidirectional DC conversion circuit; an input end of the rectifier circuit is connected to mains power; an input end of the boost circuit is connected to a photovoltaic module; a second end of the bidirectional DC conversion circuit is connected to a battery module; and an output end of the inverter circuit is connected to a motor;

[0006] The power supply control method includes:

[0007] Obtaining the output voltage of the photovoltaic module;

[0008] When the output voltage is greater than a first preset voltage, switching to a first operating mode, wherein the first operating mode is: shutting down the rectifier circuit and the bidirectional DC conversion circuit, and starting the boost circuit to perform boost conversion and starting the inverter circuit to perform inverter conversion;

[0009] When the output voltage is less than the first preset voltage, the second working mode is switched to: shutting down the boost circuit, starting the rectifier circuit to perform rectification and / or starting the bidirectional DC conversion circuit to perform battery discharge, and starting the inverter circuit to perform inverter conversion.

[0010] Optionally, the first working mode further includes:

[0011] Obtaining the open-circuit voltage of the photovoltaic module and starting the boost circuit to perform boost conversion;

[0012] The output voltage of the photovoltaic module is obtained, and the duty cycle of the control signal of the boost circuit is adjusted based on the output voltage.

[0013] Optionally, obtaining the output voltage of the photovoltaic module and adjusting the duty cycle of the control signal of the boost circuit based on the output voltage includes:

[0014] When the output voltage of the photovoltaic module is greater than 0.78 times the open circuit voltage, reducing the duty cycle of the switch control signal of the boost circuit;

[0015] When the output voltage of the photovoltaic module is less than 0.78 times the open circuit voltage, increasing the duty cycle of the switch control signal of the boost circuit;

[0016] When the output voltage of the photovoltaic module is equal to 0.78 times the open circuit voltage, the duty cycle of the switch control signal of the boost circuit is maintained.

[0017] Optionally, the first working mode further includes:

[0018] Obtaining the output power change rate and the output voltage change rate of the photovoltaic module per unit time and performing ratio calculation to obtain a first ratio;

[0019] The duty cycle and the change rate of the switch control signal of the boost circuit are adjusted according to the first ratio.

[0020] Optionally, adjusting the duty cycle and the change rate of the switch control signal of the boost circuit according to the first ratio includes:

[0021] When the first ratio is greater than zero, increasing the duty cycle of the switch control signal;

[0022] When the first ratio is less than zero, reducing the duty cycle of the switch control signal;

[0023] When the first ratio is equal to zero, maintaining the duty cycle of the switch control signal;

[0024] When the absolute value of the first ratio is greater than a preset value, increasing the rate of change of the duty cycle of the switch control signal output to the boost circuit;

[0025] When the absolute value of the first ratio is less than a preset value, the change rate of the duty cycle of the switch control signal is reduced.

[0026] Optionally, the power supply control method further includes:

[0027] Obtaining the load of the motor and comparing the load with a preset load value;

[0028] When the load is less than a preset load value, reducing the excitation flux of the motor to reduce the excitation current of the motor;

[0029] When the load is greater than a preset load, the excitation flux of the motor is increased to a rated flux to increase the excitation current of the motor.

[0030] Optionally, in the second working mode, starting the rectifier circuit to perform rectification and / or starting the bidirectional DC conversion circuit to perform battery discharge includes:

[0031] Obtaining the terminal voltage of the battery module;

[0032] When the terminal voltage of the battery module is greater than a second preset voltage, the boost circuit and the rectifier circuit are turned off, and the bidirectional DC conversion circuit is started to perform battery discharge operation;

[0033] When the terminal voltage of the battery module is lower than a second preset voltage, the boost circuit and the bidirectional DC conversion circuit are turned off, and the rectifier circuit is started to perform rectification and output operation.

[0034] Optionally, the first working mode further includes:

[0035] detecting the terminal voltage of the battery module;

[0036] When the terminal voltage of the battery module is less than a third preset voltage, the bidirectional DC conversion circuit is turned on to perform battery charging, and the third preset voltage is less than or equal to the second preset voltage.

[0037] Optionally, the second working mode further includes:

[0038] When the terminal voltage of the battery module is lower than the third preset voltage, the bidirectional DC conversion circuit is turned on to perform battery charging.

[0039] A second aspect of an embodiment of the present invention provides a motor power supply circuit, comprising a rectifier circuit, a boost circuit, a bidirectional DC conversion circuit, an inverter circuit, and a control circuit, wherein the input end of the inverter circuit is respectively connected to the output end of the rectifier circuit, the output end of the boost circuit, and the first end of the bidirectional DC conversion circuit; the input end of the rectifier circuit is connected to the mains, the input end of the boost circuit is connected to a photovoltaic module, the second end of the bidirectional DC conversion circuit is connected to a battery module, the output end of the inverter circuit is connected to a motor, and the control circuit is respectively connected to the rectifier circuit, the boost circuit, the bidirectional DC conversion circuit, and the inverter circuit;

[0040] The control circuit is used to implement the steps of the power supply control method described above.

[0041] A third aspect of an embodiment of the present invention provides a motor power supply device, comprising a battery module, a photovoltaic module and the motor power supply circuit as described above, wherein the motor power supply circuit is respectively connected to the mains, the battery module, the photovoltaic module and the motor.

[0042] The beneficial effects of the embodiments of the present invention compared with the prior art are: the above-mentioned power supply control method is applied to the motor power supply circuit, the motor power supply circuit includes a rectifier circuit, a boost circuit, a bidirectional DC conversion circuit and an inverter circuit. When the light intensity is high, the output voltage of the photovoltaic module is high, and it switches to the first working mode and controls the boost circuit and the inverter circuit to perform power supply work; when the light intensity is low, the output voltage of the photovoltaic module is low, and it switches to the second working mode, starts the rectifier circuit and / or the bidirectional DC conversion circuit and the inverter circuit, and is powered by AC power or a battery module, thereby achieving stable power supply for the motor under different light intensities and meeting the power supply requirements of the load. BRIEF DESCRIPTION OF THE DRAWINGS

[0043] Figure 1 A schematic diagram of a first structure of a motor power supply circuit and a motor power supply device provided in an embodiment of the present invention;

[0044] Figure 2 A schematic diagram of a first flow chart of a power supply control method provided in an embodiment of the present invention;

[0045] Figure 3 for Figure 1 A first specific flow chart of step S200 in the power supply control method shown;

[0046] Figure 4 A schematic diagram of a curve showing the output voltage and power of a boost circuit provided in an embodiment of the present invention;

[0047] Figure 5 for Figure 4 The specific flow chart of step S220 in the power supply control method shown;

[0048] Figure 6 for Figure 1 A second specific flow chart of step S200 in the power supply control method shown;

[0049] Figure 7 for Figure 6 The specific flow chart of step S220 in the power supply control method shown;

[0050] Figure 8 for Figure 1 A first specific flow chart of step S300 in the power supply control method shown;

[0051] Figure 9 for Figure 1 Three specific flow charts of step S200 in the power supply control method shown;

[0052] Figure 10 for Figure 1 A second specific flow chart of step S300 in the power supply control method shown;

[0053] Figure 11 A second flow chart of the power supply control method provided in an embodiment of the present invention;

[0054] Figure 12 This is a second structural diagram of the motor power supply circuit and the motor power supply device provided in an embodiment of the present invention. DETAILED DESCRIPTION

[0055] In order to make the technical problems, technical solutions and beneficial effects to be solved by the present invention more clearly understood, the present invention is further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention.

[0056] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of the technical features being referred to. Thus, a feature identified as "first" or "second" may explicitly or implicitly include one or more of the features. In the description of the present invention, "plurality" means two or more, unless otherwise specifically defined.

[0057] A first aspect of an embodiment of the present invention proposes a power supply control method for controlling a motor power supply circuit 100, wherein the motor power supply circuit 100 includes a rectifier circuit 10, a boost circuit 20, a bidirectional DC conversion circuit 30 and an inverter circuit 40, wherein the input end of the inverter circuit 40 is respectively connected to the output end of the rectifier circuit 10, the output end of the boost circuit 20 and the first end of the bidirectional DC conversion circuit 30, the input end of the rectifier circuit 10 is connected to the mains 200, the input end of the boost circuit 20 is connected to the photovoltaic module 300, the second end of the bidirectional DC conversion circuit 30 is connected to the battery module 400, and the output end of the inverter circuit 40 is connected to the motor 500.

[0058] The rectifier circuit 10 is used to rectify the AC power 200 at startup and convert it into a DC power supply. The boost circuit 20 is used to boost the output voltage of the photovoltaic module 300 at startup, and the DC power output by the boost circuit 20 has the same voltage as the DC power output by the rectifier circuit 10. The bidirectional DC conversion circuit 30 can be used to achieve bidirectional DC conversion, including when the battery module 400 is discharged, the discharge voltage of the battery module 400 is converted from DC to DC, and the output voltage of the bidirectional DC conversion circuit 30 is equal to the output voltage of the boost circuit 20, and when the battery module 400 is charged, the bidirectional DC conversion circuit 30 can convert the output voltage of the boost circuit 20 or the output voltage of the rectifier circuit 10 from DC to DC, and output a charging power supply to charge the battery module 400.

[0059] Among them, the photovoltaic module 300 can adopt photovoltaic panels and corresponding energy storage inverters, junction boxes and other structures, the battery module 400 can be composed of multiple single cells connected in series and parallel, the rectifier circuit 10 can include a corresponding rectifier bridge and a switching circuit for controlling the on and off of the rectifier circuit 10, etc., the boost circuit 20 can adopt a boost circuit or a boost converter and other structures, and the bidirectional DC conversion circuit 30 can adopt a bidirectional DC / DC converter or a corresponding DC conversion circuit and other structures.

[0060] The inverter circuit 40 is used to perform inversion conversion between the input end and the output end, and output AC power to the motor 500. The motor 500 can be a water pump motor, a fan motor, a compressor motor, etc. The inverter circuit 40 can adopt a corresponding inverter bridge, inverter, or other circuit structure.

[0061] In order to achieve stable operation of the motor 500, in an optional embodiment, as shown in FIG. Figure 2 As shown, in this embodiment, the power supply control method includes:

[0062] S100, obtaining the output voltage of the photovoltaic module 300;

[0063] S200, when the output voltage is greater than the first preset voltage, switching to the first operating mode, the first operating mode is: shutting down the rectifier circuit 10 and the bidirectional DC conversion circuit 30, and starting the boost circuit 20 to perform boost conversion and starting the inverter circuit 40 to perform inverter conversion;

[0064] S300. When the output voltage is less than the first preset voltage, switch to the second working mode. The second working mode is: shut down the boost circuit 20, and start the rectifier circuit 10 to perform rectification work and / or start the bidirectional DC conversion circuit 30 to perform battery discharge work, and start the inverter circuit 40 to perform inverter conversion work.

[0065] In this embodiment, the magnitude of the output voltage of the photovoltaic module 300 represents the magnitude of the light intensity. When the output voltage is large, it indicates that the current light intensity is large, and when the output voltage is small, it indicates that the current light intensity is low.

[0066] When the light intensity is high, the current photovoltaic module 300 can complete the load power supply work. For this reason, when it is detected that the output voltage is greater than the first preset voltage, it indicates that the current light intensity is high. At this time, the power supply control circuit 50 is controlled to switch to the first working mode. In the first working mode, the rectifier circuit 10 and the bidirectional DC conversion circuit 30 are controlled to be turned off, and the boost circuit 20 is started. The boost circuit 20 performs a boost conversion on the output voltage of the photovoltaic module 300, and outputs a first power supply of DC power to the inverter circuit 40. The inverter circuit 40 is started synchronously to convert the first power supply output by the boost circuit 20 into AC power and drive the motor 500 to work.

[0067] In addition, during the operation of the boost circuit 20, in order to achieve maximum power output of the photovoltaic module 300 and improve power output efficiency, in an optional embodiment, as shown in FIG. Figure 3 As shown, the first working mode also includes:

[0068] S210, obtaining the open-circuit voltage of the photovoltaic module 300, and starting the boost circuit 20 to perform boost conversion;

[0069] S220 , obtaining the output voltage of the photovoltaic module 300 , and adjusting the duty cycle of the control signal of the boost circuit 20 based on the output voltage.

[0070] In this embodiment, the power supply control method also uses a constant voltage start to implement maximum power tracking control, that is, when the light conditions change, such as Figure 4 As shown, the maximum power Pm of the photovoltaic module 300 is around 0.78 times of its open circuit voltage. By adopting the constant voltage method, the output voltage of the photovoltaic module 300 is controlled at 0.78 times of its open circuit voltage, thereby obtaining the maximum power Pm.

[0071] Specifically, if Figure 5 As shown, step S220 includes:

[0072] S221, when the output voltage of the photovoltaic module 300 is greater than 0.78 times the open circuit voltage, reducing the duty cycle of the switch control signal of the boost circuit 20;

[0073] S222, when the output voltage of the photovoltaic module 300 is less than 0.78 times the open circuit voltage, increasing the duty cycle of the switch control signal of the boost circuit 20;

[0074] S223 , when the output voltage of the photovoltaic module 300 is equal to 0.78 times the open-circuit voltage, maintaining the duty cycle of the switch control signal of the boost circuit 20 .

[0075] When it is detected that the output voltage of the photovoltaic module 300 is greater than 0.78 times the open-circuit voltage, it indicates that the current operating point of the photovoltaic module 300 is to the right of the maximum power Pm. At this time, it is necessary to reduce the duty cycle of the switch control signal of the boost circuit 20 to reduce the output voltage of the photovoltaic module 300, so that the output voltage gradually approaches 0.78 times the open-circuit voltage, and the output power gradually approaches the maximum power Pm.

[0076] When it is detected that the output voltage of the photovoltaic module 300 is less than 0.78 times the open-circuit voltage, it indicates that the current operating point of the photovoltaic module 300 is on the left side of the maximum power Pm. At this time, it is necessary to increase the duty cycle of the switch control signal of the boost circuit 20 to increase the output voltage of the photovoltaic module 300, so that the output voltage gradually approaches 0.78 times the open-circuit voltage, and the output power gradually approaches the maximum power Pm.

[0077] And when it is detected that the output voltage of the photovoltaic module 300 is equal to 0.78 times the open-circuit voltage, it indicates that the current operating point of the boost circuit 20 is at the maximum power Pm. At this time, the duty cycle of the switch control signal is maintained, that is, the output voltage of the photovoltaic module 300 is maintained, so that the power of the photovoltaic module 300 is stabilized at the maximum power Pm.

[0078] In addition, the power supply control method also uses the incremental conductance method to achieve maximum power tracking control. Specifically, Figure 6 As shown, the first working mode also includes:

[0079] S230, obtaining the output power change rate and the output voltage change rate of the photovoltaic module 300 per unit time and performing ratio calculation to obtain a first ratio;

[0080] S240 , adjusting the rate of change of the duty cycle of the switch control signal of the boost circuit 20 according to the first ratio.

[0081] Among them, the incremental conductance method determines the ratio of the output power change rate of the boost circuit 20 to the output voltage change rate per unit time, that is, the size of the first ratio, and determines the output power adjustment direction and adjustment size of the photovoltaic module 300 by judging the size and positive and negative of the first ratio, thereby ensuring that the photovoltaic module 300 always operates at maximum power.

[0082] Specifically, if Figure 7 As shown, step S240 includes:

[0083] S241. When the first ratio is greater than zero, increase the duty cycle of the switch control signal;

[0084] S242, when the first ratio is less than zero, reducing the duty cycle of the switch control signal;

[0085] S243, when the first ratio is equal to zero, maintaining the duty cycle of the switch control signal;

[0086] S244: when the absolute value of the first ratio is greater than a preset value, increase the rate of change of the duty cycle of the switch control signal;

[0087] S245 : When the absolute value of the first ratio is less than a preset value, reduce the rate of change of the duty cycle of the switch control signal.

[0088] In this embodiment, the magnitude and change rate of the output voltage of the photovoltaic module 300 are adjusted by determining the magnitude of the first ratio, thereby improving the efficiency of changing the output power to Pm.

[0089] When it is detected that the first ratio is greater than zero, it indicates that the current operating point of the photovoltaic module 300 is on the left side of the maximum power Pm. At this time, it is necessary to increase the duty cycle of the switch control signal of the boost circuit 20 to increase the output voltage of the photovoltaic module 300 so that the output power gradually approaches the maximum power Pm.

[0090] When it is detected that the first ratio is less than zero, it indicates that the current operating point of the photovoltaic module 300 is to the right of the maximum power Pm. At this time, it is necessary to reduce the duty cycle of the switch control signal of the boost circuit 20 to reduce the output voltage of the photovoltaic module 300 so that the output power gradually approaches the maximum power Pm.

[0091] When it is detected that the first ratio is equal to zero, it indicates that the current operating point of the photovoltaic module 300 is at the maximum power Pm. At this time, it is necessary to maintain the duty cycle of the switch control signal of the boost circuit 20 to maintain the output voltage of the photovoltaic module 300 so that the output power is gradually maintained at the maximum power Pm.

[0092] When the absolute value of the first ratio is detected to be large, it indicates that the slope of the curve position of the current output voltage and output power is large, and the output voltage is far away from Vm. The rate of change of the output voltage can be increased to make it grow rapidly, that is, by increasing the rate of change of the duty cycle of the switch control signal of the boost circuit 20. The rate of change can be a growth rate or an attenuation rate. Correspondingly, the rate of change of the output voltage of the boost circuit 20 increases, so that the output power quickly approaches Pm.

[0093] Similarly, when it is detected that the absolute value of the first ratio is less than the preset voltage, it indicates that the slope of the curve position of the current output voltage and output power is small, close to the maximum power Pm, and the output power is close to the Vm corresponding to the maximum power. At this time, if a large change rate is used, there is a problem of overmodulation. For this reason, it is necessary to reduce the change rate of the output voltage, that is, by reducing the change rate of the duty cycle of the switching control signal of the boost circuit 20. The change rate can be a growth rate or an attenuation rate. Correspondingly, the change rate of the output voltage of the boost circuit 20 is reduced, so that the output power gradually approaches the maximum power Pm, and finally stabilizes at the maximum power Pm.

[0094] In addition, when the light intensity is low, the current photovoltaic module 300 cannot provide stable power supply. Therefore, when it is detected that the output voltage of the photovoltaic module 300 is less than the first preset voltage, it indicates that the current light intensity is low. At this time, the power supply control circuit 50 is controlled to switch to the second working mode. In the second working mode, the boost circuit 20 is controlled to be turned off, the boost circuit 20 stops the boosting work, and there is no first power supply output. Synchronously, the rectifier circuit 10 and / or the bidirectional DC conversion circuit 30 are controlled to start. The rectifier circuit 10 can rectify the AC power 200 and output the second power supply. The bidirectional DC conversion circuit 30 can convert the output voltage of the battery module 400 and output the third power supply, thereby realizing power supply of the battery module 400 or the AC power 200. The second power supply and / or the third power supply are output to the inverter circuit 40. The inverter circuit 40 converts the DC power on the DC bus into AC power and drives the motor 500 to work.

[0095] The power supply priorities of the mains 200 and the battery module 400 can be set according to different power supply requirements. In an optional embodiment, as shown in FIG. Figure 8 As shown, step S300 includes:

[0096] S310, obtaining the terminal voltage of the battery module 400;

[0097] S320: When the terminal voltage of the battery module 400 is greater than the second preset voltage, the boost circuit 20 and the rectifier circuit 10 are turned off, and the bidirectional DC conversion circuit 30 is started to perform battery discharge operation;

[0098] S330 , when the terminal voltage of the battery module 400 is lower than the second preset voltage, the boost circuit 20 and the bidirectional DC conversion circuit 30 are turned off, and the rectifier circuit 10 is started to perform rectification and output operation.

[0099] In this embodiment, the power supply priority of the battery module 400 is greater than the power supply priority of the AC power 200. When the light intensity is low, the terminal voltage of the battery module 400 is detected to determine whether the battery module 400 meets the power supply conditions. When it is detected that the terminal voltage of the battery module 400 is higher than the second preset voltage, it is determined that the power of the battery module 400 meets the power supply conditions. At this time, the boost circuit 20 and the rectifier circuit 10 are controlled to be turned off, and the bidirectional DC conversion circuit 30 is turned on. The bidirectional DC conversion circuit 30 converts the terminal voltage of the battery module 400 into DC-DC and outputs a third power supply to the inverter circuit 40. The inverter circuit 40 inverts and outputs AC power to the motor 500.

[0100] When it is detected that the terminal voltage of the battery module 400 is less than the second preset voltage, it indicates that the current power level of the battery module 400 is low and does not meet the power supply conditions, and it is necessary to switch to the AC power 200 for power supply. At this time, the boost circuit 20 and the bidirectional DC conversion circuit 30 are controlled to be turned off, and the rectifier circuit 10 is turned on. The rectifier circuit 10 rectifies and converts the AC power 200 and outputs the second power supply to the inverter circuit 40. The inverter circuit 40 inverts and outputs AC power to the motor 500.

[0101] In addition, when the light intensity is high and the voltage of the battery module 400 is low, in order to improve the power conversion efficiency and reduce energy loss, the battery module 400 can also be charged in the first working mode. In an optional embodiment, Figure 9 As shown, the first working mode also includes:

[0102] S250, detecting the terminal voltage of the battery module 400;

[0103] S260 , when the terminal voltage of the battery module 400 is less than a third preset voltage, turning on the bidirectional DC conversion circuit 30 to perform battery charging, and the third preset voltage is less than or equal to the second preset voltage.

[0104] In this embodiment, when in the first working mode, when it is detected that the voltage of the battery module 400 is less than the third preset voltage, it indicates that the power of the battery module 400 is low, and the third preset voltage and the second preset voltage may be equal to or less than the second preset voltage. At this time, the bidirectional DC conversion circuit 30 is controlled to perform battery charging, and the excess power output by the boost circuit 20 is output to the battery module 400 through the bidirectional DC conversion circuit 30 to charge the battery module 400.

[0105] Correspondingly, in the second working mode, when the mains 200 is selected for power supply, the battery can also be charged. In an optional embodiment, as shown in FIG. Figure 10 As shown, optionally, the second working mode also includes:

[0106] S340 , when the terminal voltage of the battery module 400 is lower than the third preset voltage, the bidirectional DC conversion circuit 30 is turned on to perform battery charging.

[0107] In this embodiment, when the AC power 200 is used and the battery module 400 has a low power level, the bidirectional DC conversion circuit 30 is turned on synchronously. At this time, the bidirectional DC conversion circuit 30 switches to a charging state and transmits excess power output by the rectifier circuit 10 to the battery module 400 to charge the battery module 400.

[0108] Furthermore, in order to improve the working efficiency of the motor 500, in an optional embodiment, as Figure 11 As shown, the power supply control method further includes:

[0109] S400, obtaining the load size of the motor 500, and comparing the load with a preset load value;

[0110] S500, when the load is less than a preset load value, reducing the excitation flux of the motor 500 to reduce the excitation current of the motor 500;

[0111] S600 : When the load is greater than the preset load, the excitation flux of the motor 500 is increased to the rated flux to increase the excitation current of the motor 500 .

[0112] In this embodiment, the power supply control method further obtains the load size of the motor 500 and adaptively adjusts the control mode of the motor 500 according to the load size, so that the motor 500 operates at the maximum efficiency point.

[0113] Specifically, the power supply control method detects the torque current of the motor 500 through the output end of the inverter circuit 40, thereby obtaining the load size of the motor 500, and compares the torque current with the torque current setting value, thereby realizing the comparison of the load with the preset load value. When the torque current is less than the torque current setting value, the comparison value is negative, the comparison value is PI-adjusted, and the excitation flux is proportionally limited according to the size of the comparison value. The larger the negative value of the comparison value, the larger the excitation flux limitation, and the smaller the negative value of the comparison value, the smaller the excitation flux limitation. The excitation flux after limitation changes, the output voltage of the inverter circuit 40 decreases, the output excitation current decreases accordingly, and the loss of the motor 500 is reduced, thereby effectively controlling the efficiency of the motor 500.

[0114] After the initial change in magnetic flux, the excitation current of the inverter circuit 40 and the corresponding changed excitation magnetic flux are also obtained in real time. The excitation magnetic flux detected in real time is compared with the adjusted excitation magnetic flux and PI adjustment is performed to change the magnitude of the excitation current so that the excitation magnetic flux is stabilized at the excitation magnetic flux after limiting.

[0115] When it is detected that the load of motor 500 becomes larger, the comparison value becomes smaller or zero. At this time, the excitation flux limit value is set to the rated value. At this time, the excitation flux of motor 500 is restored, and the output voltage of motor 500 is restored to the set value, thereby restoring the load capacity of motor 500.

[0116] It should be understood that the size of the serial numbers of the steps in the above embodiments does not mean the order of execution. The execution order of each process should be determined by its function and internal logic, and should not constitute any limitation on the implementation process of the embodiments of the present invention.

[0117] The beneficial effects of the embodiments of the present invention compared with the prior art are as follows: the above-mentioned power supply control method is applied to the motor power supply circuit 100, the motor power supply circuit 100 includes a rectifier circuit 10, a boost circuit 20, a bidirectional DC conversion circuit 30 and an inverter circuit 40. When the light intensity is high, the output voltage of the photovoltaic module 300 is high, and it switches to the first working mode and controls the boost circuit 20 and the inverter circuit 40 to perform power supply work; when the light intensity is low, the output voltage of the photovoltaic module 300 is low, and it switches to the second working mode, starts the rectifier circuit 10 and / or the bidirectional DC conversion circuit 30 and the inverter circuit 40, and is powered by the AC power 200 or the battery module 400, thereby achieving stable power supply for the motor 500 under different light intensities and meeting the power supply requirements of the load.

[0118] The second aspect of the embodiment of the present invention provides a motor power supply circuit 100, such as Figure 12 As shown, the motor power supply circuit 100 includes a rectifier circuit 10, a boost circuit 20, a bidirectional DC conversion circuit 30, an inverter circuit 40 and a control circuit 50. The input end of the inverter circuit 40 is respectively connected to the output end of the rectifier circuit 10, the output end of the boost circuit 20 and the first end of the bidirectional DC conversion circuit 30, the input end of the rectifier circuit 10 is connected to the mains 200, the input end of the boost circuit 20 is connected to the photovoltaic module 300, the second end of the bidirectional DC conversion circuit 30 is connected to the battery module 400, the output end of the inverter circuit 40 is connected to the motor 500, and the control circuit 50 is respectively connected to the rectifier circuit 10, the boost circuit 20, the bidirectional DC conversion circuit 30 and the inverter circuit 40.

[0119] The rectifier circuit 10 is used to rectify the AC power 200 at startup and convert it into a DC power supply. The boost circuit 20 is used to boost the output voltage of the photovoltaic module 300 at startup, and the DC power output by the boost circuit 20 has the same voltage as the DC power output by the rectifier circuit 10. The bidirectional DC conversion circuit 30 can be used to achieve bidirectional DC conversion, including when the battery module 400 is discharged, the discharge voltage of the battery module 400 is converted from DC to DC, and the output voltage of the bidirectional DC conversion circuit 30 is equal to the output voltage of the boost circuit 20, and when the battery module 400 is charged, the bidirectional DC conversion circuit 30 can convert the output voltage of the boost circuit 20 or the output voltage of the rectifier circuit 10 from DC to DC, and output a charging power supply to charge the battery module 400.

[0120] Among them, the photovoltaic module 300 can adopt photovoltaic panels and corresponding energy storage inverters, junction boxes and other structures, the battery module 400 can be composed of multiple single cells connected in series and parallel, the rectifier circuit 10 can include a corresponding rectifier bridge and a switching circuit for controlling the on and off of the rectifier circuit 10, etc., the boost circuit 20 can adopt a boost circuit or a boost converter and other structures, and the bidirectional DC conversion circuit 30 can adopt a bidirectional DC / DC converter or a corresponding DC conversion circuit and other structures.

[0121] Inverter circuit 40 is used to perform inverting conversion between input and output, and outputs AC power to motor 500, which can be a water pump motor, fan motor, compressor motor, etc. Inverter circuit 40 can adopt a corresponding inverter bridge, inverter, or other circuit structure. In an optional embodiment, the inverter module comprises a three-phase fully controlled inverter bridge forming a two-level inverter, which can achieve optimal efficiency control of motor 500.

[0122] The control circuit 50 is connected to the rectifier circuit 10 , the boost circuit 20 , the bidirectional DC conversion circuit 30 and the inverter circuit 40 respectively, and is used to implement the steps of the above power supply control method.

[0123] That is, by detecting the output voltage of the photovoltaic module 300, different working modes are selected and different power sources are started for power supply, and the output voltage of the boost circuit 20 is adjusted according to the first ratio in the first working mode, thereby achieving the maximum power output of the boost circuit 20.

[0124] The excitation flux is adjusted according to the load size, thereby changing the excitation current, and the control mode of the motor 500 is adaptively adjusted according to the load size, so that the motor 500 works at the maximum efficiency point.

[0125] Further, if Figure 1 or Figure 9As shown, the present invention also provides a motor power supply device, which includes a battery module 400, a photovoltaic module 300, and a motor power supply circuit 100. The specific structure of the motor power supply circuit 100 is similar to the above-mentioned embodiments. Since the present motor power supply device adopts all the technical solutions of all the above-mentioned embodiments, it has at least all the beneficial effects brought about by the technical solutions of the above-mentioned embodiments, and will not be described in detail here. The motor power supply circuit 100 is connected to the mains 200, the battery module 400, the photovoltaic module 300, and the motor 500 respectively.

[0126] The motor power supply circuit 100 selects at least one of the mains 200 , the battery module 400 and the photovoltaic module 300 to provide power supply according to the power supply control method, and converts and outputs AC power to the motor 500 , thereby driving the motor 500 to work.

[0127] The embodiments described above are only used to illustrate the technical solutions of the present invention, rather than to limit the same. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. These modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the various embodiments of the present invention, and should all be included in the scope of protection of the present invention.

Claims

1. A power supply control method for controlling a motor power supply circuit, characterized in that: The motor power supply circuit includes a rectifier circuit, a boost circuit, a bidirectional DC conversion circuit and an inverter circuit, the input end of the inverter circuit is respectively connected to the output end of the rectifier circuit, the output end of the boost circuit and the first end of the bidirectional DC conversion circuit, the input end of the rectifier circuit is connected to the mains, the input end of the boost circuit is connected to the photovoltaic module, the second end of the bidirectional DC conversion circuit is connected to the battery module, and the output end of the inverter circuit is connected to the motor; The power supply control method includes: Obtaining the output voltage of the photovoltaic module; When the output voltage is greater than a first preset voltage, switching to a first operating mode, wherein the first operating mode is: shutting down the rectifier circuit and the bidirectional DC conversion circuit, and starting the boost circuit to perform boost conversion and starting the inverter circuit to perform inverter conversion; When the output voltage is less than the first preset voltage, the device switches to a second operating mode, wherein the second operating mode is: shutting down the boost circuit, and starting the rectifier circuit to perform rectification and / or starting the bidirectional DC conversion circuit to perform battery discharge, and starting the inverter circuit to perform inverter conversion; The power supply control method further includes: Detecting the torque current of the motor, obtaining the load of the motor, and comparing the torque current with a torque current setting value to compare the load with a preset load value; When the torque current is less than the torque current setting value, the load is less than the preset load value, PI adjustment is performed on the comparison value between the torque current and the torque current setting value, and the excitation flux is proportionally limited according to the comparison value to reduce the excitation flux of the motor to reduce the excitation current of the motor; When the load is greater than a preset load, the excitation flux of the motor is increased to a rated flux to increase the excitation current of the motor.

2. The power supply control method according to claim 1, wherein: The first working mode also includes: Obtaining the open-circuit voltage of the photovoltaic module and starting the boost circuit to perform boost conversion; The output voltage of the photovoltaic module is obtained, and the duty cycle of the control signal of the boost circuit is adjusted based on the output voltage.

3. The power supply control method according to claim 2, wherein: The obtaining of the output voltage of the photovoltaic module and adjusting the duty cycle of the control signal of the boost circuit based on the output voltage include: When the output voltage of the photovoltaic module is greater than 0.78 times the open circuit voltage, reducing the duty cycle of the switch control signal of the boost circuit; When the output voltage of the photovoltaic module is less than 0.78 times the open circuit voltage, increasing the duty cycle of the switch control signal of the boost circuit; When the output voltage of the photovoltaic module is equal to 0.78 times the open circuit voltage, the duty cycle of the switch control signal of the boost circuit is maintained.

4. The power supply control method according to claim 2, wherein: The first working mode also includes: Obtaining the output power change rate and the output voltage change rate of the photovoltaic module per unit time and performing ratio calculation to obtain a first ratio; The duty cycle and the change rate of the switch control signal of the boost circuit are adjusted according to the first ratio.

5. The power supply control method according to claim 4, wherein: Adjusting the duty cycle and the change rate of the switch control signal of the boost circuit according to the first ratio includes: When the first ratio is greater than zero, increasing the duty cycle of the switch control signal; When the first ratio is less than zero, reducing the duty cycle of the switch control signal; When the first ratio is equal to zero, maintaining the duty cycle of the switch control signal; When the absolute value of the first ratio is greater than a preset value, increasing the rate of change of the duty cycle of the switch control signal; When the absolute value of the first ratio is less than a preset value, the change rate of the duty cycle of the switch control signal is reduced.

6. The power supply control method according to any one of claims 1 to 5, wherein: In the second working mode, starting the rectifier circuit to perform the rectification operation and / or starting the bidirectional DC conversion circuit to perform the battery discharge operation includes: Obtaining the terminal voltage of the battery module; When the terminal voltage of the battery module is greater than a second preset voltage, the boost circuit and the rectifier circuit are turned off, and the bidirectional DC conversion circuit is started to perform battery discharge operation; When the terminal voltage of the battery module is lower than a second preset voltage, the boost circuit and the bidirectional DC conversion circuit are turned off, and the rectifier circuit is started to perform rectification and output operation.

7. The power supply control method according to claim 6, wherein: The first working mode also includes: detecting the terminal voltage of the battery module; When the terminal voltage of the battery module is less than a third preset voltage, turning on the bidirectional DC conversion circuit to charge the battery, and the third preset voltage is less than or equal to the second preset voltage; The second working mode also includes: When the terminal voltage of the battery module is lower than the third preset voltage, the bidirectional DC conversion circuit is turned on to perform battery charging.

8. A motor power supply circuit, characterized in that: The invention comprises a rectifier circuit, a boost circuit, a bidirectional DC conversion circuit, an inverter circuit and a control circuit, wherein the input end of the inverter circuit is respectively connected to the output end of the rectifier circuit, the output end of the boost circuit and the first end of the bidirectional DC conversion circuit, the input end of the rectifier circuit is connected to the mains, the input end of the boost circuit is connected to the photovoltaic module, the second end of the bidirectional DC conversion circuit is connected to the battery module, the output end of the inverter circuit is connected to the motor, and the control circuit is respectively connected to the rectifier circuit, the boost circuit, the bidirectional DC conversion circuit and the inverter circuit; The control circuit is used to implement the steps of the power supply control method according to any one of claims 1 to 7.

9. A motor power supply device, characterized in that: It comprises a battery module, a photovoltaic module and the motor power supply circuit according to claim 8, wherein the motor power supply circuit is connected to the mains, the battery module, the photovoltaic module and the motor respectively.

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