Blower fan upwind starting detection system

Abstract

The utility model discloses a detection system for upwind starting of a fan, which relates to the technical field of fan control and adopts the technical scheme that a main control module can receive current feedback of a motor and control the motor; the amplification module is arranged between the motor and the main control module and can sample and amplify the current of the motor and then output the current to the main control module; the speed signal module is electrically connected with the main control module and can input a target rotating speed in a voltage form to the main control module; and the IPM control module is electrically connected with the main control module and the motor to form a control loop between the main control module and the motor. The beneficial effects of the utility model are that when the motor is started, the main control module obtains the current of the motor through the amplification module, and determines whether the starting scheme is headwind starting or normal starting according to the magnitude of the current obtained through sampling. According to the scheme, a back electromotive force detection circuit does not need to be added, the cost can be reduced, and meanwhile, the situation of dead wind misjudgment caused by back electromotive force detection deviation or abnormity is avoided.

Description

Technical Field

[0001] The utility model relates to the technical field of fan control, in particular to a fan headwind start-up detection system. Background Art

[0002] If a fan is installed outdoors (such as an air conditioner's outdoor fan), and strong winds are experienced while the motor is stationary, the wind can cause the fan to rotate in the opposite direction, effectively creating a counter-wind condition. If a motor start command is received at this point and the fan is started according to normal procedures, this can easily cause the motor to fail to start, potentially damaging circuit components and the motor. Therefore, to improve the reliability of fan startup outdoors, the fan must be equipped with counter-wind detection and startup capabilities.

[0003] The normal motor start process is as follows: upon receiving the motor start command, the motor controller sends a positioning current to the motor, positioning the motor rotor in a fixed position. The motor controller then continues to send current to the motor, operating in open-loop control. After forcing the motor to a certain speed, closed-loop speed control begins. If the motor is started normally in a headwind situation, the starting torque applied to the motor will be less than the headwind torque, causing the motor to lose step and fail to start.

[0004] Current solutions primarily calculate fan speed by detecting the motor's back EMF, determining it as headwind speed when the headwind speed is less than 0. This back EMF headwind detection solution requires hardware to add back EMF detection circuitry, increasing hardware cost. Furthermore, detection may fail if the fan is in a headwind state at low speed. Furthermore, if the relevant detection hardware fails, headwind detection becomes impossible. Utility Model Content

[0005] In view of one of the deficiencies of the prior art, the utility model provides a fan headwind start-up detection system to solve the problem of headwind detection and start-up of outdoor fans.

[0006] To achieve the above-mentioned purpose, the present invention provides the following technical solutions: a fan headwind start-up detection system, comprising:

[0007] The main control module, as the main control unit, can receive the current feedback of the motor and control the motor;

[0008] The amplification module is arranged between the motor and the main control module, and can sample the current of the motor and amplify it before outputting it to the main control module;

[0009] a speed signal module, electrically connected to the main control module, and capable of inputting a target speed in the form of a voltage into the main control module;

[0010] The IPM control module is electrically connected to the main control module and the motor respectively, forming a control loop between the main control module and the motor.

[0011] Preferably, the motor is a three-phase motor, and the main control module can sample two or three phases of the motor through the amplification module.

[0012] Preferably, the amplification module includes:

[0013] Amplifier, which is an operational amplifier chip;

[0014] Amplifying input terminals, each corresponding to two or three phases of the motor and electrically connected to the amplifier;

[0015] An amplifying output terminal is provided for each of the two or three phases of the motor, and the amplifying output terminal is electrically connected to the main control module to form a feedback loop.

[0016] Preferably, the amplifier in the amplification module is an operational amplifier.

[0017] Preferably, the amplification module further includes:

[0018] The feedback circuit is arranged between the output terminal and the input terminal of the amplifier.

[0019] Preferably, the speed signal module is a speed signal input circuit, and two voltage-dividing resistors connected in series are provided in the signal input circuit; the speed signal input circuit is also provided with a filter circuit.

[0020] Preferably, the main control module is an MCU chip, and the main control module is provided with an input terminal corresponding to the amplification output terminal of the amplification module, which can amplify the sampling of the motor V-phase and W-phase currents by the amplification module;

[0021] The main control module is provided with an input terminal corresponding to the speed signal module, and the input terminal can receive a target speed input signal in the form of a voltage;

[0022] The main control module is provided with HIN and LIN input terminals corresponding to the three phases of the motor respectively, and the HIN and LIN input terminals can output control signals to the IPM control module.

[0023] Preferably, the IPM control module is provided with three drive circuits and six switch tube modules corresponding to the HIN and LIN input terminals of the main control module;

[0024] The three driving circuits are respectively arranged corresponding to the U phase, V phase and W phase of the motor.

[0025] Preferably, the three driving circuits are respectively provided with voltage output terminals corresponding to the U phase, the V phase and the W phase.

[0026] Preferably, the negative end of the output end of the two-phase or three-phase drive circuit of the motor is respectively provided with a sampling resistor.

[0027] Compared with the existing technology, it has the following beneficial effects:

[0028] With this solution, when the motor starts, the main control module first obtains the motor current through the amplification module, and determines whether the starting scheme is headwind start or normal start based on the current size obtained by sampling.

[0029] This solution does not require the addition of a back electromotive force detection circuit, which can reduce costs and avoid the misjudgment of headwind due to back electromotive force detection deviation or abnormality. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Figure 1 This is a principle block diagram of an embodiment of the present application;

[0031] Figure 2 This is a schematic diagram of the main control module of an embodiment of the present application;

[0032] Figure 3 This is a schematic diagram of an amplification module according to an embodiment of the present application;

[0033] Figure 4 This is a schematic diagram of a speed signal module according to an embodiment of the present application;

[0034] Figure 5 This is a schematic diagram of the IPM control module of an embodiment of the present application. DETAILED DESCRIPTION

[0035] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the embodiments described are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0036] See also Figure 1-Figure 5 , this application provides the following technical solutions:

[0037] A wind turbine headwind startup detection system includes a main control module as the main control unit, which receives motor current feedback and controls the motor. An amplifier module is provided between the motor and the main control module, which samples the motor current, amplifies it, and outputs it to the main control module. A speed signal module is electrically connected to the main control module, which inputs a target speed in the form of a voltage to the main control module. An IPM control module is also provided, which is electrically connected to the main control module and the motor, forming a control loop between the main control module and the motor.

[0038] With this solution, when the motor starts, the main control module first obtains the motor current through the amplifier module. Based on the sampled current, it determines whether the start-up is headwind or normal. This solution eliminates the need for additional back-EMF detection circuitry, reducing costs and preventing misjudgment of headwind due to deviations or anomalies in back-EMF detection.

[0039] On the basis of the above implementation scheme, the motor applicable to this solution is a three-phase motor, and the main control module can sample the two-phase or three-phase current of the motor through the amplification module.

[0040] The amplification module includes an operational amplifier. The amplification module is provided with two or three amplification input terminals electrically connected to the amplifier corresponding to two or three phases of the motor, and an amplification output terminal is provided for each of the two or three phases of the motor. The amplification output terminals are electrically connected to the main control module to form a feedback loop. A feedback circuit is provided between the output terminal and the input terminal of the amplifier.

[0041] The speed signal module is a speed signal input circuit, in which two voltage-dividing resistors connected in series are arranged; and a filter circuit is also arranged in the speed signal input circuit.

[0042] The main control module is an MCU chip, and the main control module is provided with an input terminal corresponding to the amplification output terminal of the amplification module, which can amplify the sampling of the two-phase or three-phase current of the motor by the amplification module; the main control module is provided with an input terminal corresponding to the speed signal module, and the input terminal can receive the target speed input signal in the form of voltage; the main control module is provided with HIN and LIN input terminals corresponding to the V phase, W phase and U phase of the motor respectively, and the HIN and LIN input terminals can output control signals to the IPM control module.

[0043] The IPM control module is equipped with three drive circuits and six switching tube modules corresponding to the HIN and LIN input terminals of the main control module. The three drive circuits are respectively provided for the U, V, and W phases of the motor. The three drive circuits are respectively provided with voltage output terminals corresponding to the U, V, and W phases of the motor. The negative terminals of the output terminals of the drive circuits corresponding to the U, V, and W phases are respectively provided with sampling resistors.

[0044] Different headwind levels are preset based on the magnitude of the two-phase or three-phase sampled current of the motor, and different starting parameters are preset for each headwind level, including the motor's braking time, positioning current, and rotor pre-positioning starting position. When the start signal is received, the corresponding headwind speed level is determined based on the results obtained from the motor current sampling. The main control module then generates the corresponding outputs for the braking time, positioning current, and rotor pre-positioning starting position. When the predetermined braking time and rotor pre-position are reached, the motor is controlled to start normally.

[0045] This solution does not require a back EMF detection circuit, reducing driver board costs and avoiding headwind startup failures caused by hardware failure. Furthermore, this solution can set different startup conditions based on different headwind levels, effectively improving the success rate of headwind startups.

[0046] Based on the above implementation plan, see Figure 2 , Figure 2 This is the schematic diagram of the MCU main control module used in this solution. The Iu_out, Iv_out, and Iw_out pins respectively perform AD sampling on two or three phases of the motor. The MCU main control module calculates the three-phase current of the motor from these samplings. The sampling source for Iu_out, Iv_out, and Iw_out is the amplifier module. Through Field-Oriented Control (FOC) control, the U, V, and W three-phase voltages are calculated based on the target and actual speeds, target and actual currents, and the rotor position angle. This is then used to generate a three-phase PWM output, controlling the three-phase inverter and driving the wind turbine motor. Figure 2 The corresponding pins for WHIN, VHIN, UHIN, ULIN, VLIN, and WLIN in the IPM circuit module output the target speed input. The corresponding pin for Speed_Vsp_In is the target speed input, which is a voltage input from the speed signal module. After A / D conversion by the MCU main control module, the target speed can be calculated.

[0047] Based on the above implementation plan, see Figure 3This is an operational amplifier circuit diagram. Using the directions in the diagram as a reference, the operational amplifier inputs are Iu+ / Iu-, Iv+ / Iv-, and Iw+ / Iw-, representing the voltages of the motor's three-phase currents flowing through the sampling resistors. This module amplifies the voltages and outputs them to the MCU for A / D conversion, calculating the U, V, and W phase currents. Its outputs are Iu_out, Iv_out, and Iw_out. As shown in the figure, a resistor is provided in the circuits connecting Iu+ / Iu-, Iv+ / Iv-, and Iw+ / Iw-, respectively. These resistors are R68, R69, R72, R73, R63, and R64. The feedback circuit uses a series resistor circuit.

[0048] Based on the above implementation plan, see Figure 4 The figure shows the speed signal input circuit. The speed signal is in voltage form, proportional to the speed value. Speed_Vsp is the voltage value. After being divided by resistors R30 and R32, it is sent to the MCU main control module Speed_Vsp_In to calculate the target speed value. In addition, a switching diode, resistor R32, and capacitor C2 are connected in parallel between resistors R30 and R31.

[0049] Based on the above implementation plan, see Figure 5 Figure 1 shows the IPM control module circuit. The IPM control module receives PWM signals from the MCU main control module, namely the WHIN, VHIN, UHIN, ULIN, VLIN, and WLIN output signals from the aforementioned MCU main control module. The IPM control module has three built-in drive circuits and six switching transistors. The three drive circuits correspond to the motor's U, V, and W phases, respectively. Figure 5 Pin 2 of the IPM chip is the U phase voltage output, pin 4 is the V phase voltage output, and pin 6 is the W phase voltage output, which are connected to the U, V, and W phases of the motor respectively. Pin 3 is the negative terminal of the U phase, from which the U phase current flows through the sampling resistor to GND. Pin 5 is the negative terminal of the V phase, from which the V phase current flows through the sampling resistor to GND. Pin 7 is the negative terminal of the W phase, from which the W phase current flows through the sampling resistor to GND. Figure 5 As shown, pin 3 outputs Iu+, pin 5 outputs Iv+, and pin 7 outputs Iw+. Iu+, Iv+, and Iw+ are connected in parallel and then connected to the CSC pin of the IPM chip. Resistors R40, R11, and R13 are connected in series in the Iu+, Iv+, and Iw+ circuits, respectively.

[0050] In the description of the present application and its embodiments, it should be understood that the terms "top", "bottom", "height", etc. indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings. They are only for the convenience of describing the present 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. Therefore, they should not be understood as limitations on the present application.

[0051] In this application and its embodiments, unless otherwise expressly specified or limited, terms such as "disposed," "installed," "connected," "connected," and "fixed" should be understood in a broad sense. For example, they may refer to fixed connections, detachable connections, or integration; mechanical connections, electrical connections, or communication; direct connections or indirect connections through an intermediate medium; and internal connections between two components or interactions between two components. Those skilled in the art will understand the specific meanings of the above terms in this application based on specific circumstances.

[0052] In the present application and its embodiments, unless otherwise expressly specified and limited, a first feature being "above" or "below" a second feature may include the first and second features being in direct contact, or may include the first and second features being in contact not directly but through another feature between them. Moreover, a first feature being "above," "above," and "above" a second feature includes the first feature being directly above and obliquely above the second feature, or simply indicates that the first feature is higher in level than the second feature. A first feature being "below," "below," and "below" a second feature includes the first feature being directly above and obliquely above the second feature, or simply indicates that the first feature is lower in level than the second feature.

[0053] The disclosure above provides many different embodiments or examples for realizing the different structures of the present application. In order to simplify the disclosure of the present application, the components and settings of specific examples are described above. Of course, they are merely examples and are not intended to limit the present application. In addition, the present application may repeat reference numerals and / or reference letters in different examples, and such repetition is for the purpose of simplicity and clarity, and does not itself indicate the relationship between the various embodiments and / or settings discussed. In addition, the present application provides examples of various specific processes and materials, but those of ordinary skill in the art will appreciate the application of other processes and / or the use of other materials.

[0054] Although the preferred embodiments of the present application have been described, those skilled in the art may make additional changes and modifications to these embodiments once they have learned the basic creative concept. Therefore, the appended claims are intended to be interpreted as including the preferred embodiments and all changes and modifications that fall within the scope of the present application.

[0055] Obviously, those skilled in the art may make various changes and modifications to this application without departing from the spirit and scope of this application. Thus, if these modifications and variations of this application fall within the scope of the claims of this application and their equivalents, this application is intended to include these modifications and variations.

Claims

1. A fan headwind start detection system, characterized in that: include: The main control module can receive the current feedback of the motor and control the motor; The amplification module is arranged between the motor and the main control module, and can sample the current of the motor and amplify it before outputting it to the main control module; a speed signal module, electrically connected to the main control module, and capable of inputting a target speed in the form of a voltage into the main control module; The IPM control module is electrically connected to the main control module and the motor respectively, forming a control loop between the main control module and the motor.

2. The wind turbine headwind startup detection system according to claim 1, characterized in that: The motor is a three-phase motor, and the main control module can sample two or three phases of the motor through the amplification module.

3. The wind turbine headwind startup detection system according to claim 2, characterized in that: The amplification module includes: Amplifier, which is an operational amplifier chip; Amplifying input terminals, each corresponding to two or three phases of the motor and electrically connected to the amplifier; An amplifying output terminal is provided for each of the two or three phases of the motor, and the amplifying output terminal is electrically connected to the main control module to form a feedback loop.

4. The wind turbine headwind startup detection system according to claim 3, characterized in that: The amplifier in the amplification module is an operational amplifier.

5. The wind turbine headwind startup detection system according to claim 4, characterized in that: The amplification module further includes: The feedback circuit is arranged between the output terminal and the input terminal of the amplifier.

6. The wind turbine headwind startup detection system according to claim 5, characterized in that: The speed signal module is a speed signal input circuit, in which two voltage-dividing resistors connected in series are arranged; and a filter circuit is also arranged in the speed signal input circuit.

7. The wind turbine headwind startup detection system according to claim 6, characterized in that: The main control module is an MCU chip, and the main control module is provided with an input terminal corresponding to the amplification output terminal of the amplification module, which can amplify the sampling of the two-phase or three-phase current of the motor by the amplification module; The main control module is provided with an input terminal corresponding to the speed signal module, and the input terminal can receive a target speed input signal in the form of a voltage; The main control module is provided with HIN and LIN input terminals corresponding to the three phases of the motor respectively, and the HIN and LIN input terminals can output control signals to the IPM control module.

8. The wind turbine headwind startup detection system according to claim 7, characterized in that: The IPM control module is provided with 3 driving circuits and 6 switch tube modules corresponding to the HIN and LIN input terminals of the main control module; The three driving circuits respectively correspond to the three-phase settings of the motor.

9. The wind turbine headwind startup detection system according to claim 8, characterized in that: The three driving circuits are respectively provided with voltage output terminals corresponding to the three phases of the motor.

10. The wind turbine headwind startup detection system according to claim 9, characterized in that: The negative end of the output end of the two-phase or three-phase drive circuit of the motor is respectively provided with a sampling resistor.

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