A non-inductive FOC tailwind starting method

Abstract

The application discloses a kind of inductive FOC wind start method, it is related to motor field, the inductive FOC wind start method includes the following steps: step 1, motor is in wind state or adverse wind state, open three-phase lower bridge arm, open time is T sh ;Step 2, obtain three-phase motor current I u , I v , I w , I α , I β , again arctangent operation obtains phase angle θ1;Step 3, close three-phase lower bridge arm, close time continues T 12 ;ω eMax It is the highest speed of motor;Compared with prior art, the beneficial effects of the application are: the application does not need position sensor and quickly and reliably estimates the initial position of motor rotor, can identify the initial position of motor in a very short time, and motor does not occur any rotation in identification process;Compared with the product of position sensor motor and driver, the cost of motor position sensor is saved.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of electric machines, in particular to a non-inductive FOC wind start method. BACKGROUND

[0002] Traditional permanent magnet synchronous motors are mostly equipped with position sensors so that the controller can obtain the motor rotor position using the sensor, and then normally drive the motor, but the introduction of the position sensor not only increases the cost of hardware, but also increases the difficulty of production and installation, and the requirements for the process also increase, and because the position sensor usually needs an additional wire harness connected to the controller, so in the process of use, the motor drive system often cannot be used normally due to factors such as wire harness aging and poor contact.

[0003] Therefore, products of position sensorless motors and drivers appear, and in many products equipped with position sensorless motors and drivers, when the controller is powered off, the motor will still rotate freely at a certain speed due to inertia factors, and when the controller is powered on again during this period, the motor needs to be restarted after it completely stops, which may be relatively long, thereby reducing the system utilization.

[0004] The solution is that the load object of the position sensorless motor is fluid, such as a fan, a pump or a large rotational inertia motor, which can realize fast restart without waiting for the motor to stop during rotation, but it is limited to the load object of the position sensorless motor and needs to be improved. SUMMARY

[0005] The purpose of the present application is to provide a non-inductive FOC wind start method to solve the problems raised in the background art.

[0006] To achieve the above purpose, the present application provides the following technical scheme:

[0007] A non-inductive FOC wind start method, comprising the following steps:

[0008] Step 1: The motor is in a wind state or an adverse wind state, and the three-phase lower bridge arms are turned on, and the turn-on time is T sh ;

[0009] Step 2: Obtain three-phase motor currents I u , I v , I w , get I α , I β by coordinate transformation, and then get the phase included angle θ1 by arctangent operation;

[0010] Step 3: Close the three-phase lower bridge arms, and the closing time lasts for T 12 ; Where ω eMaxThe highest speed of the motor is obtained;

[0011] Step 4, repeating steps 1 and 2 to obtain the phase angle θ2; and turning off the three-phase lower bridge arm;

[0012] Step 5, calculating the current motor electrical angle through the phase angles θ1 and θ2;

[0013] Step 6, judging whether the motor is in the downwind state or the upwind state based on the motor speed and the motor rotation direction;

[0014] Step 7, when the calculated motor speed is higher than the set threshold, the calculated angle and speed are brought into the observer for direct closed-loop cutting-in.

[0015] As a further scheme of the application: in step 1, the motor is in the downwind state or the upwind state, the lower bridge arm short-circuit pulse mode is adopted, the three-phase lower bridge arm is turned on, and the on time is T sh .

[0016] As a further scheme of the application: under the premise of ensuring reliable sampling and required signal-to-noise ratio, the on time T sh is ensured to be short enough.

[0017] As a further scheme of the application: in step 2, i1(T sh ) is the first short pulse current, θ I1 is the angle between the current vector and the U phase, θ0 is the angle between the current vector and the d axis, θ1 is the angle between the d axis and the U phase, and the motor back electromotive force electrical angle is obtained:

[0018] θ1=θ I1 +θ0 (1).

[0019] As a further scheme of the application: in step 5, the current motor speed is calculated:

[0020]

[0021] The current motor electrical angle is calculated:

[0022]

[0023] As a further scheme of the application: in step 6, when the motor speed ω e is consistent with the motor rotation direction, the motor is in the downwind state, and when the motor speed ω e is opposite to the motor rotation direction, the motor is in the upwind state.

[0024] As a further scheme of the application: in step 7, when the calculated motor speed is higher than the set threshold, i.e., |ω e |>ω ThrThe calculated angle and rotating speed are directly closed into the observer to cut in.

[0025] Compared with the prior art, the motor rotor initial position is estimated quickly and reliably without a position sensor, the motor initial position is identified in a very short time, and the motor does not rotate during the identification process; compared with a product with a position sensor motor and a driver, the cost of the motor position sensor is saved. BRIEF DESCRIPTION OF DRAWINGS

[0026] Figure 1 A schematic diagram of the motor rotation electric angle. DETAILED DESCRIPTION

[0027] The technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, rather than all the embodiments of the present application. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor fall within the scope of protection of the present application.

[0028] Please refer to Figure 1 A non-inductive FOC (field-oriented control) wind start method, comprising the following steps:

[0029] Step 1, the motor is in a wind state or an adverse wind state, the three-phase lower bridge arm is turned on, and the turn-on time is T sh ;

[0030] Step 2, the three-phase motor currents I u , I v , I w are obtained, I α , I β are obtained through coordinate transformation, and the phase included angle θ1 is obtained through arctangent operation; the specific calculation formula is as follows:

[0031] I α = I u

[0032]

[0033] Step 3, the three-phase lower bridge arm is turned off, and the turn-off time lasts for T 12 ; Wherein ω Max is the highest rotating speed of the motor;

[0034] Step 4, the phase included angle θ2 is obtained by repeating steps 1 and 2, and the three-phase lower bridge arm is turned off;

[0035] Step 5, the current motor electric angle is calculated through the phase included angles θ1 and θ2.

[0036] Step 6, determine whether the motor is in the downwind state or the upwind state based on the motor speed and the motor rotation direction;

[0037] Step 7, when the calculated motor speed is higher than the set threshold, the calculated angle and speed are brought into the observer for direct closed-loop cutting-in.

[0038] In a specific embodiment: the motor is in the downwind state or the upwind state, and the three-phase lower bridge arms are turned on at the same time, and the turn-on time is T sh The motor stator dq voltage equation is as follows:

[0039]

[0040] When T sh is small enough to satisfy , R s can be approximated to 0, and opening the three-phase lower bridge arms is equivalent to U d = 0, U q = 0, and the above formula can be transformed as:

[0041]

[0042] After the Laplace transformation, we get:

[0043]

[0044] Since the short-circuit time T sh is short enough, so For surface-mounted motors, L q and L d can be approximated to be equal, so Since the back electromotive force leads the flux linkage phase , the current motor electrical angle is:

[0045]

[0046] In this embodiment: in step 1, the motor is in the downwind state or the upwind state, and the three-phase lower bridge arms are turned on in the short-circuit pulse mode, and the turn-on time is T sh .

[0047] In this embodiment: first, the sampling must be reliable, that is, the turn-on time must be greater than the current sampling time, which is related to the driving chip; second, the required signal-to-noise ratio must be ensured, that is, the current signal at the end of the lower tube turn-on stage must reach a relatively stable state, which is usually affected by motor parameters; under the above two conditions, the turn-on time T sh should be short enough, generally, T sh is taken in the interval of 1 / 100 to 1 / 10 of the control period.

[0048] In the embodiment, refer to Figure 1 , in step 2, i1(T sh ) is the first short pulse current, θ I1 is the angle between the current vector and U phase, θ0 is the angle between the current vector and d axis, θ1 is the angle between d axis and U phase, and the motor back electromotive force electrical angle is obtained:

[0049] θ1=θ I1 +θ0 (1)。

[0050] θ2 is calculated in the same way as θ1, and the difference lies in that the motor rotates for a certain time to change the electrical angle.

[0051] In the embodiment, in step 5, the current motor speed is calculated:

[0052]

[0053] The current motor electrical angle is calculated:

[0054]

[0055] In the embodiment, in step 6, when the motor speed ω e is consistent with the motor rotating direction, the motor is in the downwind state, and when the motor speed ω e is opposite to the motor rotating direction, the motor is in the upwind state.

[0056] In the embodiment, in step 7, when the calculated motor speed is higher than the set threshold, i.e., |ω e |>ω Thr , the calculated angle and speed are brought into the observer to directly close loop and cut in.

[0057] The application estimates the motor rotor initial position quickly and reliably without position sensor, can identify the motor initial position in a very short time, and the motor does not rotate during the identification process; compared with the product with position sensor motor and driver, the cost of the motor position sensor is saved.

[0058] It is obvious for those skilled in the art that the application is not limited to the details of the above exemplary embodiments, and the application can be implemented in other specific forms without departing from the spirit or essential characteristics of the application. Therefore, the embodiments should be regarded as exemplary and non-limiting from any point of view.

[0059] Furthermore, it should be understood that although the specification is described in terms of embodiments, not every embodiment includes every feature described. The specification can include implicit combinations of explicitly mentioned features and / or explicit combinations of implicitely mentioned features. Each embodiment depends on the explicit combinations of features and / or the implicit combinations of features made specifically within that embodiment, and each such embodiment can be combined with every other such embodiment to create further embodiments.

Claims

1. A method for starting up a wind in the direction of the wind without induction FOC, characterized in that, The non-inductive FOC tailwind starting method comprises the following steps: Step 1, the motor is in the downwind state or the upwind state, the three-phase lower bridge arm is turned on, and the turn-on time is ; Step 2, get three-phase motor current , get the phase angle through coordinate transformation , and get the phase angle through arctangent operation ; Step 3, turn off the lower bridge arm of the three-phase, the turn-off time lasts for ; wherein is the maximum speed of the motor; Step 4, repeat steps 1, 2 to get the angle between the phases ; and turn off the lower bridge arm of the three-phase Step 5, the current motor electrical angle is calculated by the phase angle between the voltage and the current Step 6, judge whether the motor is in tailwind state or headwind state based on the motor speed and the motor rotation direction; Step 7, when the calculated motor speed is higher than the set threshold, the calculated angle and speed are brought into the observer for direct closed-loop cut-in; In step 5, the current motor speed is calculated: （2）； The current motor electrical angle is calculated: ； （3）。 2. The inductive FOC downwind start method of claim 1, wherein, In step 1, the motor is in the downwind state or the upwind state, the lower bridge arm short circuit pulse mode is taken, the three-phase lower bridge arm is turned on, and the turn-on time is .

3. The inductive FOC downwind start method according to claim 1 or 2, characterized in that, To ensure the opening time under the premise of ensuring the reliability of sampling and the demand signal-to-noise ratio Short enough.

4. The non-inductive FOC wind start method of claim 1, wherein, In step 2, for the first short pulse current, for the angle between the current vector and the u-phase, for the angle between the current vector and the d-axis, for the angle between the d-axis and the u-phase, the motor back EMF electrical angle is obtained: （1）。 5. The non-inductive FOC wind start method of claim 1, wherein, In step 6, when the motor rotation speed is the same as the wind direction, the motor is in the downwind state, and when the motor rotation speed is opposite to the wind direction, the motor is in the upwind state.

6. The inductive FOC downwind start method of claim 1, wherein, In step 7, when the calculated motor speed is higher than the set threshold, i.e. The calculated angle and speed are then fed into the observer to directly close the loop.

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