TW201711353A - Rotator angle estimation method capable of increasing the resolution of the Hall sensor and enhancing the precision of the estimated angle - Google Patents

Abstract

Provided is a rotator angle estimation method. A controller is provided to calculate the angular velocity of a rotator and further calculate a changed angle. Then, the changed angle is accumulated by taking the electrical angle of the rotator as a standard, so as to obtain an estimated angle. Furthermore, the estimated angle is adjusted to be a corrected angle by taking the electrical angle of the rotator in generating Hall state-transition signals as a standard. Finally, the corrected angle is used to control the rotation of the rotator through field-oriented control (FOC). Accordingly, not only the resolution of the Hall sensor is increased, but also the precision of the estimated angle is enhanced, whereby the Hall sensor that is intrinsically provided with a low resolution is able to output current with sinusoidal phase to control the rotator for improving the product property of the rotator and reducing the vibration and noise of the rotator during rotation.

Description

Rotor angle estimation method

The invention relates to a control method, in particular to a rotor angle estimation method.

Field-Oriented Control (FOC) is the mainstream technology of today's motor control, and magnetic field steering control needs to be matched with high-resolution rotor angle sensor (Encoder) or sensorless estimation technology (Sensorless). Good sine wave output characteristics.

Although the sensorless estimation technology is low in cost, due to the lack of a sensor, it may be reversed at the beginning of startup, and the starting torque is low, which is not suitable for the control of the vehicle motor drive. Although the rotor angle sensor can improve the shortcomings of the above sensorless estimation technique, the rotor angle sensor of high resolution (about 1024 to 2048 state codes) is costly.

Therefore, recently, related companies have changed to cheaper Hall sensors, which can reduce costs. However, the Hall perceptron only has six kinds of state codes as shown in Fig. 1. That is to say, the resolution of the Hall perceptron is far less than the resolution of the rotor angle perceptron, so that the output current of the magnetic field steering control is as shown in Fig. 2. U-shaped serrated shape, resulting in motor running Vibration and noise.

Accordingly, it is an object of the present invention to provide a rotor angle estimation method for improving the resolution of a Hall sensor to reduce vibration and noise.

The rotor angle estimation method of the present invention comprises the following steps: step (a) detecting a electrical angle of a rotor by using a Hall sensor, and generating a Hall transition signal when the Hall sensor is in a state of transition.

In step (b), the controller receives the Hall transition signal generated by the Hall sensor, and calculates the angular velocity of the rotor from the time difference between the two Hall transition signals.

Step (c) uses the controller to calculate a change angle, which is a product of a preset sampling time of the controller and an angular velocity of the rotor. Step (d) uses the controller to accumulate the angle of change of the electrical angle of the rotor detected by the Hall sensor to generate an estimated angle.

Step (e) using the controller to compare the difference between the electrical angle of the rotor and the predicted angle when the Hall transition signal is generated, and based on the electrical angle of the rotor when the Hall transition signal is generated, The predicted angle is corrected to a correction angle that is the same as the electrical angle of the rotor when the Hall transition signal is generated.

Step (f) controls the rotor with the phase current generated by the corrected angle.

The invention has the beneficial effects that the angular velocity of the rotor is calculated by the controller, and is matched with the low-resolution Hall sensor. The electrical angle of the rotor is used as a reference, and the predicted angle is corrected to a correction angle when the Hall sensor is turned, which not only improves the resolution of the Hall sensor, but also improves the accuracy of the estimated angle to reduce the rotor. Vibration and noise during operation.

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Other features and effects of the present invention will be apparent from the following description of the drawings, wherein: FIG. 1 is a schematic diagram illustrating the six encoding states of a conventional Hall sensor; FIG. 2 is a schematic diagram illustrating The phase current of the output is controlled by the magnetic field of the existing Hall sensor; FIG. 3 is a flow chart illustrating an embodiment of the rotor angle estimation method of the present invention; and FIG. 4 is a schematic diagram illustrating the pre-step of the step (d) of the embodiment. The difference between the angle and the electrical angle of the Hall sensor is estimated; FIG. 5 is a schematic diagram illustrating the difference between the predicted angle and the corrected angle in the present embodiment; and FIG. 6 is a comparison diagram illustrating the resolution of the corrected angle in the present embodiment. The difference in resolution of the Hall perceptron; and Figure 7 is a schematic diagram illustrating the phase current produced by the correction angle of the present embodiment.

Referring to FIG. 3, an embodiment of a rotor angle estimation method of the present invention includes The method includes the following steps: Step 21 uses a Hall sensor to detect the electrical angle of a rotor, and generates a Hall transition signal when the Hall sensor changes state.

In this embodiment, the Hall transition signal is a single phase Hall turn. State signal, in practical applications, the Hall transition signal can also be a three-phase Hall transition signal.

Step 22 is to use a controller to receive the Hall sensor The raw Hall transition signal, and the angular velocity of the rotor is calculated from the time difference between the two Hall transition signals. In this embodiment, the controller is a Microcontroller Unit (MCU), and the actual application may also be a Digital Signal Processor (DSP).

It is important to note here that the controller is a single-phase Hall. The angular signal is used to calculate the angular velocity. Of course, the controller can also calculate the angular velocity by using a three-phase Hall transition signal.

Step 23 is to calculate a change angle by using the controller, The angle of change is the product of a predetermined sampling time of the controller and the angular velocity of the rotor.

Referring to Figures 3 and 4, step 24 is to utilize the controller to the Hall. The electrical angle of the rotor detected by the sensor accumulates the angle of change to produce an estimated angle. As can be seen from FIG. 4, the change in the estimated angle is more fine than the change in the Hall sensor's transition state.

Referring to Figures 3, 4, and 5, step 25 is to compare with the controller. The difference between the electrical angle of the rotor and the predicted angle corresponding to the electrical angle of the rotor when the Hall transition signal is generated, that is, the electrical angle between the electrical angle and the predicted angle in the position of 120° and 180° in FIG. Difference, and to generate the Hall turn In the state signal, the electrical angle of the rotor is used as a reference, and the predicted angle shown by the imaginary coil winding portion in FIG. 4 is corrected to the electrical representation of the rotor as shown in the imaginary coil winding portion in FIG. 5 and when the Hall transition signal is generated. A correction angle of the same angle increases the accuracy of the estimated correction angle. It should be noted that 60°, 120°, 180°, and 240° in FIGS. 4 and 5 are electrical angles when the Hall sensor is in a state of transition.

Since the electrical angle sensed by the Hall sensor is the rotor The electrical angle, therefore, using the Hall sensor to generate the electrical angle of the Hall transition signal to correct the predicted angle, can correct the slight error of the predicted angle and the electrical angle of the rotor, and then obtain the figure Figure 6 shows better resolution and accuracy than the Hall sensor. It should be noted that the correction angle in FIG. 5 is other than the position where the Hall sensor generates the electrical angle of the Hall transition signal (ie, the 120° and 180° positions in FIGS. 4 and 5). The rest is the same as the estimated angle in Figure 4.

Referring to Figures 3, 6, and 7, step 26 is produced at the corrected angle. The raw sine wave phase current controls the rotor to rotate. Since the resolution of the correction angle is better than that of the Hall sensor, the phase current of the sine wave as shown in FIG. 7 can be generated by the correction angle. Compared with the existing Hall sensor, the U-shaped sawtooth phase current, the phase current of the sine wave can not only make the rotation of the rotor smoother, but also reduce the vibration and noise during rotation.

In summary, the rotor angle estimation method of the present invention utilizes the control The controller calculates the angular velocity and the change angle of the rotor, and corrects the predicted angle to the correction angle based on the electrical angle when the Hall sensor is in the transition state. In order to improve the resolution and accuracy of the Hall sensor to reduce vibration and noise during rotor operation, the object of the present invention can be achieved.

However, the above is only the preferred embodiment of the present invention. The scope of the present invention is not limited thereto, that is, the simple equivalent changes and modifications made by the present invention in the scope of the invention and the scope of the patent specification are still within the scope of the invention.

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Claims (5)

A rotor angle estimation method includes the following steps: (a) detecting a electrical angle of a rotor by using a Hall sensor, and generating a Hall transition signal when the Hall sensor is in a state of transition; (b) Receiving, by a controller, the Hall transition signal generated by the Hall sensor, and calculating an angular velocity of the rotor from a time difference between the two Hall transition signals; (c) calculating a change angle by using the controller The change angle is a product of a preset sampling time of the controller and an angular velocity of the rotor; (d) using the controller to accumulate the change angle by the electrical angle of the rotor detected by the Hall sensor to generate a pre- (e) using the controller to compare the difference between the electrical angle of the rotor and the estimated angle when the Hall transition signal is generated, and based on the electrical angle of the rotor when the Hall transition signal is generated. And correcting the predicted angle to a correction angle that is the same as the electrical angle of the rotor when the Hall transition signal is generated; and (f) controlling the rotor with the phase current generated by the corrected angle. The rotor angle estimation method according to claim 1, wherein the Hall transition signal in the step (a) is a single-phase Hall transition signal. The rotor angle estimation method according to claim 1, wherein the Hall transition signal in the step (a) is a multi-phase Hall transition signal. The rotor angle estimation method according to claim 1, wherein the controller in the step (b) is one selected from the group consisting of a microprocessor or a digital signal processor. The rotor angle estimation method according to claim 1, wherein the phase current in the step (f) is a sine wave type.