CN211296602U - Position detection circuit of switched reluctance motor of food processor - Google Patents

Abstract

The utility model discloses a food preparation machine switched reluctance motor's position detection circuit, switched reluctance motor include stator module, rotor subassembly and position detection circuit, and this position detection circuit includes: the position detection device is used for detecting the position of the rotor of the reluctance motor, and the signal adjusting circuit is used for adjusting the output signal of the position detection device; the position detection device is arranged on the rotor assembly, and the signal adjusting circuit is communicated with the position detection device. The utility model discloses a food preparation machine switched reluctance motor's position detection circuit can ensure that the position detection is accurate, and reduces the position detection cost.

Description

Position detection circuit of switched reluctance motor of food processor

Technical Field

The utility model relates to a kitchen appliances field, more specifically relates to a food preparation machine switched reluctance motor's position detection circuit.

Background

A Switched Reluctance Motor (SRM) is a type of speed-adjustable Motor developed after a dc Motor and a brushless dc Motor. Because the switched reluctance motor has simple and firm structure, wide speed regulation range and high system reliability, the switched reluctance motor is more and more applied to food processing machines at present.

The existing motor position detection methods are mostly Hall or single-grating detection methods, and the Hall detection methods have the problem of no steep rising edge under the condition of high rotating speed, so that the rising edge is detected to be abnormal or delayed, and the control is abnormal. The single grating detection mode cannot effectively filter interference, and control is out of sequence or abnormal opening can be caused when the interference state is introduced. Meanwhile, in the process of switching on the motor, the Hall effect can be also influenced due to the vector performance of the electromagnetism generated by the switched reluctance motor.

In order to avoid the above defects of the hall or single grating detection mode, the existing reluctance motor mostly adopts a code disc mode to perform position detection, but adopts a code disc mode to perform detection, and the cost is high.

SUMMERY OF THE UTILITY MODEL

The embodiment of the utility model provides a food preparation machine switched reluctance motor's position detection circuit, switched reluctance motor includes stator module, rotor subassembly and position detection circuit, position detection circuit includes: the position detection device is used for detecting the position of the rotor of the reluctance motor, and the signal adjusting circuit is used for adjusting the output signal of the position detection device;

the position detection device is arranged on the rotor assembly, and the signal adjusting circuit is communicated with the position detection device.

Optionally, the signal adjusting circuit is a level-triggered circuit, and when an output signal of the position detecting circuit reaches a preset threshold, an output of the signal adjusting circuit changes.

Optionally, the signal adjusting circuit is a nand gate array including M nand gates, where M is an integer greater than 1; the input end of each NAND gate is communicated with the output end of the position detection device.

Optionally, the signal adjusting circuit is a nand schmitt trigger.

Optionally, the position detection device includes N pairs of grating assemblies, where N is an integer greater than 1;

each pair of grating assemblies comprises two gratings, and the output end of each grating is communicated with the input end of one NAND gate.

Optionally, the value of M matches the number of gratings.

Optionally, a first preset angle is formed between two gratings in each pair of grating assemblies.

Optionally, a second preset angle is formed between two rotor salient poles in the rotor assembly, and the second preset angle is different from the first preset angle.

Optionally, the first predetermined angle is 75 ° and the second predetermined angle is 60 °.

Optionally, a light chopper is arranged on each rotor salient pole, when the grating is not shielded by the light chopper, the grating outputs a high level, and the signal adjusting circuit outputs a high level; when the grating is shielded by the light chopper, the grating outputs a low level, and the signal adjusting circuit outputs a low level.

The utility model discloses an at least embodiment provides a food preparation machine switched reluctance motor's position detection circuit compares with prior art, has following beneficial effect: the mode of the position detection device and the signal adjusting circuit is adopted for detecting the position of the rotor of the reluctance motor and adjusting the output signal of the position detection device, so that the position detection accuracy can be ensured, and the cost advantage is obvious compared with the existing code disc mode.

The utility model discloses an in some embodiments, can also reach following effect:

1. the signal adjusting circuit adopts a level triggering circuit, and firstly, the signal adjusting circuit has a level triggering characteristic and can effectively filter interference; and secondly, the sensor has positive and negative threshold characteristics, and can improve the steep change state of the level, thereby ensuring accurate position detection.

2. The signal adjusting circuit can be a NAND gate array, namely a multi-stage NAND gate filter circuit is provided, and common-mode interference of signals is effectively removed.

3. The position detection device for detecting the position of the rotor by the grating can improve the identifiability of the rising edge; and the grating is adopted to replace a Hall element scheme, so that the interference of the rotating electromagnetism of the motor to the detection element can be reduced.

4. The position detection circuit adopts a grating and NAND gate array scheme, so that the position detection cost can be reduced, and the cost is lower compared with the code disc position detection. And secondly, the edge detectability can be improved, and compared with the Hall, the grating mutation and the mutation of the logic NAND gate Schmitt trigger are more obvious and are not influenced by the rotating speed.

5. The angle between the two gratings is different from the angle between the two rotor salient poles, so that the gratings can be conducted when the rotor salient poles rotate for one circle, and the position of the rotor can be detected.

Additional features and advantages of the invention will be set forth in the description which follows, and in part will be obvious from the description, or may be learned by the practice of the invention. The objectives and other advantages of the invention may be realized and attained by the structure particularly pointed out in the written description and drawings.

Drawings

The accompanying drawings are included to provide a further understanding of the embodiments of the present invention and are incorporated in and constitute a part of this specification, illustrate embodiments of the invention and together with the description serve to explain the embodiments of the invention and not to limit the embodiments of the invention.

Fig. 1 is a schematic structural diagram of a position detection circuit of a switched reluctance motor of a food processor according to an embodiment of the present invention;

fig. 2 is a schematic structural diagram of grating detection provided in an embodiment of the present invention;

fig. 3 is a schematic structural diagram of a non-gate array in a grating and signal conditioning circuit according to an embodiment of the present invention;

fig. 4 is a motor state transition diagram provided in the embodiment of the present invention;

fig. 5 is a signal variation diagram corresponding to fig. 4.

Detailed Description

In order to make the objects, technical solutions and advantages of the present invention more apparent, embodiments of the present invention will be described in detail below with reference to the accompanying drawings. It should be noted that the embodiments and features of the embodiments in the present application may be arbitrarily combined with each other without conflict.

The embodiment of the utility model provides a food preparation machine switched reluctance motor's position detection circuit, this switched reluctance motor can include stator module, rotor subassembly and position detection circuit. Specifically, fig. 1 is the embodiment of the utility model provides a food preparation machine switched reluctance motor's position detection circuit's schematic structure, as shown in fig. 1, the embodiment of the utility model provides a position detection circuit can include: position detection means 11 for detecting the position of the rotor of the reluctance motor, and a signal adjusting circuit 12 for adjusting the output signal of the position detection means; position detection means 11 are provided on the rotor assembly, and a signal conditioning circuit 12 is in communication with the position detection means.

In this embodiment, by providing the signal adjusting circuit 12, the output signal of the position detecting device 11 for detecting the position of the rotor of the reluctance motor is adjusted, that is, the signal of the detected position of the rotor of the reluctance motor is adjusted to improve the level jump of the detection signal, and/or the interference of the detection signal is filtered, so as to ensure the accuracy of the position detection, and the conventional position detecting device is adopted for detecting the position of the rotor of the reluctance motor, so that the position detection cost of the reluctance motor can be reduced, and the problem of high cost caused by adopting a code disc mode for detection is avoided.

The position detection device 11 may adopt a conventional position detection device, such as a hall detection mode or a single-grating detection mode, and the detection principle of the specific position is the same as that in the prior art, which is not limited and described herein.

The embodiment of the utility model provides a food preparation machine switched reluctance motor's position detection circuit adopts position detection device + signal adjusting circuit's mode for detect reluctance motor rotor position, and adjustment position detection device output signal can ensure that the position detection is accurate, and compares in current code wheel mode, and the cost advantage is obvious.

Further, in the above-described embodiment, the signal adjusting circuit 12 may be a level-triggered circuit, and when the output signal of the position detecting circuit 11 reaches a preset threshold, the output of the signal adjusting circuit 12 changes.

In this embodiment, the output signal (position detection signal) of the position detection circuit 11 passes through the signal adjustment circuit 12 triggered by the level, so that the level abrupt change state can be improved, interference can be effectively filtered, and accurate position detection is ensured.

Specifically, the signal adjusting circuit 12 is a level-triggered circuit, that is, the signal adjusting circuit 12 has a level-triggered characteristic, so that interference can be effectively filtered out, and accurate position detection is ensured. The level trigger characteristic means that when the input signal is at a preset level, for example, a high level "1" or a low level "0", the trigger state of the signal adjusting circuit 12 changes, otherwise, the trigger state of the signal adjusting circuit 12 remains unchanged.

In addition, when the output signal of the position detection circuit 11 reaches the preset threshold, the output of the signal adjustment circuit 12 changes, that is, the signal adjustment circuit 12 has positive and negative threshold characteristics, and can perform abrupt input, so that the level abrupt change state can be improved, and the position detection accuracy can be ensured. The positive and negative threshold characteristics refer to that for two input signals with different changing directions of negative decreasing and positive increasing, the preset threshold for the trigger state change of the signal adjusting circuit 12 has different threshold voltages.

Specifically, the preset threshold may include a positive threshold voltage and a negative threshold voltage, the input voltage that changes the state of the signal conditioning circuit 12 during the process of the input signal rising from the low level to the high level is referred to as the positive threshold voltage, and the input voltage that changes the state of the signal conditioning circuit 12 during the process of the input signal falling from the high level to the low level is referred to as the negative threshold voltage.

Optionally, the signal adjusting circuit 12 may be a nand gate array including M nand gates, where M is an integer greater than 1; the input of each nand gate is connected to the output of the position detection device 11.

In this embodiment, the signal adjusting circuit 12 may adopt a nand gate array to implement the level triggering characteristic and the positive and negative threshold characteristic of the signal adjusting circuit 12, so as to adjust the output signal of the position detecting circuit 11.

Optionally, the signal conditioning circuit may be a nand schmitt trigger. The implementation principle of the nand schmitt trigger is the same as that of the prior art, and this embodiment is not described herein again.

The embodiment of the utility model provides a position detection circuit of food preparation machine switched reluctance motor, signal conditioning circuit adopt the circuit that the level triggered, have the level and trigger the characteristic first, can effectively filter the interference; and secondly, the sensor has positive and negative threshold characteristics, and can improve the steep change state of the level, thereby ensuring accurate position detection.

Further, in the above-described embodiment, the position detection device 11 may include N pairs of grating members, N being an integer greater than 1; each pair of grating assemblies comprises two gratings, and the output end of each grating is communicated with the input end of one NAND gate.

In this embodiment, the position detection device 11 may detect the position by using a grating detection method, and the grating is a non-magnetic detection element, so that the grating is not affected by magnetic interference, and the magnetic interference of the motor can be eliminated. And the grating detection is adopted to compare with the rising characteristic of the Hall element, the level mutation of the grating is obvious, namely dV/dt is large enough, and the abnormity of the main control chip for collecting the rising edge can be filtered.

In addition, in the embodiment, the position is detected by adopting a mode of grating detection and a signal adjusting circuit, so that the interference in the signal can be eliminated, and the problem that the control is out of sequence or abnormally switched on due to the fact that the interference cannot be effectively filtered by single grating detection is solved.

In addition, the position is detected by adopting a grating detection and logic NAND Schmitt trigger mode, so that the cost can be reduced, and compared with the position detection by a code disc, the cost is lower. And secondly, the edge detectability can be improved, and compared with the Hall, the grating mutation and the mutation of the logic NAND gate Schmitt trigger are more obvious and are not influenced by the rotating speed.

Optionally, when the signal adjusting circuit 12 is a nand gate array including M nand gates, the value of M matches the number of the gratings. When the NAND gates are connected with the gratings in a one-to-one correspondence mode, the value of M is the same as the number of the gratings.

Further, in the above embodiment, each rotor salient pole is provided with a shutter, when the grating is not shielded by the shutter, the grating outputs a high level, and the signal adjusting circuit outputs a high level; when the grating is shielded by the light chopper, the grating outputs a low level, and the signal adjusting circuit outputs a low level.

Specifically, fig. 2 is the structure diagram that the grating that the embodiment of the utility model provides detected, fig. 3 is the utility model provides a structure diagram that is connected with non-gate array in grating and the signal conditioning circuit, as shown in fig. 2 and fig. 3, G1 and G2 are the grating respectively, R1 and R3 are the current-limiting resistor of the luminous end of grating respectively, R2 and R4 are pull-up resistance respectively, stable output, C1 and C3 are filter capacitance respectively. After the power is on, the light-emitting end of the grating normally emits light, each rotor salient pole is provided with a light chopper, when the grating is not blocked by the light chopper on the rotor salient pole, light passes through the gap to enable the conducting end to be conducted, and 1A outputs high level. When the grating is blocked by the light chopper on the salient pole of the rotor, light cannot penetrate to the conducting end, the conducting end is cut off, and 1A outputs low level.

In this embodiment, when the rotor salient pole rotates for one cycle, the number of times that the grating is conducted determines the position of the rotor of the reluctance motor, and the specific implementation principle is the same as that in the prior art, which is not repeated herein. In fig. 3, U1 is an nand gate array, and the truth table of outputs of 1A and S1 is shown in table 1 below:

TABLE 1

Further, in the above embodiment, the two gratings in each pair of grating assemblies form a first preset angle therebetween. Optionally, the first predetermined angle may be 75 °

Further, in the above embodiment, a second preset angle is formed between the two rotor salient poles in the rotor assembly, and the second preset angle is different from the first preset angle. Alternatively, the second preset angle may be 60 °.

In this embodiment, the angle between the two gratings is different from the angle between the two rotor salient poles, so that the gratings can be conducted when the rotor salient poles rotate for one cycle, and the position of the rotor can be detected.

For example, the present embodiment may detect 8/6 switched reluctance motors having 8 outer windings (stator windings) with 6 rotor salient poles. Each rotor protrusion is provided with a light shield, the angle difference between the two rotor protrusions can be 60 degrees, and the angle difference between the two gratings can be 75 degrees.

Specifically, fig. 4 is a motor state transition diagram provided by the embodiment of the present invention, and fig. 5 is a signal change diagram corresponding to fig. 4, as shown in fig. 4 and fig. 5, fig. 4 includes four motor states: state 1, state 2, state 3 and state 4, the rotor position in each state being the current position, when the motor rotates counterclockwise, the next state of the current position changes, corresponding to S1, S2 in the graph of fig. 5, from 01 to 11, when the stator salient poles and the rotor salient poles are aligned at D.

And if the rotor is continuously kept in the anticlockwise rotating state, the phase B needs to be switched on, and the rotor is closed according to the minimum path of the magnetic resistance, so that the rotor keeps anticlockwise torque. At the moment, the C phase needs to be kept in a turn-off state, the C phase is turned off at the moment because the C phase is turned on last time, and continuous follow current is realized because the inductance of the stator winding does not change suddenly.

In this embodiment, corresponding to fig. 4 and 5, the corresponding positions when the motor rotates counterclockwise and the phase sequence required to be switched on can be shown in table 2.

TABLE 2

S1	S2	Open phase	Follow current phase	Aligned phase
					1	1	B	C	D
1	0	A	B	C
					0	0	D	A	B
0	1	C	D	A

Corresponding to fig. 4 and 5, based on the same principle of counterclockwise rotation of the motor, it can be derived that the corresponding position is obtained when the motor rotates clockwise, and the phase sequence to be switched on can be shown in table 3.

TABLE 3

S1	S2	Open phase	Follow current phase	Aligned phase
					1	1	A	D	C
1	0	D	C	B
					0	0	C	B	A
0	1	B	A	D

As shown in table 2 or table 3, the rotor position can be quickly located by the rotor position detecting device, and the current on the corresponding rotor salient pole is turned on and off by the corresponding phase sequence, so as to achieve the purpose of controlling the rotation of the switched reluctance motor.

The embodiment of the utility model provides a food preparation machine switched reluctance motor's position detection circuit compares with prior art, has following beneficial effect: 1. the position detection device for detecting the position of the rotor by the grating is provided, so that the identifiability of the rising edge can be improved; 2. a multi-stage NAND gate filter circuit is provided, so that common mode interference of signals is effectively removed; 3. the scheme of replacing a Hall element by a grating is provided, so that the interference of rotating electromagnetism of the motor to the detection element is reduced; 4. a grating + NAND gate array scheme is provided, and the position detection cost is reduced.

In the description of the present invention, it should be noted that the terms "upper", "lower", "one side", "the other side", "one end", "the other end", "side", "opposite", "four corners", "periphery", "mouth" word structure "and the like indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings, and are only for convenience of description and simplification of the description, but do not indicate or imply that the structure referred to has a specific orientation, is constructed and operated in a specific orientation, and thus, is not to be construed as limiting the present invention.

In the description of the embodiments of the present invention, unless otherwise explicitly specified or limited, the terms "connected," "directly connected," "indirectly connected," "fixedly connected," "mounted," and "assembled" are to be construed broadly and may, for example, be fixedly connected, detachably connected, or integrally connected; the terms "mounted," "connected," and "fixedly connected" may be directly connected or indirectly connected through intervening media, or may be connected through two elements. The specific meaning of the above terms in the present invention can be understood in specific cases to those skilled in the art.

Although the embodiments of the present invention have been described above, the description is only for the convenience of understanding the present invention, and the present invention is not limited thereto. It will be understood by those skilled in the art that various changes in form and details may be made therein without departing from the spirit and scope of the invention as defined by the appended claims.

Claims (10)

1. A position sensing circuit for a switched reluctance motor of a food processor, the switched reluctance motor comprising a stator assembly, a rotor assembly, and a position sensing circuit, the position sensing circuit comprising: the position detection device is used for detecting the position of the rotor of the reluctance motor, and the signal adjusting circuit is used for adjusting the output signal of the position detection device;

the position detection device is arranged on the rotor assembly, and the signal adjusting circuit is communicated with the position detection device.

2. The position detection circuit of claim 1, wherein the signal conditioning circuit is a level-triggered circuit, and wherein the output of the signal conditioning circuit changes when the output signal of the position detection circuit reaches a preset threshold.

3. The position detection circuit of claim 2, wherein the signal conditioning circuit is a nand gate array comprising M nand gates, M being an integer greater than 1; the input end of each NAND gate is communicated with the output end of the position detection device.

4. The position detection circuit of claim 3, wherein the signal conditioning circuit is a NAND Schmitt trigger.

5. The position detection circuit according to claim 3 or 4, wherein the position detection device comprises N pairs of grating members, N being an integer greater than 1;

each pair of grating assemblies comprises two gratings, and the output end of each grating is communicated with the input end of one NAND gate.

6. The position detection circuit of claim 5, wherein the value of M matches the number of gratings.

7. The position sensing circuit of claim 5, wherein the two gratings in each pair of grating elements are at a first predetermined angle therebetween.

8. The position sensing circuit of claim 7, wherein a second predetermined angle exists between two rotor salient poles in the rotor assembly, and the second predetermined angle is different from the first predetermined angle.

9. The position sensing circuit of claim 8, wherein the first predetermined angle is 75 ° and the second predetermined angle is 60 °.

10. The position detection circuit according to claim 8, wherein a shutter is provided on each of the rotor salient poles, the shutter outputs a high level when the shutter is not shielded by the shutter, and the signal adjustment circuit outputs a high level; when the grating is shielded by the light chopper, the grating outputs a low level, and the signal adjusting circuit outputs a low level.

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