CN110308690A - Design method of DSP logic control program for brushless DC motor based on Petri net - Google Patents

Abstract

The design method of the present invention relates to a kind of brshless DC motor DSP logic control program based on Petri network, pass through the Hall sensor and course changing control variable modeling to brshless DC motor, the Petri network of power tube is obtained, Petri net model is intuitive and easy to understand, and is easy to analyze.The present invention, up to nomography, calculates the state set of brshless DC motor dynamical system by Petri network, and is verified one by one according to trapezoidal commutation logic, whether specification is met, if not meeting, the Petri net model of system is redesigned, avoids the logic error in program.The present invention provides brshless DC motor logic control mathematic(al) representation, lays the groundwork for the design of DSP logic control program, and the control of mathematic(al) representation description logic is more rigorous and clear.

Description

Design method of DSP logic control program for brushless DC motor based on Petri net

technical field

The present invention relates to the field of DSP logic control of brushless direct current motor, more specifically, relates to a design method of DSP logic control program of brushless direct current motor based on Petri net, so as to ensure the correctness and reliability of the logic program.

Background technique

A common DC brushless motor consists of a motor body, a power drive circuit and a position sensor. The stator of the motor body is an armature winding, and the material of the rotor is a permanent magnet. The rotor generates a rotating magnetic field inside the motor, and the armature winding is energized in a corresponding logical order to generate a corresponding rotating magnetic field. The two magnetic fields interact to generate a rotating torque, realizing brushless normal operation of the motor. The position sensor detects the position of the motor rotor in real time, converts the magnetic position signal of the rotor into an electrical signal and transmits it to the controller, and the controller determines the commutation information of the motor in the drive circuit according to the obtained rotor position.

The design and debugging of the traditional brushless DC motor DSP logic control program is cumbersome. Verification and testing usually rely on manual repeated debugging and trial and error. It is difficult to avoid logic errors in the program and obtain a reliable logic control program.

Contents of the invention

The purpose of the present invention is to overcome the deficiencies in the prior art, provide a kind of convenient verification, avoid program logic error, to obtain the design method of the brushless DC motor DSP logic control program based on Petri net of reliable logic control program.

Technical scheme of the present invention is as follows:

A design method of a brushless DC motor DSP logic control program based on Petri net, comprising the steps:

1) Establish the Petri net model of logic control of brushless DC motor;

2) Establish a dynamic behavior model of brushless DC motor based on Petri net reachability graph;

3) Design the DSP logic control program of brushless DC motor through Petri net.

As preferably, step 1) is specifically as follows:

1.1) Establish the Petri net model of the Hall sensor: use a pair of places and Describe the high-level signal and low-level signal of the Hall sensor respectively, using a pair of transitions and Describe the Hall sensor switching from low level to high level and the Hall sensor switching from high level to low level;

1.2) Establish the Petri net model of the motor rotation direction control variable: use a pair of places and Describe the forward rotation and reverse rotation of the motor separately; use a pair of transitions and Respectively describe the switching of the motor from reverse to forward rotation and the switching of the motor from forward to reverse rotation;

1.3) Establish a Petri net model for each power tube: use a pair of places and Describe the on-state and off-state of the power tube respectively; formalize the trapezoidal commutation logic expression of the power tube into a disjunctive paradigm, describe each conjunction logic as a transition, and the input of the transition corresponds to the conjunction logic expression In the formula, the logic variable corresponds to the place node, and the output of the transition is the on or off place node corresponding to the power transistor.

As a preference, step 2) is specifically: according to the Petri net reachable graph algorithm, calculate the state set of the brushless DC motor dynamic system, and verify one by one according to the trapezoidal commutation logic, whether it meets the specification, if not, redesign the Petri net model .

Preferably, in step 2), in the initial state, all signals are in the low level or off state by default, and the initial identification is obtained as the corresponding place token Token.

As preferably, step 3) is specifically as follows:

3.1) With the help of the Petri net of each Hall sensor, according to its place name and In the DSP control program, define the input variable corresponding to the sensor as H _i ;

3.2) With the help of the Petri net of the steering control variable, according to the place name and In the DSP control program, define the input variable corresponding to the motor rotation direction control as D;

3.3) With the help of the Petri net of the power tube variable, according to its place name and In the DSP control program, define the input variable corresponding to the power tube as VT _i ;

3.4) With the help of the Petri net of each power tube, design the DSP logic control program of the brushless DC motor according to the execution logic of each transition.

The beneficial effects of the present invention are as follows:

The design method of the brushless DC motor DSP logic control program based on the Petri net of the present invention obtains the Petri net of the power tube by modeling the Hall sensor and the steering control variable of the brushless DC motor, and the Petri net model is intuitive and easy understandable and easy to analyze.

The present invention calculates the state set of the dynamic system of the brushless DC motor through the Petri net reachability graph algorithm, and verifies one by one according to the trapezoidal commutation logic whether it conforms to the specification. If not, the Petri net model of the system is redesigned to avoid logic error.

The invention provides a mathematical expression for the logic control of the brushless direct-current motor, paves the way for the design of the DSP logic control program, and the mathematical expression describes the logic control more rigorously and clearly.

Description of drawings

Fig. 1 is a schematic circuit diagram of a brushless DC motor drive circuit;

Fig. 2 is a state schematic diagram of Hall sensor signal output;

Fig. 3 is a state schematic diagram of brushless DC motor commutation;

Fig. 4 is the schematic diagram of the Petri net model of Hall sensor;

Fig. 5 is the schematic diagram that turns to the Petri net model of control variable D;

Fig. 6 is the schematic diagram of the Petri net model of power tube VT ₃ ;

Figure 7 is a state reachable diagram of the DSP logic control program of the brushless DC motor.

Detailed ways

The present invention will be further described in detail below in conjunction with the accompanying drawings and embodiments.

The present invention solves the problems in the prior art that the design and debugging are cumbersome, verification and detection usually rely on repeated manual debugging and trial and error, it is difficult to avoid logical errors in the program, and it is difficult to obtain a reliable logic control program. A design method of DSP logic control program for brushless DC motor based on Petri net to ensure the correctness and reliability of the logic program.

The design method of the brushless DC motor DSP logic control program based on Petri net of the present invention comprises the steps:

1) Establish the Petri net model of logic control of brushless DC motor;

2) Establish a dynamic behavior model of brushless DC motor based on Petri net reachability graph;

3) Design the DSP logic control program of brushless DC motor through Petri net.

Wherein, step 1) is specifically as follows:

1.1) Establish the Petri net model of the Hall sensor:

Describe each Hall sensor as a ring consisting of 2 places and 2 transitions, and use a pair of places and Describe the high-level signal and low-level signal of the Hall sensor respectively, using a pair of transitions and Describe the Hall sensor switching from low level to high level and the Hall sensor switching from high level to low level;

1.2) Establish the Petri net model of the motor rotation direction control variable:

Input the control input of the motor rotation direction to describe the ring composed of 2 places and 2 transitions, and use a pair of places and Describe the forward rotation and reverse rotation of the motor separately; use a pair of transitions and Respectively describe the switching of the motor from reverse to forward rotation and the switching of the motor from forward to reverse rotation;

1.3) Establish the Petri net model of each power tube:

For each power tube, use a pair of place and Describe the on-state and off-state of the power tube respectively; formalize the trapezoidal commutation logic expression of the power tube into a disjunctive paradigm, describe each conjunction logic as a transition, and the input of the transition corresponds to the conjunction logic expression In the formula, the logic variable corresponds to the place node, and the output of the transition is the on or off place node corresponding to the power transistor.

Step 2) is specifically: according to the Petri net reachable graph algorithm, calculate the state set of the brushless DC motor dynamic system, and verify one by one according to the trapezoidal commutation logic, whether it meets the specification, if not, redesign the Petri net model. Among them, in the initial state, the default is that all signals are in the low level or off state, and the initial identification is obtained as the corresponding place token Token.

Step 3) is as follows:

3.1) With the help of the Petri net of each Hall sensor, according to its place name and In the DSP control program, define the input variable corresponding to the sensor as H _i ;

3.2) With the help of the Petri net of the steering control variable, according to the place name and In the DSP control program, define the input variable corresponding to the motor rotation direction control as D;

3.3) With the help of the Petri net of the power tube variable, according to its place name and In the DSP control program, define the input variable corresponding to the power tube as VT _i ;

3.4) With the help of the Petri net of each power tube, design the DSP logic control program of the brushless DC motor according to the execution logic of each transition.

Example

As shown in FIG. 1 , in the drive circuit of the brushless DC motor of this embodiment, the stator windings of the motor are connected in star form, and the inverter adopts a three-phase full-bridge inverter circuit, and the power supply mode is two-two conduction. The rotor position is detected by the Hall sensor, the pulse width signal output by the sensor is 180° electrical angle, and the phase difference of the three Hall signal outputs is 120°, as shown in Figure 2 and Figure 3. The controller processes the position signal and outputs the commutation information, and drives the VT ₁ ~ VT ₆ power tubes on the three bridge arms of the inverter circuit. The relationship between the state of the Hall sensor and the commutation is shown in the following table:

The design method of the described brushless DC motor DSP logic control program based on Petri net, comprises the following parts:

1) Establish the Petri net model of the Hall sensor

As shown in Figure 4, with a pair of places and Describe the high-level signal and low-level signal of the Hall sensor respectively, using a pair of transitions and Respectively describe the Hall sensor switching from low level to high level and the Hall sensor switching from high level to low level.

2) Establish the Petri net model of the motor rotation direction control variable

As shown in Figure 5, with a pair of places and Describe the forward rotation and reverse rotation of the motor separately; use a pair of transitions and Respectively describe the switching of the motor from reverse to forward rotation and the switching of the motor from forward to reverse rotation.

3) Establish the Petri net model of each power tube

use a pair of warehouses and Describe the on-state and off-state of the power tube respectively; formalize the trapezoidal commutation logic expression of the power tube into a disjunctive paradigm, describe each conjunction logic as a transition, and the input of the transition corresponds to the conjunction logic expression In the formula, the logic variable corresponds to the place node, and the output of the transition is the on or off place node corresponding to the power transistor. As shown in Figure ₆ , taking the power tube VT3 as an example (other power tubes are the same, those skilled in the art can deduce it according to the description _of the power tube VT3, and will not repeat it), the input of the transition is output as and VT ₃ is turned on under 4 transition conditions, and is turned off under 4 transition conditions.

4) Establish the logic control state reachable graph of brushless DC motor based on Petri net

4.1) Through the Petri net model of the power tube, the input transition set and output transition set can be obtained as follows:

4.2) The specific form of each state representation in the state reachability diagram is as follows:

in, is 1, When it is 0, it means that the Hall sensor is a low-level signal; is 0, When it is 1, it means that the Hall sensor is a high-level signal; is 1, When it is 0, it means the motor reverses, is 0, When it is 1, it means the motor rotates forward; is 1, When it is 1, it means that the power tube is off. is 0, When it is 1, it means that the power tube is in the conduction state.

4.3) Take the state m ₀ shown in Figure 7 as an example (other states are the same, those skilled in the art can deduce it according to the description of the state m ₀ , and will not repeat it), m ₀ is a node represented by a dotted line, then, m ₀ is an input initial state, and the default is that all signals are low level or off, that is, m ₀ = (1,0,1,0,1,0,1,0,1,0,1,0 ,1,0,1,0,1,0,1,0) ^T .

m ₀ via transition Excited to any state of m ₁ , m ₃ , m ₅ , m ₇ , m ₉ , m ₁₁ , the motor rotates forward, and the rotation sequence is m ₁ →m ₃ →m ₅ →m ₇ →m ₉ →m ₁₁ ; m ₀ has changed Excited to any state of m ₂ , m ₄ , m ₆ , m ₈ , m ₁₀ , m ₁₂ , the motor reverses, and the rotation sequence is m ₂ →m ₄ →m ₆ →m ₈ →m ₁₀ →m ₁₂ .

According to the Petri net reachability graph, calculate the state set of the dynamic system of the brushless DC motor, and according to the trapezoidal commutation logic, substitute the signals into the logic expression one by one to verify whether it meets the specification, if not, redesign the Petri net model of the system.

5) Design the DSP logic control program of the brushless DC motor according to the Petri net of the power tube

5.1) With the help of the Petri net of each Hall sensor, according to its place name and In the DSP control program, define the input variable corresponding to the sensor as H _i ;

5.2) With the help of the Petri net of the steering control variable, according to the place name and In the DSP control program, define the input variable corresponding to the motor rotation direction control as D;

5.3) With the help of the Petri net of the power tube variable, according to its place name and In the DSP control program, define the input variable corresponding to the power tube as VT _i ;

5.4) With the help of the Petri net of each power transistor, according to the execution logic of each transition, design the DSP logic control program of the brushless DC motor, and write the assignment program instructions of the power transistor VT _i .

Taking VT ₃ as an example, the procedure is as follows:

"if VT ₃ == 0

VT ₃ ==! VT ₃ &&! H ₁ && H ₂ && H ₃ &&D;

VT ₃ ==! VT ₃ &&! H ₁ && H ₂ &&! H ₃ &&D;

VT ₃ ==! VT ₃ &&! H ₁ && H ₂ && H ₃ &&! D;

VT ₃ ==! VT ₃ &&! H ₁ && H ₂ &&! H ₃ &&! D;

else if VT ₃ ＝＝1

VT ₃ == VT ₃ &&! (H ₁ &&! H ₂ && H ₃ );

VT ₃ == VT ₃ &&! (!H1 &&! _H2 && _{H3 )} ;

VT ₃ == VT ₃ &&! (H ₁ && H ₂ &&! H ₃ );

VT ₃ == VT ₃ &&! (H ₁ &&! H ₂ &&! H ₃ );".

The above-mentioned embodiments are only used to illustrate the present invention, but not to limit the present invention. As long as it is based on the technical spirit of the present invention, changes and modifications to the above embodiments will fall within the scope of the claims of the present invention.

Claims (5)

1. A design method of a Petri network-based DSP logic control program of a brushless direct current motor is characterized by comprising the following steps:

1) establishing a Petri network model for logic control of the brushless direct current motor;

2) establishing a brushless direct current motor dynamic behavior model based on a Petri network reachability graph;

3) and designing a DSP logic control program of the brushless direct current motor through a Petri network.

2. The design method of the Petri net-based DSP logic control program of the brushless direct current motor according to claim 1, wherein the step 1) is specifically as follows:

1.1) establishing a Petri net model of the Hall sensor: using a pair of librariesAnddescribing the high and low level signals of a Hall sensor, respectively, using a pair of transitionsAndrespectively describing the switching of the Hall sensor from low level to high level and the switching of the Hall sensor from high level to low levelChanging;

1.2) establishing a Petri network model of a motor rotation direction control variable: using a pair of librariesAndthe forward rotation and the reverse rotation of the motor are respectively described; by a pair of transitionsAndthe switching of the motor from reverse rotation to forward rotation and the switching of the motor from forward rotation to reverse rotation are respectively described;

1.3) building a Petri net model of each power tube: using a pair of librariesAndrespectively describing the on state and the off state of the power tube; and the trapezoidal reversing logic expression of the power tube is formed into a disjunctive normal form, each conjunctive logic is described as a transition, the input of the transition corresponds to the base node corresponding to the logic variable in the conjunctive logic expression, and the output of the transition is the base node corresponding to the power tube which is switched on or switched off.

3. The design method of the Petri net-based DSP logic control program of the brushless direct current motor according to claim 1, wherein the step 2) is specifically as follows: and calculating a state set of the brushless direct current motor dynamic system according to a Petri network reachability graph algorithm, verifying one by one according to trapezoidal commutation logic to determine whether the state set meets the specification, and redesigning the Petri network model if the state set does not meet the specification.

4. The design method of the DSP logic control program of the Petri net-based brushless direct current motor according to claim 3, wherein in the step 2), all signals are in a low level or an off state by default in the initial state, and the initial identification is obtained as the Token marked by the corresponding library.

5. The design method of the Petri net-based DSP logic control program of the brushless direct current motor according to claim 1, wherein the step 3) is specifically as follows:

3.1) by means of a Petri network per Hall sensor, according to the name of its libraryAndin the DSP control program, defining the input variable corresponding to the sensor as H_i；

3.2) Petri Net with steering control variables, according to the name of its libraryAndin the DSP control program, defining an input variable corresponding to the motor rotation direction control as D;

3.3) Petri Net with Power tube variables, according to the name of its libraryAndin the DSP control program, defining the input variable corresponding to the power tube as VT_i；

And 3.4) designing a DSP logic control program of the brushless direct current motor by means of a Petri network of each power tube according to the execution logic of each transition.