CN201569663U - Brushless DC motor speed measurement device based on hall element - Google Patents

Abstract

The utility model relates to a brushless DC motor speed measurement device based on a hall element, which comprises a hall signal processing unit, a singlechip processing unit and an external interface unit, wherein the hall signal processing unit receives a hall signal input by the hall element of a brushless DC motor, and the hall signal is output to the singlechip processing unit after filtering and shaping; the singlechip processing unit carries out core algorithm processing of the signal input by the hall signal processing unit, and then outputs speed information through the external interface unit; and the external interface unit is provided with 5V and 3.3V logic level external output serial interfaces. The utility model utilizes the speed measuring function of the hall element, designs a special speed measuring module, transfers information through a serial port, and thereby facilitating the system integration, better solving the problem of speed measurement fluctuation, and having a failure report mechanism and better generality.

Description

A kind of brshless DC motor speed measuring device based on Hall element

Technical field

The utility model relates to a kind of motor speed measuring technology, a kind of specifically brshless DC motor speed measuring device based on Hall element.

Background technology

Permanent-magnet brushless DC electric machine has good speed adjusting performance, as stepless speed regulation, speed-regulating range width, high-level efficiency etc., is widely used in recent years in the underwater robot propeller drive system.Consider the design of simplifying thruster physical construction, the signal of the hall detector of general direct employing motor self carries out position and velocity feedback, does not increase other position and speed detecting element.Adopt hall signal that rotating speed is measured two kinds of methods of common employing: a kind of one road hall signal that is to use is measured, because one-channel signal resolution is lower, feedback cycle is long, is used in the High-speed Control field usually; A kind of is to utilize three road hall signals, by logical circuit or algorithm, produces 6 times to the frequency-doubled signal of one road hall signal frequency, then it is measured.But these two kinds of methods are positioned with strict requirement to Hall element on the motor stator circumference, when Hall element was positioned with error on the motor stator circumference, the width of adjacent two positive pulses will be inconsistent, cause the fluctuation of speed that records very big.

The utility model content

At above shortcomings part in the prior art, the technical problems to be solved in the utility model provides a kind of modularization, interface is simple and test the speed the less brshless DC motor speed measuring device based on Hall element of fluctuation.

To achieve these goals, the technical solution adopted in the utility model is:

The utility model comprises hall signal processing unit, single-chip microcomputer processing unit and external interface unit based on the brshless DC motor speed measuring device of Hall element, wherein the hall signal processing unit receives the hall signal of the Hall element input of brshless DC motor, carries out exporting the single-chip microcomputer processing unit to behind the filter shape; After the signal that the single-chip microcomputer processing unit is imported the hall signal processing unit carries out the core algorithm processing, by external interface unit output speed information; The external interface unit has 5V and the 3.3V logic level is externally exported serial line interface.

Described hall signal processing unit has rc filter circuit and schmitt inverter, wherein the input end of rc filter circuit is connected to the hall signal of Hall element input, output terminal is connected to the input end of schmitt inverter, and the signal of schmitt inverter after with shaping exports the single-chip microcomputer processing unit to.

The utility model also has the logic level converter unit, comprise Voltage stabilizing module and logic level transition module, Voltage stabilizing module converts outer power supply source to working power that the logic level transition module needs, and the logic level transition module is externally exported serial line interface for the external interface unit provides logic level.

The utility model compared with prior art has more following advantage:

1. function modoularization, interface is simple.The function that the utility model will utilize Hall element to test the speed extract, and has designed special speed measuring module, externally transmits information by serial ports, is convenient to the integrated of system.

2. the fluctuation of testing the speed is less.Original frequency multiplication speed-measuring method is improved, and the problem that is positioned with error at common brshless DC motor Hall element on the motor stator circumference has proposed solution, thereby preferably resolves the problem of the fluctuation of testing the speed.

3. possesses Trouble Report mechanism.When Hall element goes wrong, module can be uploaded failure message when speed measuring function went wrong, and speed measuring module possesses auto restore facility when of short duration fault is eliminated, and uploads correct velocity information.

4. versatility is better.This utility model versatility is stronger, also can be used for the various common brshless DC motors field of testing the speed.

Description of drawings

Fig. 1 is the utility model structured flowchart;

Fig. 2 is the utility model integrated circuit schematic diagram;

Fig. 3 A is the control method main program flow chart that utility model adopts;

Fig. 3 B is an interrupt request process flow diagram flow chart in the control method that adopts of utility model;

Fig. 4 is the timer interrupt service routine process flow diagram in the control method of the utility model employing;

Fig. 5 is the state processing unit program flow diagram in the control method of the utility model employing.

Embodiment

Below in conjunction with accompanying drawing the utility model is described in further detail.

As shown in Figure 1, the utility model comprises hall signal processing unit, single-chip microcomputer processing unit and external interface unit based on the brshless DC motor speed measuring device of Hall element, wherein the hall signal processing unit receives the hall signal of the Hall element input of brshless DC motor, carries out exporting the single-chip microcomputer processing unit to behind the filter shape; After the signal that the single-chip microcomputer processing unit is imported the hall signal processing unit carries out the core algorithm processing, by external interface unit output speed information; The external interface unit has 5V and the 3.3V logic level is externally exported serial line interface.

Described single-chip microcomputer processing unit is realized the process of testing the speed by the realization of the responsible core algorithm of operation by the control program of operation motor measurement mechanism.

The hall signal processing unit has rc filter circuit and schmitt inverter, wherein the input end of rc filter circuit is connected to the hall signal of Hall element input, output terminal is connected to the input end of schmitt inverter, and the square-wave signal of the standard that schmitt inverter forms after with filter shape exports the single-chip microcomputer processing unit to.

Also has the logic level converter unit, comprise Voltage stabilizing module and logic level transition module, Voltage stabilizing module converts outer power supply source to working power that the logic level transition module needs, and the logic level transition module is externally exported serial line interface for the external interface unit provides logic level.

The external interface unit comprises 5V logic level serial line interface, 3.3V level logic serial line interface, and power interface and hall signal interface, the utility model motor speed measuring device externally carries out serial communication by the level logic serial line interface, and power interface connects the 5V power supply; The hall signal interface connects 5 lines of motor Hall element output.

The electrical schematic diagram of the utility model motor speed measuring device as shown in Figure 2, the 5V power supply is given whole motor speed measuring device power supply by the 4th, 5 pins of the 1st terminal J1, the 5V power supply is transformed into 3.3V through Voltage stabilizing module U3 (SPX1117-3.3V), gives the 1st, 2 logic level transition U12_1, U12_2 power supply; Hall signal HA, HB and HC are through 1,2 and 3 pins of the 1st terminal J1, through the 1st～6 resistance R 1～R6 with after being integrated in the filtering shaping circuit of the 1st～6 inverter modules U1A～U1F composition in the 74HC14 schmitt inverter, be linked into the PA mouth of the one-chip computer module U2 (ATMEGA8515L) of single-chip microcomputer processing unit then.The serial ports pin of one-chip computer module U2 is connected to the pin of the 2nd terminal J2, externally carries out serial communication, is output as the 5V logical signal.Microcontroller serial port is leaded molded to carry out being connected to after the level translation pin of the 3rd terminal J3 through the 1st, 2 logic level transition module U12_1, U12_2, externally carries out serial communication, output be the 3.3V logical signal.

Shown in Fig. 3 A, 3B, the control method that the utility model adopts may further comprise the steps:

Start-up routine carries out entering recurrent state behind the device initialize;

Serial ports interrupt request or timer interrupt request have been judged whether;

When the serial ports interrupt request, carry out the serial ports interrupt service routine;

When the timer request, carry out the timer interrupt service routine;

If the finish command is arranged, end loop control procedure then.

Described interrupt handling routine is mainly carried out 2 interrupt service routines, is respectively interruption of 50us timer and serial ports and interrupts.In the timer interrupt service routine, go out rotary speed information according to the state computation of hall signal; In the serial ports interrupt service routine, realize that described speed measuring device and external microcontroller carry out the function of handshake communication.

As shown in Figure 4, described timer interrupt service routine may further comprise the steps:

Detect the state of hall signal;

Enter the processing unit of corresponding state according to above-mentioned signal condition, carry out the calculating and the processing of motor speed;

Preserve the current state value, withdraw from interruption.

The following formula that passes through of motor speed calculates:

$n_i=\frac{60f_0}{\underset{j=i}{\overset{i-{6N}_0+1}{\mathrm{\Σ}}}{T}_j}---\left(3\right)$

F wherein ₀Be the clock frequency of counter, T _i=m _i-m _I-1, m _iBe the reading of i next state conversion hour counter, N ₀Be the motor pole logarithm, j is an intermediate variable.

As shown in Figure 5, the state of described hall signal is 6, corresponding 6 processing units, and wherein the 1st state processing unit 0 program idiographic flow is:

Current state value and preceding state value (st0) are compared, if both equate that the size and Orientation of rotating speed remains unchanged;

If preceding state value equates that with preorder state value (st5) it is forward that the size of calculating rotating speed is provided with direction;

If preceding state value equates with the postorder state value (st1) of current state value, calculate the size of rotating speed, direction is set for reverse;

If for other values then be set at malfunction.

State st0-st5 respectively with code 101,100,110,010,011,001 is corresponding.

The program circuit of the program circuit of other state processing unit and the 1st state processing unit is similar, only need just can according to the modification of current state value its preorder state value and postorder state value, for example for the 2nd state processing unit 1, the current state value is st1, its preorder state value is st0,, its postorder state value is st2, and the like.

Described serial ports interrupt service routine may further comprise the steps:

The character (present embodiment is character " # ") that the expression communication that the external microcontroller transmission is set begins represents to begin to receive data for one-chip computer module U2;

After one-chip computer module U2 receives " # ", the upper byte of beginning transmission speed data;

After external microcontroller received upper byte, the expression that transmission is set began to receive the character (present embodiment is character " 1 ") of upper byte data and gives one-chip computer module U2, and the expression upper byte is received, begins to accept low byte;

After one-chip computer module U2 receives " 1 ", send low byte;

After external microcontroller is received low byte, the upper byte low byte is combined as complete velocity information, the information of the size of extraction rate, direction and fault then, sign off.

Adopt two bytes to represent velocity information, the direction of the 1st bit representation motor rotation, the 2nd bit representation malfunction that tests the speed, the size of back 14 bit representation speed, speed maximal value are 16837 to change per minutes.

The ultimate principle of the utility model motor speed measuring is: brshless DC motor generally adopts the rotor position detector of Hall switch type, carries out motor commutation control with hall sensor signal usually.Through shaping, it is three the tunnel to differ 120 ° low-frequency pulse that the hall signal sensor sends HA, HB, HC signal, and this three road signal has been formed 6 different codes in 360 ° of electrical angles, form six kinds of different states, these six codes are 101,100,110 successively, 010,011,001.Change successively according to this order when just changeing, change successively against this order during counter-rotating, so the information that this three road signal is comprising rotating speed and turning to.If the motor pole logarithm is N ₀, then motor whenever turns around and just has N ₀Organize 6 different states, setting a clock frequency is f ₀Counter, motor whenever runs to a state, the value of recording counter is m _i, then motor rotating speed at this moment is

$n_i=\frac{{60f}_0}{m_i-m_{i-{6N}_0}}---\left(1\right)$

The specific procedure design philosophy of described speed measuring device is: when considering problems such as counter overflows, and numerical value is excessive, can be to be out of shape to formula (1), because

$m_i-m_{i-{6N}_0}=\underset{j=i}{\overset{i-6N_0+1}{\mathrm{\Σ}}}(m_j-m_{j-1})---\left(2\right)$

Make T _i=m _i-m _I-1, (1) formula is can be changed into

$n_i=\frac{{60f}_0}{\underset{j=i}{\overset{i-{6N}_0+1}{\mathrm{\Σ}}}{T}_j}$ (3)

Must reduce the summation number of times in order to accelerate computing velocity, adopt moving window summation algorithm 6N ₀Inferior summation is converted into twice summation, and the Processing Algorithm of calculating motor speed is as follows:

(1) overall array A[6N of definition ₀], global variable bcnt, atop, sum, local variable T, and they are initialized as 0, the reading of current counter is m _i

(2) carry out T=m _i-bcnt, bcnt=m _i, sum=sum-A[atop]+T, A[atop]=T, if atop=atop+1 is atop=6N ₀, atop=0 then, present speed=60f ₀/ sum; m _iValue for recording counter; N ₀Be the motor pole logarithm; f ₀Clock frequency for counter;

(3) in the measurement of motor speed, because the pulsation of rotating speed itself, random disturbance exists, and the rotating speed that records is averaged value filtering, will reach reasonable effect.

Claims (3)

1. brshless DC motor speed measuring device based on Hall element, it is characterized in that: comprise hall signal processing unit, single-chip microcomputer processing unit and external interface unit, wherein the hall signal processing unit receives the hall signal of the Hall element input of brshless DC motor, carries out exporting the single-chip microcomputer processing unit to behind the filter shape; After the signal that the single-chip microcomputer processing unit is imported the hall signal processing unit carries out the core algorithm processing, by external interface unit output speed information; The external interface unit has 5V and the 3.3V logic level is externally exported serial line interface.

2. by the described brshless DC motor speed measuring device of claim 1 based on Hall element, it is characterized in that: described hall signal processing unit has rc filter circuit and schmitt inverter, wherein the input end of rc filter circuit is connected to the hall signal of Hall element input, output terminal is connected to the input end of schmitt inverter, and the signal of schmitt inverter after with shaping exports the single-chip microcomputer processing unit to.

3. by the described brshless DC motor speed measuring device of claim 1 based on Hall element, it is characterized in that: also have the logic level converter unit, comprise Voltage stabilizing module and logic level transition module, Voltage stabilizing module converts outer power supply source to working power that the logic level transition module needs, and the logic level transition module is externally exported serial line interface for the external interface unit provides logic level.

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