RU121085U1 - EMBEDDED CONTROLLER OF ELECTRIC DRIVE PARAMETERS - Google Patents

Abstract

Built-in controller of parameters of an electric drive containing a DC or AC electric motor connected to the load through a controlled mechanical transmission, a control sensor built into the electric motor, a peak amplitude detector, the input of which is connected to a control sensor, a pulse shaper, the input of which is connected to the output of the peak amplitude detector, aperiodic link of the first order, the input of which is connected to the output of the peak amplitude detector, a nine-bit seven-segment sign indicator ALS356A, characterized in that an eight-bit ATmega8L microcontroller with a ten-bit ADC is introduced, FLASH program memory, EEPROM and SRAM data memory, the first line of the microcontroller port configured as input is connected to the output of the pulse shaper, the second line of the microcontroller port, configured as an ADC input, is connected to the output of the first order aperiodic link, and seventeen lines of microcontroller ports configured as output are connected y to a nine-digit seven-segment character display.

Description

The utility model relates to electrical engineering, and in particular to devices for the built-in control of electromechanical time constants of electric motors of constant and alternating currents and dead moves of mechanical transmissions of electric drives during their operation without dismantling mechanical transmissions and electric motors from products.

A well-known analogue is the RF Patent for utility model No. 77121, IPC Н02К 7/10, Н02Р 5/00. The device of the built-in control of the time constant of the electric motor and the standstill of the mechanical transmission of the electric drive / K. Ankudinov // Bull. No. 28 dated 10/10/2008, comprising: a mechanical transmission with a workload; a direct current drive electric motor, in the anchor winding of which a sensor is connected in series - active resistance with a value of two to three orders of magnitude less than the resistance of the armature winding; pulse shaper; aperiodic link of the first order; node for detecting voltage extremes; ATtiny28L eight-bit microcontroller and ALS329B four-digit seven-segment sign indicator.

The analogue has two main disadvantages:

- it is impossible to use an analogue for measuring the _deadlocks α _≈ and electromechanical time constants T _ED≈ mechanical transmissions of AC electric drives, although AC electric drives are widely used in the national economy and special equipment;

- in the analogue, only the numerical value of the dead stroke of the mechanical transmission of the DC electric drive α ₌ is displayed, and the numerical value of the electromechanical time constant of the DC motor T _{ED = is} not displayed, although this parameter is included in the transfer function of the electric drive and is determining in accuracy, speed and stability of the electric drive.

Known prototype - RF Patent for utility model No. 108237, IPC Н02К 7/10. Built-in controller of object parameters / Karpov EB, Ankudinov K.A., Ankudinov A.I. et al. // Bull. No. 25 dated 09/10/2011, comprising: a direct or alternating current electric motor connected to the load through a controlled mechanical transmission, a control sensor integrated in the electric motor, a peak amplitude detector, a pulse shaper, a first-order aperiodic link, a voltage extreme detection unit, an ATmega8515L eight-bit microcontroller with FLASH-memory programs, EEPROM- and SRAM-data memory and nine-digit seven-segment sign indicator ALS356A.

The prototype microcontroller’s algorithm is based on two equations:

where: Т _Э≃ is the time to reach the voltage extreme of the output signal of the first-order aperiodic link in the electric drive;

T _AZ - time constant of the aperiodic link of the first order;

T _ED≃ - electromechanical time constant of an electric motor of direct or alternating current;

k _≃ = U _1≃ / U _0≃ is the multiplicity of the starting voltage at the drive control sensor (the ratio of the amplitude of the exponential voltage component at the sensor U _1≃ at the time of starting the DC or AC motor to the constant voltage component at the sensor U _0≃ in steady state) ;

α _≃ is the dead stroke of a mechanical transmission of an electric drive of direct or alternating current;

Ω _H≃ - rated rotation speed of a direct or alternating current electric motor;

T _MX≃ - the time of selection of the _deadlock α _≃ mechanical transmission of the electric drive.

In the prototype, the microcontroller calculates according to a given algorithm:

- the electromechanical time constant of the electric motor of direct or alternating current T _ED≃ from the transcendental equation (1) and displays its value on the sign indicator;

- the dead stroke of the mechanical transmission of an electric drive of direct or alternating current α _≃ from the expression (2) and displays its value on the sign indicator.

The prototype is devoid of both disadvantages of the analogue, but it has its following disadvantages:

1. The systematic error of measuring and calculating the parameters of the electric drive T _≃ and α _{≃ in} principle can not be less than 0.39%. Atmel's eight-bit AVR microcontrollers of the Atiny family of Tiny and Mega families are used in the analogue and prototype, in which the EEPROM-, SRAM-data memory and general-purpose registers have an eight-bit basis, and all information processing occurs in eight-bit form, therefore, a systematic measurement and calculation error electric drive parameters is at least 0.39%.

2. The complexity and high cost of the prototype.

The proposed utility model, the built-in controller of the electric drive parameters, solves the problem of decreasing the systematic error of measuring and calculating the electromechanical time constant of the electric motor of constant or variable T _ED≃ and the dead-time of mechanical transmission of the electric drive α _≃ while reducing the complexity and cost of the device.

Let us pay attention to the fact that all Mega eight-bit AVR microcontrollers in their structure necessarily contain program FLASH memory, EEPROM and SRAM data memory, but not all have an analog-to-digital converter (ADC), and the prototype uses an outdated one ATmega8515L eight-bit microcontroller (before the introduction of the universal classification in 2003 - AT8515) that does not contain an ADC and has 40 pins. Some modern eight-bit Mega-Series AVR microcontrollers have a ten-bit ADC and this fact was used to develop a useful model. For example, the modern eight-bit ATmega8L microcontroller has 28 pins, a ten-bit ADC, program FLASH memory, EEPROM and SRAM data memory. To use the ten-bit ADC of the ATmega8L microcontroller, it is necessary to proceed from measuring the time in the prototype to measuring voltage - in a utility model, which will be done when describing the principle of operation of the proposed built-in controller of electric drive parameters.

The task is achieved by the fact that in the built-in parameter controller of the electric drive, containing an electric motor of direct or alternating current, connected to the load via a controlled mechanical transmission, a control sensor built into the electric motor, a peak amplitude detector, the input of which is connected to the control sensor, a pulse shaper, the input of which connected to the output of the peak amplitude detector, an aperiodic link of the first order, the input of which is connected to the output of the peak amplitude detector ora, nine-digit seven-segment sign indicator ALS356A, introduced an eight-bit ATmega8L microcontroller with a ten-bit ADC, FLASH program memory, EEPROM and SRAM data memory, the first line of the microcontroller port configured as an input, connected to the output of the pulse shaper, the second line of the microcontroller port port as an ADC input, it is connected to the output of the first-order aperiodic link, and seventeen microcontroller port lines configured as an output are connected to a nine-digit seven-segment sign indicator.

Due to the inclusion in the utility model of a modern eight-bit Atmel microcontroller of the ATmega8L series with a ten-bit ADC, FLASH program memory, EEPROM and SRAM data memory, which has 28 pins and exceptions from the prototype node for detecting voltage extremes and the ATmega8515L microcontroller that does not have an ADC and having 40 conclusions, the opportunity is provided:

- reducing the systematic error of measuring and calculating the parameters of the electric drive T _ED≃ and α _≃ from 0.39% in the prototype to 0.098% ≈0.1% in the utility model due to the ten-bit structure of the ADC;

- reducing the cost and complexity of the utility model compared to the prototype due to the use of a microcontroller with 28 leads instead of 40 leads and elimination of the voltage extreme detection unit (operational amplifier and other radio elements) from the prototype.

Figure 1 shows a block diagram of a built-in controller of the parameters of the electric drive, and figure 2 is a timing diagram of the built-in controller of parameters of the electric drive.

The built-in controller of the parameters of the electric drive contains (FIG. 1): an electric motor of direct or alternating current 1, which is connected to the load 3 through a controlled mechanical transmission 2; a control sensor 4 is sequentially included in the armature winding of the DC motor 1 or in the stator winding of the AC motor 1; the resistance is two to three orders of magnitude less than the complex resistance of the armature winding or stator winding, which eliminates the influence of the control sensor 4 on the motor 1 ; the control sensor 4 is connected to the input of the peak amplitude detector 5, assembled according to a typical circuit; the output of the peak amplitude detector 5 is connected to the input of the pulse shaper 6, consisting of a differentiating circuit and an amplifier-limiter, and to the input of the aperiodic link of the first order 7; the pulse shaper 6 is connected to the first line of the port of the microcontroller 8 configured as an input, and the aperiodic link of the first order 7 is connected to the second line of the port of the microcontroller 8 configured as an ADC input; Atmel microcontroller 8 of the ATmega8L series operates according to a predetermined algorithm and is connected to a seventeen-digit seven-segment sign indicator 9 of the ALS356A series, using seventeen port lines, which displays the numerical values of the electromechanical time constant of a direct or alternating current electric motor 1 with an accuracy of one millisecond and the dead motion of the mechanical transmission 2 of the electric drive to the nearest thousandth of a degree.

The built-in controller of the parameters of the electric drive (figure 1) works as follows:

1. Before putting the device into operation (see Fig. 1, Fig. 2), the numerical values are entered into the FLASH memory of the programs of the microcontroller 8: Ω _H≃ [r / min] - nominal rotation speed of a direct or alternating current electric motor 1 (taken from technical documentation for the electric motor 1); T _AZ [s] - time constant of the aperiodic link of the first order - a known quantity; k _≃ = U _{1 =} / U _{0 =} = U _1≈ / U _0≈ = U _1≃ / U _0≃ is the multiplicity of the starting voltage (figa, 2b, 2c) on the control sensor 4 and the peak amplitude detector 5. Multiplicity starting voltage k _≃ is a constant value and depending on the type and power of a direct or alternating current electric motor 1 has values k _≃ = ∈ [1, 10] (taken from the technical documentation for electric motor 1). Thus, a FLASH-memory of the microcontroller 8 always recorded programs known numerical values Ω _{H≃, AZ} T, k _≃ and U _0≃. Before turning on the device into operation, the dead-end of mechanical transmission 2 is set to the maximum position (as in the analogue and prototype) and power is supplied to the built-in controller of the electric drive parameters. In addition, if the inclusion in the operation of the device is not the first time, then in the EEPROM-memory of the data of the microcontroller 8 will be recorded T _DE≃ and α _≃ , measured in the last previous cycle of the device.

2. At time t ₁ (see Fig. 1 and Fig. 2), the following processes occur in the built-in controller of electric drive parameters: an AC or DC motor 1 (Fig. 1) starts up and in its stator winding or armature winding an inrush current pulse that generates a voltage pulse u _{4 =} (t ₁ ) = U _{4max =} - for the DC motor (Fig. 2a) and u _4≈ (t ₁ ) = U _4max≈ - for the AC motor ( figb); since the peak amplitude detector 5 is inertialess in the carrier frequency of the supply voltage and inertial in its envelope, the signal at its output will be the same (Fig.2c), both for the AC electric motor (Fig.2b), and for the electric motor direct current (figa) u ₅ (t ₁ ) = U _5max = U _4max≈ = U _{4max =} , which is supplied to the pulse shaper 6 and the first-order aperiodic link 7; the pulse shaper 6 generates a short pulse (Fig.2d) u ₆ (t ₁ ) = U _6max , which starts the microcontroller 8, in which the ADC and the counter of the selection of the dead time of the mechanical transmission T _{MX =} are launched.

3. In the time interval t∈ [t ₁ , t ₂ ] (see figure ₁ and figure 2) in the built-in controller parameters of the electric drive, the following physical processes occur: electric motor 1 starts and continues to rotate; the starting current of the electric motor 1, the voltage at the sensor 4 u _{4 =} (t), u _4≈ (t) and the voltage at the output of the peak amplitude detector 5 u ₅ (t) decrease exponentially (figa, 2b, 2c); the low-speed shaft of the mechanical transmission 2 remains stationary, since the selection of the back stroke occurs, but it has not yet been selected; the voltage at the output of the pulse shaper 6 (Fig.2d) is zero u ₆ (t) = 0, and the voltage at the output of the aperiodic link 7 (Fig.2d) u ₇ (t) increases from zero and tends to its maximum (extreme) value U _≃ ; in the microcontroller 8, a time counter for selecting the dead stroke of the mechanical transmission T _{MXX works} ; The ADC in the microcontroller 8 operates in a cyclic mode and measures the increasing output signal of the aperiodic link 7 (Fig.2d) u ₇ (t∈ [t ₁ , t ₂ ]); it should be noted that the voltage at the output of the aperiodic link 7 in the analytical form has the form

substituting expression (1) - T _ED T in (3), at time t = t ₂ (Fig.2d), a transcendental expression is obtained for the extreme value of the output voltage of the aperiodic link 7

4. At time t ₂ (see Fig. 1 and Fig. 2), the following processes occur in the built-in controller of electric drive parameters: voltage at the sensor 4 u _{4 =} (t), u _4≈ (t) and voltage at the output of peak amplitude detector 5 u ₅ (t) continue to decrease exponentially (figa, 2b, 2c), and the voltage at the output of the pulse shaper 6 remains equal to zero u ₆ (t) = 0 (fig.2g); the voltage at the output of the aperiodic link 7 reaches its extreme value u ₇ (t ₂ ) = U _≃ (Fig. 2e), the ADC of the microcontroller 8 measures the numerical value of U _≃ that is stored in the SRAM-memory of the data of the microcontroller 8, and the ADC stops working.

5. In the time interval t∈ [t ₂ , t ₃ ] (see figure 1 and figure 2) in the built-in controller of the parameters of the electric drive, the following physical processes occur: voltage at the sensor 4 u _{4 =} (t∈ [t ₂ , t ₃ ]), and u _4≈ (t∈ [t ₂ , t ₃ ]) and the voltage at the output of the peak amplitude detector 5 u ₅ (t∈ [t ₂ , t ₃ ]) continue to decrease exponentially (Figs. 2a, 2b, 2c) ;; the low-speed shaft of the mechanical transmission 2 continues to remain motionless, as the selection of the back stroke continues, but it has not yet been selected; the voltage at the output of the shaper 6 is zero u ₆ (t) = 0 (Fig.2g); the microcontroller 8 continues the countdown of the selection of the _deadlock T _MX≃ mechanical transmission 2.

6. At time t ₃ (see FIG. 1 and FIG. 2), the following processes occur in the built-in controller of electric drive parameters: the selection of the dead-end of mechanical transmission 2 is completed, the low-speed shaft of mechanical transmission 2 and load 3 come into rotation; the load on the motor 1 increases stepwise and a second voltage pulse is generated at the sensor 4, and at the output of the peak amplitude detector 5, the pulse u ₅ (t ₃ ) = U _5max = U _4max≈ = U _{4max =} (see Fig. 2a, 2b, 2c ) entering the pulse shaper 6; the pulse shaper 6 generates (Fig. 2d) a second short pulse u ₆ (t ₃ ) = U _6max , which arrives at the microcontroller 8, which stops the countdown of the dead-time selection Т _МХ≃ = t ₃ -t ₁ and remembers its numerical value in its SRAM data memory Thus, at this moment in time, in the SRAM-memory of the data of the microcontroller 8, the numerical values of U _E≃ and T _MX≃ = t ₃ -t ₁ are recorded.

7. In the time interval at t> t ₃ (see Fig. 1 and Fig. 2), the microcontroller 8, according to its operating algorithm, performs calculations according to two expressions (4) and (2), which, for the convenience of presenting the essence

where in the considered time interval:

- known and recorded in the FLASH-memory of the programs of microcontroller 8:

Ω _Н≃ - rated rotation speed of a direct or alternating current electric motor 1;

T _AZ - time constant of the aperiodic link of the first order 7;

k _≃ = U _1≃ / U _0≃ is the multiplicity of the starting voltage at the control sensor 4 of the electric drive of direct or alternating current,

- measured and recorded in the SRAM-memory data of the microcontroller 8:

T _MX≃ - the time of selection of the _deadlock α _≃ mechanical transmission 2 electric drives of direct or alternating current;

U _Э≃ is the numerical value of the extreme voltage of the output signal of the aperiodic link 7 in an electric drive of direct or alternating current,

- unknown and are the sought quantities in the expressions (4) and (2):

T _ED≃ - electromechanical time constant of an electric motor of direct or alternating current in the transcendental equation (4),

α _≃ is the dead stroke of the mechanical transmission of an electric drive of direct or alternating current in the expression (2).

The algorithm of the microcontroller 8 is reduced to the sequential solution of equations (4) and (2):

1. In equation (4), in addition to the desired parameter T _ED≃ , all other parameters are known, but (4) with respect to T _ED≃ is a transcendental equation. In the operation algorithm of microcontroller 8, equation (4) is solved numerically using the optimization of the solution steps by the half-partitioning method. To obtain T _{ED≃ by a} numerical method with an accuracy of a thousandth of a second, 10-12 steps of half splitting are necessary. As a result, the obtained numerical value of the electromechanical time constant of the electric motor 1 of direct or alternating current T _{ED Э} remains in the SRAM data memory, is recorded in the EEPROM data memory of the microcontroller 8, and is displayed in the four high bits of the nine-digit sign indicator 9. with an accuracy of one millisecond.

2. Equation (2) with respect to the desired parameter α _{≃ is} easily solved in an analytical form. In the algorithm of operation of microcontroller 8, the known numerical values of parameters are substituted into the right side of expression (2): Ω _Н≃ - from the FLASH-memory of the programs, and Т _ЭД≃ and Т _MX≃ - from the SRAM-memory of the data of the microcontroller 8. As a result, the obtained numerical value the dead-end of a mechanical transmission 2 of an electric drive of direct or alternating current α _{≃ is} written to the SRAM data memory, it is written to the EEPROM data memory of the microcontroller 8 and displayed in the four least significant bits of the nine-digit sign indicator 9 up to a thousandth of a gram Dusa.

Due to the exclusion from the prototype of the node for detecting the voltage extreme and the ATmega8515L microcontroller that does not have an ADC and has 40 pins and includes in the utility model (Fig. 1) a modern eight-bit Atmel microcontroller of the ATmega8L series with a ten-bit ADC, program memory FLASH-memory - 8 Kbytes , EEPROM-data memory - 512 bytes, SRAM-data memory - 1024 bytes (2 times more than in the prototype), which has 28 pins, it is possible to:

- reducing the systematic error of measuring and calculating the parameters of the electric drive T _ED≃ and α _≃ from 0.39%, typical for the eight-bit representation of information in the prototype, to 0.098% ≈0.1% (i.e., a decrease of almost 4 times) - Utility model through the use of an ATmega8L microcontroller with a ten-bit ADC structure;

- reducing the complexity and, consequently, the cost of a utility model by 10-15% compared to the prototype due to the use of a microcontroller with 28 leads instead of 40 conclusions (with expanded functionality, the utility model microcontroller is 15-20% cheaper than the prototype microcontroller) and exclusions from the circuit a prototype node for detecting an extreme voltage, consisting of an operational amplifier and other radioelements.

Claims (1)

An integrated parameter controller of an electric drive containing an AC or DC motor connected to the load through a controlled mechanical transmission, a control sensor integrated in the motor, a peak amplitude detector, the input of which is connected to the control sensor, a pulse shaper, the input of which is connected to the output of the peak amplitude detector, aperiodic link of the first order, the input of which is connected to the output of the peak amplitude detector, a nine-digit seven-segment sign ALS356A indicator, characterized in that an eight-bit ATmega8L microcontroller with a ten-bit ADC, program FLASH memory, EEPROM and SRAM data memory, the first line of the microcontroller port configured as input, connected to the output of the pulse former, the second line of the microcontroller port, configured as an ADC input, it is connected to the output of the first-order aperiodic link, and seventeen microcontroller port lines configured as output are connected to a nine-digit seven-segment sign indicator.