阅读说明：本技术 电铲变频调速方法、存储介质及系统 (Frequency conversion speed regulation method, storage medium and system for electric shovel ) 是由 张巴图 徐志平 郭俊义 宫福敏 李白羽 于 2020-12-04 设计创作，主要内容包括：本发明提供一种电铲变频调速方法、存储介质及系统,其中的方法包括：根据电铲电机的速度环的饱和状态设置电流饱和标志符；获取所述电流饱和标识符,根据速度环目标转速值和速度环实际转速值以及设定调节参数得到速度环转速给定值；根据所述速度环转速给定值和所述速度环实际转速值得到速度环转速输出量；根据所述速度环转速输出量调整所述电铲电机的速度环转速。通过上述方案能够克服现有技术中变频调速系统速度环适应性差、速度超调量较大的缺点。(The invention provides a frequency conversion speed regulation method, a storage medium and a system of an electric shovel, wherein the method comprises the following steps: setting a current saturation identifier according to the saturation state of a speed loop of the electric shovel motor; acquiring the current saturation identifier, and acquiring a given speed value of the speed ring according to the target speed value and the actual speed value of the speed ring and set adjustment parameters; obtaining a speed ring rotating speed output quantity according to the given speed ring rotating speed value and the actual speed ring rotating speed value; and adjusting the speed ring rotating speed of the electric shovel motor according to the speed ring rotating speed output quantity. The technical scheme can overcome the defects of poor adaptability of a speed ring and large speed overshoot of the variable frequency speed control system in the prior art.)

1. A frequency conversion speed regulation method of an electric shovel is characterized by comprising the following steps:

setting a current saturation identifier according to the saturation state of a speed loop of the electric shovel motor;

acquiring the current saturation identifier, and acquiring a given speed value of the speed ring according to the target speed value and the actual speed value of the speed ring and set adjustment parameters;

obtaining a speed ring rotating speed output quantity according to the given speed ring rotating speed value and the actual speed ring rotating speed value;

and adjusting the speed ring rotating speed of the electric shovel motor according to the speed ring rotating speed output quantity.

2. The frequency-conversion speed-regulating method of the electric shovel according to claim 1, wherein in the step of obtaining the current saturation identifier and obtaining the given value of the rotating speed of the speed ring according to the target rotating speed value of the speed ring, the actual rotating speed value of the speed ring and the set regulating parameter:

and if the current saturation identifier indicates that the saturation state of the speed ring is an unsaturated state, obtaining the given value of the rotating speed of the speed ring by a step function method.

3. The frequency-conversion speed-regulating method of the electric shovel according to claim 2, wherein in the step of obtaining the current saturation identifier and obtaining the given value of the rotating speed of the speed ring according to the target rotating speed value of the speed ring, the actual rotating speed value of the speed ring and the set regulating parameters:

and if the current saturation identifier indicates that the saturation state of the speed ring is a saturated state, taking the actual rotating speed value of the speed ring as the given rotating speed value of the speed ring.

4. The frequency-conversion speed-regulating method of the electric shovel according to any one of claims 1 to 3, wherein the step of obtaining the output quantity of the speed ring rotating speed according to the given value of the speed ring rotating speed and the actual value of the speed ring rotating speed comprises the following steps:

obtaining a speed difference percentage according to the given speed value of the speed ring and the actual speed value of the speed ring;

obtaining a proportional term and an integral term in the speed ring according to the speed difference percentage;

and taking the sum of the proportional term and the integral term as the speed ring rotating speed output quantity.

5. The method for variable frequency speed regulation of an electric shovel according to claim 4, wherein in the step of obtaining the proportional term and the integral term in the speed ring according to the percentage of the speed difference:

said proportional term is given byObtained in the following way: k_P＝K_P*×y；

The integral term is obtained by: k_I＝∑K_i*×y；

Wherein y is obtained by: omega_err％＝ay²+by+c，y≥0,ω_err% is the speed difference percentage;

in the above, a, b, c are empirical coefficients, K_PIs the velocity loop iteration scaling factor, K_IVelocity loop iterates the integral coefficient.

6. The frequency conversion speed regulation method of an electric shovel according to claim 5, further comprising the steps of:

if the rotating speed output quantity of the speed ring is larger than the current amplitude limiting value of the motor speed ring, the integral quantity is adjusted in the following way: k_I＝K_I-Kp × y until said speed loop rotational speed output equals a current limit value of the motor speed loop;

if the rotating speed output quantity of the speed ring is smaller than the current amplitude limiting value of the motor speed ring, the integral quantity is adjusted in the following mode: k_I＝-K_I-Kp x y until said speed loop rotational speed output equals the current limit value of the motor speed loop.

7. The frequency-conversion speed-regulating method of the electric shovel according to claim 6, wherein in the step of obtaining the percentage of the speed difference value according to the given value of the speed ring and the actual speed ring:

when the set position on the speed ring reaches the position of the detection point, the set position is used as the operation time, and the set value omega of the rotating speed of the speed ring at the operation time is used as the set value omega_rSum of actual speed values ω of the speed rings_rObtaining the speed difference percentage: eta% ═ omega_r*/ω_r。

8. The frequency-conversion speed-regulating method of the electric shovel according to claim 7, wherein in the step of obtaining the current saturation identifier and obtaining the given value of the rotating speed of the speed ring according to the target rotating speed value of the speed ring, the actual rotating speed value of the speed ring and the set regulating parameters:

and the actual rotating speed value of the speed ring is detected by a photoelectric encoder arranged on the rotating shaft of the motor.

9. A storage medium, wherein the storage medium stores program information, and a computer reads the program information and executes the method according to any one of claims 1 to 8.

10. A variable-frequency speed regulation system of an electric shovel, which is characterized by comprising at least one processor and at least one memory, wherein program information is stored in at least one memory, and after the program information is read by at least one processor, the variable-frequency speed regulation system of the electric shovel executes the variable-frequency speed regulation method of any one of claims 1 to 8.

Technical Field

The invention relates to the technical field of mining electric transmission, in particular to a frequency conversion speed regulation method, a storage medium and a system of an electric shovel.

Background

Based on production needs, the mine electric shovel puts forward high requirements on a variable-frequency speed regulation control method and universality of a power module in an electric transmission system of a hoisting motor, so that a core control method, namely a double closed-loop control method, of the electric system of the hoisting motor is required to be started quickly, reach a target stroke in a short time, improve the working efficiency and bring forward new requirements on the aspect of convenience for modular control. On the basis, a variable frequency speed regulation control method is provided.

The variable frequency speed control method is based on space vectors, wherein a speed loop is an outer loop, a current loop is an inner loop, and the method is always used as a mainstream method for controlling a motor. However, the above control method generally has the following problems: when the rotating speed of the motor rises to a given value in the starting process of the electric shovel, the input deviation of the rotating speed regulator is reduced to zero, but the integral action is continuously increased to cause the motor to be accelerated, so that the rotating speed of the motor is over-regulated, and if the speed ring is simply added with an amplitude limit to avoid the situation that the given value of the current is too large, a nonlinear link is generated in a system, and the system can stall and fail if the nonlinear link is serious.

Therefore, there is a need for a variable frequency speed regulation scheme for an electric shovel that avoids the above problems.

Disclosure of Invention

The invention aims to provide a frequency conversion speed regulation method, a storage medium and a system of an electric shovel, and aims to solve the technical problem of poor reliability caused by motor overshoot in the speed regulation process of the electric shovel in the prior art.

Therefore, some embodiments of the invention provide a frequency conversion speed regulation method for an electric shovel, which comprises the following steps:

setting a current saturation identifier according to the saturation state of a speed loop of the electric shovel motor;

acquiring the current saturation identifier, and acquiring a given speed value of the speed ring according to the target speed value and the actual speed value of the speed ring and set adjustment parameters;

obtaining a speed ring rotating speed output quantity according to the given speed ring rotating speed value and the actual speed ring rotating speed value;

and adjusting the speed ring rotating speed of the electric shovel motor according to the speed ring rotating speed output quantity.

Optionally, in the method for variable-frequency speed regulation of an electric shovel, the current saturation identifier is obtained, and the given value of the rotating speed of the speed ring is obtained according to the target rotating speed value of the speed ring, the actual rotating speed value of the speed ring and the set regulation parameter:

and if the current saturation identifier indicates that the saturation state of the speed ring is an unsaturated state, obtaining the given value of the rotating speed of the speed ring by a step function method.

Optionally, in the method for variable-frequency speed regulation of an electric shovel, the current saturation identifier is obtained, and the given value of the rotating speed of the speed ring is obtained according to the target rotating speed value of the speed ring, the actual rotating speed value of the speed ring and the set regulation parameter:

and if the current saturation identifier indicates that the saturation state of the speed ring is a saturated state, taking the actual rotating speed value of the speed ring as the given rotating speed value of the speed ring.

Optionally, in the method for variable-frequency speed regulation of an electric shovel, the step of obtaining the output quantity of the speed loop according to the given value of the speed loop and the actual value of the speed loop comprises:

obtaining a speed difference percentage according to the given speed value of the speed ring and the actual speed value of the speed ring;

obtaining a proportional term and an integral term in the speed ring according to the speed difference percentage;

and taking the sum of the proportional term and the integral term as the speed ring rotating speed output quantity.

Optionally, in the method for variable-frequency speed regulation of an electric shovel, the step of obtaining the proportional term and the integral term in the speed loop according to the percentage of the speed difference is as follows:

the proportion term is obtained by the following method: k_P＝K_P*×y；

The integral term is obtained by: k_I＝∑K_i*×y；

Wherein y is obtained by: omega_err％＝ay²+by+c，y≥0,ω_err% is the speed difference percentage;

in the above, a, b, c are empirical coefficients, K_PIs the velocity loop iteration scaling factor, K_IVelocity loop iterates the integral coefficient.

Optionally, the above method for variable-frequency speed regulation of an electric shovel further includes the following steps:

if the rotating speed output quantity of the speed ring is larger than the current amplitude limiting value of the motor speed ring, the integral quantity is adjusted in the following way: k_I＝K_I-Kp × y until said speed loop rotational speed output equals a current limit value of the motor speed loop;

if the rotating speed output quantity of the speed ring is smaller than the current amplitude limiting value of the motor speed ring, the integral quantity is adjusted in the following mode: k_I＝-K_I-Kp x y until said speed loop rotational speed output equals the current limit value of the motor speed loop.

Optionally, in the method for variable-frequency speed regulation of an electric shovel, a speed difference percentage is obtained according to the given speed value of the speed ring and the actual speed value of the speed ring:

when the set position on the speed ring reaches the position of the detection point, the set position is used as the operation time, and the set value omega of the rotating speed of the speed ring at the operation time is used as the set value omega_rSum of actual speed values ω of the speed rings_rObtaining the speed difference percentage: eta% ═ omega_r*/ω_r。

Optionally, in the method for variable-frequency speed regulation of an electric shovel, the current saturation identifier is obtained, and the given value of the rotating speed of the speed ring is obtained according to the target rotating speed value of the speed ring, the actual rotating speed value of the speed ring and the set regulation parameter:

and the actual rotating speed value of the speed ring is detected by a photoelectric encoder arranged on the rotating shaft of the motor.

Some embodiments of the present invention further provide a storage medium, where the storage medium stores program information, and a computer reads the program information and then executes the method for frequency conversion and speed regulation of an electric shovel according to any one of the above descriptions.

The invention also provides a variable-frequency speed regulating system of the electric shovel, which comprises at least one processor and at least one memory, wherein program information is stored in at least one memory, and the at least one processor reads the program information and then executes the variable-frequency speed regulating method of the electric shovel.

Compared with the prior art, the technical scheme provided by the invention at least has the following beneficial effects: whether the speed ring is saturated or not is judged by obtaining the current saturation identifier, then a given value is obtained according to the target speed value and the actual rotating speed value, and the output quantity of the speed ring can be determined according to the given value and the actual rotating speed value so as to adjust the rotating speed of the speed ring of the electric shovel motor. The technical scheme can overcome the defects of poor adaptability of a speed ring and large speed overshoot of the variable frequency speed control system in the prior art.

Drawings

FIG. 1 is a flow chart of a method for frequency conversion and speed regulation of an electric shovel according to an embodiment of the present invention;

FIG. 2 is a flow chart of a variable frequency speed control method of an electric shovel according to another embodiment of the present invention;

FIG. 3 is a block diagram of a control system of the variable frequency speed control system applied to the variable frequency speed control method of the electric shovel shown in FIG. 1 or FIG. 2;

fig. 4 is a schematic diagram of a hardware connection structure of a variable-frequency speed control system of an electric shovel according to another embodiment of the present invention.

Detailed Description

The embodiments of the present invention will be further described with reference to the accompanying drawings. In the description of the present invention, it should be noted that the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", etc., indicate orientations or positional relationships based on the orientations or positional relationships shown in the drawings, and are only for convenience of description of the present invention, and do not indicate or imply that the device or assembly referred to must have a specific orientation, be constructed and operated in a specific orientation, and thus, should not be construed as limiting the present invention. Furthermore, the terms "first," "second," and "third" are used for descriptive purposes only and are not to be construed as indicating or implying relative importance. Wherein the terms "first position" and "second position" are two different positions.

Some embodiments of the present application provide a method for variable frequency speed regulation of an electric shovel, which may be applied to an electric shovel controller, as shown in fig. 1, where the method may include the following steps:

s101: a current saturation flag is set based on a saturation state of a speed loop of the shovel motor. The FLAG may be set as a current saturation FLAG, and when FLAG equals false and indicates that the speed ring is in an unsaturated state, FLAG equals true and indicates that the speed ring is in a saturated state, the FLAG may be changed according to an actual state of the speed ring, otherwise, FLAG indicates an abnormal state, that is, an overshoot state, and at this time, the rotation speed of the speed ring of the motor should be rapidly reduced.

S102: and acquiring the current saturation identifier, and acquiring a given speed value of the speed ring according to the target speed value of the speed ring, the actual speed value of the speed ring and the set adjusting parameter. The actual rotating speed value of the speed ring can be obtained by monitoring according to a monitoring part arranged in the motor, the adjusting parameter is set to be standard data which is known in advance and stored well, and the target rotating speed value of the speed ring is an ideal rotating speed value in the current processing period.

S103: and obtaining the output quantity of the rotating speed of the speed ring according to the given value of the rotating speed of the speed ring and the actual rotating speed value of the speed ring.

S104: and adjusting the speed ring rotating speed of the electric shovel motor according to the speed ring rotating speed output quantity. The method aims to ensure that the rotating speed value of the speed ring of the electric shovel motor meets the target rotating speed value and the current saturation identifier is not abnormal.

According to the scheme, whether the speed ring is saturated or not is judged by obtaining the current saturation identifier, then the given value is obtained according to the target speed value and the actual rotating speed value, and the output quantity of the speed ring can be determined according to the given value and the actual rotating speed value so as to adjust the rotating speed of the speed ring of the electric shovel motor. The technical scheme can overcome the defects of poor adaptability of a speed ring and large speed overshoot of the variable frequency speed control system in the prior art.

Further, in step S102, if the current saturation flag indicates that the saturation state of the speed loop is an unsaturated state, the given value of the rotation speed of the speed loop is obtained by a step function method. And if the current saturation identifier indicates that the saturation state of the speed ring is a saturated state, taking the actual rotating speed value of the speed ring as the given rotating speed value of the speed ring. Therefore, the actual rotating speed value of the motor speed ring can be ensured to reach the maximum value in the ideal state, the overshoot condition cannot occur, and the power utilization efficiency of the electric shovel is improved.

Preferably, referring to fig. 2, the method for variable-frequency speed regulation of an electric shovel may include:

s201: reading a target speed value omega of a speed ring_refActual rotation speed value omega of speed ring_rA current saturation FLAG; the actual rotation speed value omega of the speed ring_rThe motor rotating speed actually detected by the photoelectric encoder is obtained.

S202: according to the current saturation identifier FLAG and the target rotating speed value omega of the speed ring_refSetting regulation parameters (which can be phase function variable setting values), and calculating a given speed value omega of the speed ring_rA first step of; wherein: when FLAG is false, the current loop is not saturated, and the given value omega of the rotating speed of the speed loop is_rOutput by a step function, ω_r*＝ω_ref+ STEP, where STEP is the speed STEP; when FLAG is true, the speed ring rotating speed set value omega_rActual speed value omega of speed ring_r；

Step S203: given value omega according to rotating speed of speed ring_rAnd actual rotation speed value omega of speed ring_rCalculating the velocity difference ω_errPercentage of difference in sum velocity ω_errPercent; in this step, the position signal s is detected according to the limit encoder_refWhen true, ω_r*＝ω_rX η%, η% is the percentage of the current speed.

Step S204: according to the difference value omega_errDifference in velocity in percentRatio omega_errPercent, calculating the output quantity i of the rotating speed of the speed ring_q1ref(ii) a Wherein, the percentage omega is determined according to the speed difference_err% gives a proportional term and an integral term, where the proportional term K_P＝K_P*×y，ω_err％＝ay²+ by + c (y is more than or equal to 0), integral term K_I＝∑K_i*×y，ω_err％＝ay²+ by + c (y is not less than 0), wherein K_PIs the velocity loop iteration scaling factor, K_IThe sum of the proportional term and the integral term is i_q1ref。

The step S205: according to the rotating speed output quantity i of the speed ring_q1refJudging whether the current is larger than the current limiting value I_q1mIs there a If the speed ring rotates at the output quantity i_q1ref＞I_q1mThen, step S209 is executed; otherwise, executing step S206;

s206: according to the rotating speed output quantity i of the speed ring_q1refJudging whether the current is smaller than the current limiting value I_q1mIs there a If yes, executing step S207, otherwise executing step S208;

s207: a saturation FLAG is set to indicate that the speed loop is in an unsaturated state.

S208: adjusting the integral quantity K_I＝-i_q1ref-Kp×y,i_q1ref＝I_q1m(ii) a Limiting the speed output of the speed loop to I_q1mAnd sets a saturation FLAG true indicating whether the current speed loop is in a saturated state.

S209: adjusting the integral quantity K_I＝i_q1ref-Kp×y，i_q1ref＝I_q1mLimiting the output of speed loop to I_q1mAnd sets a saturation FLAG true indicating whether the current speed loop is in a saturated state.

In the scheme, in the transition process of starting and braking of the motor, for stable starting and braking and small mechanical impact, a torque control mode with a speed amplitude limit is adopted for rotation control, namely, the main command is given by torque, and the given size determines the size of the output torque of the motor and the starting and braking speed during starting and braking. In addition, two inverters drive two variable frequency motors for an electric shovel slewing mechanism, the two motors are coupled through gears, the load characteristic of the slewing mechanism belongs to large-inertia rotating load, under the normal operation condition, one working cycle only carries out positive and negative rotating motion of 0-90 degrees and 90-0 degrees, the motion period is basically in the transition process of starting and braking, and because the two motors have different gear coupling gaps, the service life of the motor is long, the loss difference is large, the model parameters are different, and unstable starting and braking and large mechanical impact are easy to occur during starting and braking. The invention proposes a scheme: a torque master-slave control technology is adopted between two inverters, namely: one inverter is used as a main device and adopts a closed-loop torque control mode; the other inverter is a slave device, and adopts a speed control mode, and the given speed value of the other inverter is directly from the master device. Therefore, the speed of the two motors of the slewing mechanism is controllable, and the output force coordination of the two motors is ensured, so that the mechanical impact is reduced, the abrasion of the slewing gear is reduced, and the running coordination of the two slewing motors is optimal. In the above scheme, aiming at the execution mode in the speed control mode, the given value of the motor speed is adjusted, the speed is given to the step curve, the robustness of the system is effectively improved, the system is better adapted to load disturbance, and overshoot of the speed in the acceleration and deceleration process is avoided.

Some embodiments of the present invention provide a storage medium, where the storage medium stores program information, and a computer reads the program information and executes the method for frequency conversion and speed regulation of an electric shovel according to any one of the above method embodiments.

As shown in fig. 3, the control system applied in the variable frequency speed control method of the electric shovel is a typical closed-loop vector control system (space vector control of a speed encoder and a position encoder), and the control object is a motor, such as an asynchronous motor. Compared with the existing closed-loop space vector control system, the system in fig. 3 adds a step function output device, which is equivalent to adopting a parabolic speed regulator to replace the traditional PI speed regulator, and the arrangement of other components can refer to the existing closed-loop vector control system. The current loop control part, such as excitation current regulation, torque current regulation, Park inverse transformation, dead zone compensation, torque current, excitation current separation, etc., is the same as the prior art, so details are not described in the embodiments of the present application, and only the speed loop control part is described in detail.

Some embodiments of the present invention further provide an electric shovel variable frequency speed control system, as shown in fig. 4, including at least one processor 11 and at least one memory 12, where at least one of the memories 12 stores program instructions, and after the at least one processor 11 executes the program instructions, it executes any one of the electric shovel variable frequency speed control methods applied in the control end. The system may further comprise: an input device 13 and an output device 14. The processor 11, memory 12, input device 13 and output device 14 may be communicatively connected. Memory 12, which is a non-volatile computer-readable storage medium, may be used to store non-volatile software programs, non-volatile computer-executable programs, and modules. The processor 11 executes various functional applications and data processing by running nonvolatile software programs, instructions and modules stored in the memory 12, so as to realize the electric shovel frequency conversion speed regulation method.

Finally, it should be noted that: the above examples are only intended to illustrate the technical solution of the present invention, but not to limit it; although the present invention has been described in detail with reference to the foregoing embodiments, it will be understood by those of ordinary skill in the art that: the technical solutions described in the foregoing embodiments may still be modified, or some technical features may be equivalently replaced; and the modifications or the substitutions do not make the essence of the corresponding technical solutions depart from the scope of the technical solutions of the embodiments of the present invention.