阅读说明：本技术 基于双馈电机的起重机货物平滑提升控制系统及方法 (Crane cargo smooth lifting control system and method based on double-fed motor ) 是由 王保杰 李民恩 于 2020-08-28 设计创作，主要内容包括：本发明公开了一种基于双馈电机的起重机货物平滑提升控制系统及方法。基于双馈电机的起重机货物平滑提升控制系统,包括双馈电机M,及与所述双馈电机M电性连接的启动单元、转子电流控制单元、保护单元和控制电路；所述启动单元包括第一接触器KM1和启动限流电阻FR；所述转子电流控制单元包括第二接触器KM2、不可控整流器DR、电感Ls、功率开关管S、二极管D、储能电容C、逆变桥B和缓冲电感LD；所述保护单元包括第三接触器KM3和变压器T。本发明还公开了一种基于双馈电机的起重机货物平滑提升控制方法。(The invention discloses a crane cargo smooth lifting control system and method based on a double-fed motor. The crane cargo smooth lifting control system based on the double-fed motor comprises the double-fed motor M, and a starting unit, a rotor current control unit, a protection unit and a control circuit which are electrically connected with the double-fed motor M; the starting unit comprises a first contactor KM1 and a starting current limiting resistor FR; the rotor current control unit comprises a second contactor KM2, an uncontrollable rectifier DR, an inductor Ls, a power switch tube S, a diode D, an energy storage capacitor C, an inverter bridge B and a buffer inductor LD; the protection unit includes a third contactor KM3 and a transformer T. The invention also discloses a crane cargo smooth lifting control method based on the double-fed motor.)

1. A crane cargo smooth lifting control system based on a double-fed motor is characterized by comprising a double-fed motor M, a starting unit, a rotor current control unit, a protection unit and a control circuit, wherein the starting unit, the rotor current control unit, the protection unit and the control circuit are electrically connected with the double-fed motor M;

the starting unit comprises a first contactor KM1 and a starting current limiting resistor FR;

the stator coil of the doubly-fed motor M is connected with a three-phase power grid, the rotor coil of the doubly-fed motor M is connected with the first contactor KM1, the first contactor KM1 is connected with one end of the starting current limiting resistor FR, and the other end of the starting current limiting resistor FR is grounded;

the rotor current control unit comprises a second contactor KM2, an uncontrollable rectifier DR, an inductor Ls, a power switch tube S, a diode D, an energy storage capacitor C, an inverter bridge B and a buffer inductor LD;

one end of the second contactor KM2 is connected with the rotor coil of the doubly-fed motor M, the other end of the second contactor KM2 is connected with the input end of the uncontrollable rectifier DR, the high voltage side of the output end of the uncontrollable rectifier DR is connected with the inductor Ls, the inductor Ls is connected with the source electrode of the power switch tube S, the inductor Ls is connected with the cathode of the diode D, the anode of the diode D is connected with the anode of the energy storage capacitor C and the high-voltage side of the input end of the inverter bridge B, the low-voltage side of the input end of the inverter bridge B is connected with one end of the buffer inductor LD, the low-voltage side of the uncontrollable rectifier DR is connected with the drain electrode of the power switch tube S, the low-voltage side of the energy storage capacitor C is connected with the low-voltage side of the uncontrollable rectifier DR, and the low-voltage side of the uncontrollable rectifier DR is connected with the other end of the buffer inductor LD;

the protection unit comprises a third contactor KM3 and a transformer T;

one end of the third contactor KM3 is connected with the output end of the inverter bridge B, the other end of the third contactor KM3 is connected with the low-voltage side of the transformer T, and the high-voltage side of the transformer T is connected with a three-phase power grid.

2. A method for controlling smooth lifting of crane cargos based on a doubly-fed motor is characterized by comprising the following steps:

the control circuit sends out an instruction to control the double-fed motor M to enter a starting state;

an inverter bridge B in the rotor current control unit works at a fixed duty ratio, and the current i 'fed into an alternating current bus by the doubly-fed motor M is controlled by controlling the on-off of a power switch tube S'_f；

Regulating the current i 'fed to the AC busbar'_fTo control the electromagnetic torque of the doubly-fed machine M;

the control circuit controls the double-fed motor M in a time-sharing mode so as to achieve smooth lifting of goods.

3. The method for controlling smooth lifting of the goods by the crane based on the doubly-fed motor of claim 2, wherein the controlling circuit sends out a command to control the doubly-fed motor M to enter a starting state, and the method comprises the following steps: the control circuit sends out instructions to close the first contactor KM1, open the second contactor KM2 and open the third contactor KM3, so that the double-fed motor M enters a starting state.

4. The method for controlling smooth lifting of the goods in the crane based on the doubly-fed motor of claim 3, wherein the control circuit performs time-phased control on the doubly-fed motor M, and the method comprises the following steps: when the rotating speed of the doubly-fed motor M reaches a set value, the control circuit controls the second contactor KM2 to be closed and the third contactor KM3 to be closed, and controls the duty ratio of a power switch tube S driving signal PMW1 in the rotor current control unit to enable current i 'fed into the alternating current bus to be fed'_fAt a constant value to maintain the speed of the doubly fed machine constant.

5. The double-fed motor based crane cargo smooth lifting device according to claim 4The lift control method is characterized in that the control circuit performs time-division control on the doubly-fed motor M, and comprises the following steps: when detecting the current i 'fed to the AC bus'_fAnd during sudden increase, the first contactor KM1 is switched off, and the current i' f fed into the alternating current bus is reduced by changing the duty ratio of a power switch tube S driving signal PMW1, so that the electromagnetic torque of the double-fed motor M is rapidly increased.

6. The method for controlling smooth lifting of the goods in the crane based on the doubly-fed motor of claim 5, wherein the control circuit performs time-phased control on the doubly-fed motor M, and the method comprises the following steps: when the rotating speed of the doubly-fed motor M is detected to suddenly increase, the duty ratio of a driving signal PMW1 of a power switch tube S is changed, so that the current i' f fed into an alternating current bus is reduced, and the goods rise in a uniform acceleration motion.

7. The method for controlling smooth lifting of the goods in the crane based on the doubly-fed motor of claim 6, wherein the control circuit performs time-phased control on the doubly-fed motor M, and the method comprises the following steps: when the rotating speed of the double-fed motor M reaches the rated rotating speed, the power switch tube S is controlled to be in a conducting state, so that the double-fed motor M operates at the rated rotating speed, and the goods are lifted at the maximum speed at a constant speed.

Technical Field

The invention relates to the technical field of crane cargo lifting, in particular to a system and a method for controlling smooth lifting of crane cargo based on a double-fed motor.

Background

The smooth lifting of the goods of the crane is one of the most important parameters of the crane parameters, and the smooth starting of the goods of the crane can greatly reduce the damage rate of the goods and prolong the service life of a motor and a fishing rope in the crane. The speed of the lifting speed of the crane directly influences the progress of the whole project, and how to smoothly and quickly improve the lifting speed becomes a topic discussed by various crane manufacturers and also becomes a competitive condition of the crane industry in terms of performance.

At present, a winding motor is mostly used in a crane, and a frequency converter is used as a rotating speed adjusting device. The frequency converter has the characteristics of wide speed regulation range and capability of operating below 20% of the rated rotating speed, so that the speed can be increased by increasing the frequency of the output voltage of the frequency converter to increase the rotating speed of the motor. As is well known, the frequency converter is particularly suitable for constant torque load, but the load of the whole lifting process is always in dynamic change due to the stress of a fishing rope in the lifting process of the goods, which means that the frequency converter is difficult to exert the maximum performance in the starting process and only can realize the lifting of light-load goods.

Doubly-fed machines have been applied to the field of cranes step by step due to their excellent performance. The chopper type rotor variable frequency speed regulation scheme is simple to realize and reliable in work, and is widely applied to the field of speed regulation of double-fed motors. Unfortunately, at present, there are few crane cargo smooth lifting control systems and methods based on double-fed motors.

Disclosure of Invention

Based on the above, the invention aims to provide a system and a method for controlling smooth lifting of a crane cargo based on a double-fed motor.

In a first aspect, the crane cargo smooth lifting control system based on the double-fed motor comprises a double-fed motor M, and a starting unit, a rotor current control unit, a protection unit and a control circuit which are electrically connected with the double-fed motor M;

the starting unit comprises a first contactor KM1 and a starting current limiting resistor FR;

the stator coil of the doubly-fed motor M is connected with a three-phase power grid, the rotor coil of the doubly-fed motor M is connected with the first contactor KM1, the first contactor KM1 is connected with one end of the starting current limiting resistor FR, and the other end of the starting current limiting resistor FR is grounded;

the rotor current control unit comprises a second contactor KM2, an uncontrollable rectifier DR, an inductor Ls, a power switch tube S, a diode D, an energy storage capacitor C, an inverter bridge B and a buffer inductor LD;

one end of the second contactor KM2 is connected with the rotor coil of the doubly-fed motor M, the other end of the second contactor KM2 is connected with the input end of the uncontrollable rectifier DR, the high voltage side of the output end of the uncontrollable rectifier DR is connected with the inductor Ls, the inductor Ls is connected with the source electrode of the power switch tube S, the inductor Ls is connected with the cathode of the diode D, the anode of the diode D is connected with the anode of the energy storage capacitor C and the high-voltage side of the input end of the inverter bridge B, the low-voltage side of the input end of the inverter bridge B is connected with one end of the buffer inductor LD, the low-voltage side of the uncontrollable rectifier DR is connected with the drain electrode of the power switch tube S, the low-voltage side of the energy storage capacitor C is connected with the low-voltage side of the uncontrollable rectifier DR, and the low-voltage side of the uncontrollable rectifier DR is connected with the other end of the buffer inductor LD;

the protection unit comprises a third contactor KM3 and a transformer T;

one end of the third contactor KM3 is connected with the output end of the inverter bridge B, the other end of the third contactor KM3 is connected with the low-voltage side of the transformer T, and the high-voltage side of the transformer T is connected with a three-phase power grid.

According to the crane cargo smooth lifting control system based on the double-fed motor, the double-fed motor M, the starting unit, the rotor current control unit, the protection unit and the control circuit are arranged, the starting unit, the rotor current control unit, the protection unit and the control circuit are electrically connected with the double-fed motor M, and the control circuit is used for controlling the action of components in the rotor current control unit, so that the double-fed motor M is controlled in a time-sharing section mode, the cargo smooth lifting of a crane is achieved, and the problems that in the prior art, a frequency converter cannot exert the maximum performance of the frequency converter easily, and only light-load cargo.

In a second aspect, the invention provides a method for controlling smooth lifting of a crane cargo based on a doubly-fed motor, comprising the following steps:

the control circuit sends out an instruction to control the double-fed motor M to enter a starting state;

an inverter bridge B in the rotor current control unit works at a fixed duty ratio, and the current i 'fed into an alternating current bus by the doubly-fed motor M is controlled by controlling the on-off of a power switch tube S'_f；

Regulating the current i 'fed to the AC busbar'_fTo control the electromagnetic torque of the doubly-fed machine M;

the control circuit controls the double-fed motor M in a time-sharing mode so as to achieve smooth lifting of goods.

According to the crane cargo smooth lifting control method based on the doubly-fed motor, the inverter bridge B in the rotor current control unit works at a fixed duty ratio, and the current i 'fed into the alternating current bus by the doubly-fed motor M is controlled by controlling the on-off of the power switch tube S'_fAnd by regulating the current i 'fed to the AC bus'_fThe electromagnetic torque of the double-fed motor M is controlled, the double-fed motor M is controlled in a time-sharing mode through the control circuit, so that the effect of smooth lifting of goods of the crane is achieved, and the problem that in the prior art, a frequency converter cannot exert the maximum performance of the frequency converter and can only achieve lifting of light-load goods is solved.

In an embodiment of the foregoing technical solution, the controlling circuit sends an instruction to control the doubly-fed motor M to enter the starting state, including: the control circuit sends out instructions to close the first contactor KM1, open the second contactor KM2 and open the third contactor KM3, so that the double-fed motor M enters a starting state.

In an embodiment of the foregoing technical solution, the time-division control of the doubly-fed motor M by the control circuit includes: when the rotating speed of the doubly-fed motor M reaches a set value, the control circuit controls the second contactor KM2 to be closed and the third contactor KM3 to be closed, and controls the duty ratio of a power switch tube S driving signal PMW1 in the rotor current control unit to enable current i 'fed into the alternating current bus to be fed'_fAt a constant value to maintain the speed of the doubly fed machine constant.

In an embodiment of the foregoing technical solution, the time-division control of the doubly-fed motor M by the control circuit includes: when detecting the feed-in ACCurrent i 'of bus'_fAnd during sudden increase, the first contactor KM1 is switched off, and the current i' f fed into the alternating current bus is reduced by changing the duty ratio of a power switch tube S driving signal PMW1, so that the electromagnetic torque of the double-fed motor M is rapidly increased.

In an embodiment of the foregoing technical solution, the time-division control of the doubly-fed motor M by the control circuit includes: when the rotating speed of the doubly-fed motor M is detected to suddenly increase, the duty ratio of a driving signal PMW1 of a power switch tube S is changed, so that the current i' f fed into an alternating current bus is reduced, and the goods rise in a uniform acceleration motion.

In an embodiment of the foregoing technical solution, the time-division control of the doubly-fed motor M by the control circuit includes: when the rotating speed of the double-fed motor M reaches the rated rotating speed, the power switch tube S is controlled to be in a conducting state, so that the double-fed motor M operates at the rated rotating speed, and the goods are lifted at the maximum speed at a constant speed.

Compared with the prior art, the crane cargo smooth lifting control system and method based on the double-fed motor control device have the advantages that the double-fed motor M, the starting unit, the rotor current control unit, the protection unit and the control circuit are electrically connected with the double-fed motor M, the inverter bridge B in the rotor current control unit works at a fixed duty ratio, and the on-off of the power switch tube S is controlled to control the current i 'fed into the alternating current bus by the double-fed motor M'_fAnd by regulating the current i 'fed to the AC bus'_fThe electromagnetic torque of the double-fed motor M is controlled, the double-fed motor M is controlled in a time-sharing mode through the control circuit, the effect of smooth lifting of goods of the crane is achieved, the problem that in the prior art, a frequency converter cannot exert the maximum performance of the frequency converter easily, and only light-load goods can be lifted is solved, and the application of a double-fed motor speed regulating system in the field of cranes is facilitated.

For a better understanding and practice, the invention is described in detail below with reference to the accompanying drawings.

Drawings

Fig. 1 is a circuit connection diagram of the cargo smooth lifting control system of the crane based on the double-fed motor.

FIG. 2 isCurrent i 'fed to AC bus'_fSchematic of the change over time.

Detailed Description

The terms of orientation of up, down, left, right, front, back, top, bottom, and the like, referred to or may be referred to in this specification, are defined relative to their configuration, and are relative concepts. Therefore, it may be changed according to different positions and different use states. Therefore, these and other directional terms should not be construed as limiting terms.

The implementations described in the exemplary embodiments below are not intended to represent all implementations consistent with the present disclosure. Rather, they are merely examples of methods consistent with certain aspects of the present disclosure, as detailed in the appended claims.

The terminology used in the present disclosure is for the purpose of describing particular embodiments only and is not intended to be limiting of the disclosure. As used in this disclosure and the appended claims, the singular forms "a," "an," and "the" are intended to include the plural forms as well, unless the context clearly indicates otherwise. It should also be understood that the term "and/or" as used herein refers to and encompasses any and all possible combinations of one or more of the associated listed items.

Referring to fig. 1, fig. 1 is a circuit connection diagram of a cargo smooth lifting control system of a crane based on a doubly-fed motor according to the present invention.

In a first aspect, the crane cargo smooth lifting control system based on the double-fed motor comprises a double-fed motor M, and a starting unit, a rotor current control unit, a protection unit and a control circuit which are electrically connected with the double-fed motor M.

The starting unit comprises a first contactor KM1 and a starting current limiting resistor FR.

The stator coil of the doubly-fed motor M is connected with a three-phase power grid, the rotor coil of the doubly-fed motor M is connected with the first contactor KM1, the first contactor KM1 is connected with one end of the starting current limiting resistor FR, and the other end of the starting current limiting resistor FR is grounded.

The rotor current control unit comprises a second contactor KM2, an uncontrollable rectifier DR, an inductor Ls, a power switch tube S, a diode D, an energy storage capacitor C, an inverter bridge B and a buffer inductor LD.

One end of the second contactor KM2 is connected with the rotor coil of the doubly-fed motor M, the other end of the second contactor KM2 is connected with the input end of the uncontrollable rectifier DR, the high voltage side of the output end of the uncontrollable rectifier DR is connected with the inductor Ls, the inductor Ls is connected with the source electrode of the power switch tube S, the inductor Ls is connected with the cathode of the diode D, the anode of the diode D is connected with the anode of the energy storage capacitor C and the high-voltage side of the input end of the inverter bridge B, the low-voltage side of the input end of the inverter bridge B is connected with one end of the buffer inductor LD, the low-voltage side of the uncontrollable rectifier DR is connected with the drain electrode of the power switch tube S, the low-voltage side of the energy storage capacitor C is connected with the low-voltage side of the uncontrollable rectifier DR, and the low-voltage side of the uncontrollable rectifier DR is connected with the other end of the buffer inductor LD.

The protection unit includes a third contactor KM3 and a transformer T.

One end of the third contactor KM3 is connected with the output end of the inverter bridge B, the other end of the third contactor KM3 is connected with the low-voltage side of the transformer T, and the high-voltage side of the transformer T is connected with a three-phase power grid.

According to the crane cargo smooth lifting control system based on the double-fed motor, the double-fed motor M, the starting unit, the rotor current control unit, the protection unit and the control circuit are arranged, the starting unit, the rotor current control unit, the protection unit and the control circuit are electrically connected with the double-fed motor M, and the control circuit is used for controlling the action of components in the rotor current control unit, so that the double-fed motor M is controlled in a time-sharing section mode, the cargo smooth lifting of a crane is achieved, and the problems that in the prior art, a frequency converter cannot exert the maximum performance of the frequency converter easily, and only light-load cargo.

Referring to FIG. 2, FIG. 2 shows current i 'fed to the AC bus'_fSchematic of the change over time.

In a second aspect, the invention provides a method for controlling smooth lifting of a crane cargo based on a doubly-fed motor, comprising the following steps:

s1, the control circuit sends out an instruction to control the double-fed motor M to enter a starting state.

S2, an inverter bridge B in the rotor current control unit works at a fixed duty ratio, and the current i 'fed into the alternating current bus by the doubly-fed motor M is controlled by controlling the on-off of a power switch tube S'_f。

S3, adjusting current i 'fed into an alternating current bus'_fTo control the electromagnetic torque of the doubly fed machine M.

And S4, the control circuit controls the double-fed motor M in a time-sharing mode so as to realize smooth lifting of goods.

According to the crane cargo smooth lifting control method based on the doubly-fed motor, the inverter bridge B in the rotor current control unit works at a fixed duty ratio, and the current i 'fed into the alternating current bus by the doubly-fed motor M is controlled by controlling the on-off of the power switch tube S'_fAnd by regulating the current i 'fed to the AC bus'_fThe electromagnetic torque of the double-fed motor M is controlled, the double-fed motor M is controlled in a time-sharing mode through the control circuit, so that the effect of smooth lifting of goods of the crane is achieved, and the problem that in the prior art, a frequency converter cannot exert the maximum performance of the frequency converter and can only achieve lifting of light-load goods is solved.

In S1, the control circuit sends out an instruction to control the doubly-fed motor M to enter a start state, including: the control circuit sends out instructions to close the first contactor KM1, open the second contactor KM2 and open the third contactor KM3, so that the double-fed motor M enters a starting state.

In S4, the control circuit performs time-division control on the doubly-fed motor M, and includes:

s41, when the rotating speed of the double-fed motor M reaches a set value, the control circuit controls the second contactor KM2 to be closed and the third contactor KM3 to be closed, and the duty ratio of a power switch tube S driving signal PMW1 in the rotor current control unit is controlled to enable current i 'fed into the alternating current bus to be fed into'_fAt a constant value to maintain the speed of the doubly fed machine constant. This phase is the low-speed operating phase of the doubly-fed machine M, in which phase it isAnd the fishing rope of the crane is tensioned at a low speed.

S42, when detecting the current i 'fed into the alternating current bus'_fAnd during sudden increase, the first contactor KM1 is switched off, and the current i' f fed into the alternating current bus is reduced by changing the duty ratio of a power switch tube S driving signal PMW1, so that the electromagnetic torque of the double-fed motor M is rapidly increased. The phase is a double-fed motor M rotating speed fast climbing phase.

And S43, when the rotating speed of the double-fed motor M is detected to suddenly increase, the duty ratio of a driving signal PMW1 of the power switch tube S is changed, so that the current i' f fed into the alternating current bus is reduced, and the goods rise in a uniform acceleration motion mode. The phase is a slow speed increasing phase of the doubly-fed motor M.

And S44, when the rotating speed of the double-fed motor M is detected to reach the rated rotating speed, controlling the power switch tube S to be in a conducting state, so that the double-fed motor M operates at the rated rotating speed, and the goods are lifted at the maximum speed at a constant speed. The phase is the stable operation phase of the rotating speed of the doubly-fed motor M.

The cargo of the crane is smoothly lifted through four stages of S41, S42, S43 and S44.

Compared with the prior art, the crane cargo smooth lifting control system and method based on the double-fed motor control device have the advantages that the double-fed motor M, the starting unit, the rotor current control unit, the protection unit and the control circuit are electrically connected with the double-fed motor M, the inverter bridge B in the rotor current control unit works at a fixed duty ratio, and the on-off of the power switch tube S is controlled to control the current i 'fed into the alternating current bus by the double-fed motor M'_fAnd by regulating the current i 'fed to the AC bus'_fThe electromagnetic torque of the double-fed motor M is controlled, the double-fed motor M is controlled in a time-sharing mode through the control circuit, the effect of smooth lifting of goods of the crane is achieved, the problem that in the prior art, a frequency converter cannot exert the maximum performance of the frequency converter easily, and only light-load goods can be lifted is solved, and the application of a double-fed motor speed regulating system in the field of cranes is facilitated.

The above-mentioned embodiments only express several embodiments of the present invention, and the description thereof is more specific and detailed, but not construed as limiting the scope of the invention. It should be noted that, for a person skilled in the art, several variations and modifications can be made without departing from the inventive concept, which falls within the scope of the present invention.