CN102088272B - 10kV digital high-voltage stator variable voltage control device - Google Patents

Abstract

The invention provides a 10kV digital high-voltage stator variable voltage control device, which comprises a stator control device, a rotor control device, a brake device and a safety device of an engine. The 10kV digital high-voltage stator variable voltage control device is characterized in that: the stator control device of the engine comprises a controlled silicon component (9) which is connected to a stator wiring terminal of the engine, a forward and reverse trigger (2) and a control system thereof, wherein the output end of the forward and reverse trigger (2) is connected with each controlled silicon trigger electrode in the controlled silicon component (9); the control system is connected with the input end of the forward and reverse trigger (2); and in the controlled silicon component (9), multiple grades of forward and reverse controlled silicon are connected in series into a group, each phase of the wiring terminal of the engine stator connects one group of the controlled silicon to a phase of a power supply end or connects two groups of controlled silicon in parallel to two phases of power supply ends respectively. The 10kV digital high-voltage stator variable voltage control device can ensure that more or a plurality of wound asynchronous motors with voltage of between 1 and 10kV and current range of between 50 and 2,000A perform stable variable voltage control under large starting torque, and has the characteristics of energy saving, high dynamic property, high accuracy, high response speed and the like.

Description

10kV Digital High Voltage Stator Voltage Regulator and Speed Regulator

technical field

The invention relates to a motor speed regulating device, in particular to a thyristor stator voltage regulating and speed regulating device of a high-voltage winding motor.

Background technique

Due to historical reasons, AC motors with a capacity of more than 450-500KW in my country's traditional industries are powered by high voltage, and most of them operate in "single speed". In the case where it is necessary to ensure large starting torque and speed regulation, such as hoisting, the traditional method is to use a wound asynchronous motor to use rotor series resistance for speed regulation, and the stator terminal is connected to a frequency converter for frequency conversion speed regulation and an adjustable additional potential is connected in series to the rotor circuit. Cascade speed regulation and other methods.

The rotor series resistor speed regulation of asynchronous motor is to obtain different mechanical characteristics by connecting resistors of different values in series through the contactor, so as to realize the speed regulation of electric drag. Although the starting current can be reduced to 3 to 5 times the rated current (the direct starting current is about 5 to 7 times the rated current) to ensure a large starting torque, it still has a large impact on the circuit and mechanical structure, starting, stopping and shifting When the speed changes discontinuously, precise positioning cannot be realized, the speed is related to the load, and the speed closed loop cannot be realized.

If the frequency conversion speed regulation of the motor stator power supply is changed to change its synchronous speed, large torque, low starting current, precise speed regulation and energy saving can be realized, but its technology is complicated. According to the composition structure of the current general frequency conversion speed regulation system , the inverter must be connected to the stator side of the motor and its capacity must be greater than or equal to the motor capacity. The foundation of my country's semiconductor industry is weak. At present, we do not have the conditions to independently develop or manufacture high-voltage and large-capacity AC-DC-AC inverters required for self-shutoff devices and their supporting large-scale integrated control circuit chips, inverter power components IGBT and IGCT is subject to technical blockade abroad, and the country is still unable to manufacture it. Therefore, if frequency conversion speed regulation technology is used in high-voltage large motors, it is necessary to import high-voltage large-capacity frequency converters from abroad. Such frequency converters are expensive, and it is very difficult to popularize or promote their use. . In addition, the inverter output uses power components for high-speed switching, and the output current contains a large number of high-order harmonics. Conventional motors can easily cause excessive motor shaft current to ablate the motor bearings. High dv/dt makes the insulation requirements of the motor very high. Subharmonics are very easy to pollute the power grid and interfere with the normal operation of other equipment. It is often necessary to install isolation transformers, filters, reactors, reactive power compensation, etc., which further increase the cost.

Cascade speed regulation achieves the purpose of speed regulation by adding an adjustable additional potential in series to the rotor circuit to change the slip of the motor. Most of the slip power is absorbed by the additional potential connected in series, and then used to generate additional devices to return the absorbed slip power to the grid or convert energy for use, although this speed regulation method can reduce the slip loss during the speed regulation process Feedback to the grid, but there are low system power factor, large harmonic influence, small adjustment range (70% to 90% of rated speed), slow dynamic response, and generally need to increase the step-up transformer for feedback, and the system failure rate is relatively low. High disadvantage. As the current cascade speed regulation technology is still immature, it has not been widely used.

Contents of the invention

Aiming at the above-mentioned problems in motor speed regulation, the technical problem to be solved by the speed regulating device of the present invention is to regulate the speed of a wound-type asynchronous motor with an operating voltage of 1 kV to 10 kV and a rated current of 50 to 2000A. The speed range can be set by parameters, and the continuous speed control irrelevant to the load can be realized within the closed loop range. Quadrant drive operation, reliable electronic rotating field commutation. Solve the problems of high price, low voltage regulation accuracy, slow dynamic response, narrow speed regulation range, large mechanical impact, no energy saving, low power factor, and large harmonic influence in the aforementioned three voltage regulation technologies.

A 10kV digital high-voltage stator voltage-regulating and speed-regulating device, including a motor stator control device, a rotor control device, a braking device and a safety device, is characterized in that: the motor stator control device includes an adjustable A silicon-controlled component, a forward and reverse flip-flop whose output terminal is connected to each thyristor trigger pole in the thyristor component, and a control system connected to an input terminal of the forward-reverse flip-flop, and the thyristor component There are multiple groups, each group is multi-stage positive and negative thyristors connected in series, and each phase terminal of the motor stator is connected to a group of thyristor components to a phase power supply terminal or two sets of thyristor components are connected to each other in parallel. Two-phase power supply terminal; the stator control device of the motor also includes a crane operation control process module, the U663 port of the crane operation control process module is connected to the speed controller through the start pulse module, and the output terminal of the speed controller is connected to the single pole One contact of the double-throw switch is connected, the other contact of the single-pole double-throw switch is connected with the 100% node, the boom of the single-pole double-throw switch is connected with the current limiting module, and the output terminal of the current limiting module is connected with the The given quantity input terminal of the current controller is connected, the output terminal of the current controller is connected with the input terminal of the gate control unit; the U605 port of the crane operation control process module is connected with the control terminal of the single-pole double-throw switch.

According to the level of the power supply voltage, different numbers of thyristor components are used for series voltage division to reduce the actual voltage borne by each thyristor, and the phase angle of the associated thyristor components is changed synchronously through the intelligent system to adjust the stator main circuit. Voltage, and then through closed-loop control to achieve continuous regulation of 0 ~ ± 60% speed that has nothing to do with the load.

The present invention also has the following optimization scheme, the rotor control device includes a multi-stage rotor resistance connected in series to each phase terminal of the rotor, a rotor contactor for switching each stage of the rotor resistance, and a rotor contactor controller, and each stage of the rotor resistance is connected in parallel with a A group of rotor contactors, the wire package of each rotor contactor is serially connected to the corresponding rotor contactor controller. Outside the speed range of ±60%, the rotor resistance is switched by open-loop control to accelerate.

The stator control of the electric motor includes a closed-loop control of the current.

The stator control of the electric motor includes a closed-loop control of the speed.

The speed closed-loop control device uses a tachogenerator as a speed feedback link.

The safety device includes a power supply transient protector, a phase protector, a limit protector, and a temperature monitor.

A scheme combining stator phase angle control and motor rotor switching resistance control is adopted. In the set closed-loop range (generally -60% to +60% of the rated speed), the load-independent continuous speed control is realized, and the speed outside this range is accelerated by switching the rotor resistance. In the acceleration process from stationary to full-speed operation, the closed-loop control process is the first. When the system is working, the signal is first sent out by the speed setter, and its size determines the speed of the motor. The given signal is subtracted from the feedback signal of _the encoder or tachogenerator, that is, ΔU=U _to -U, the difference ΔU is sent to the regulator, and the output of the regulator is sent to the trigger to make it output a pulse with a certain phase displacement , the thyristor outputs a certain voltage, so that the speed of the motor adapts to the given value. If the actual speed of the system is lower than the value corresponding to the given signal due to some reason (such as the load becomes larger), the voltage fed back by the tachometer generator will drop, so that the input and output of the regulator will increase, and the pulse sent by the trigger will Shift, forcing the SCR output voltage to rise, the motor speed increases, and stabilizes at the required speed, then the stator voltage remains unchanged; and vice versa.

Basic principle of the present invention:

The 10kV digital high-voltage stator voltage and speed control device is a compact three-phase thyristor phase angle controller, which can control single or multiple wound asynchronous motors in closed-loop and open-loop states. The stator voltage regulating speed regulating device generates counter torque through two sets of additional thyristors, and the trigger board controls the on-off of the thyristors, so that the motor can run in four quadrants, and the stator voltage of the motor can be changed under the action of the stator phase angle control to achieve speed regulation The purpose, but the motor is still using a frequency of 50Hz alternating current.

Stator Phase Angle Control

Stator phase angle control is achieved by changing the fundamental amplitude of the line voltage. The given voltage increases continuously from zero to the maximum according to a certain slope, and the phase angle and control time also increase continuously, so that the stator voltage of the motor also increases continuously, so the speed also increases, and the torque of the motor increases in proportion to the square of the stator voltage . Figure 1 shows the speed-torque characteristic curve of the asynchronous motor controlled by the stator phase angle. In the figure, n ₀ is the synchronous speed, n _N is the normal operating point speed, M _A is the starting torque without stator phase angle control, M _M is the motor torque, MA* is the starting torque with stator phase angle control, M* is the instantaneous characteristic of the motor, and M _B * is the acceleration torque.

Rotor Switching Resistance Control

The torque of the motor is changed by switching the rotor resistance. For a fixed load, changing the resistance will result in different fixed speeds n2, n3, n4, and similarly, the speed will also change when the load changes. When the speed is low, most of the output power of the rotor is converted into heat and consumed on the external resistance of the rotor to avoid overheating of the motor at low speed. Figure 2 shows the speed-torque characteristic curves of the motor when the rotor resistance is different. In the figure, A is the short-circuit characteristic curve of the motor rotor, B, C, and D are the characteristic curves of the series resistance of the motor rotor. The meanings of the marks in the figure are the same as those in Figure 1.

The present invention also adopts electronic reverse braking mode

Assuming that the system drags a constant load, accelerates at a positive speed and runs stably at point a, the motor is in an electric state. If there is a deceleration or reverse order at this time, the stator voltage regulation speed control device will block the forward thyristor group and trigger the reverse thyristor group at the same time, change the phase sequence of the output voltage, switch to the reverse torque operation mode, and run at point b. The electric motor is in the dynamic braking state and begins to decelerate. At this time, the slip value of the motor is s=2, and the stator voltage regulating speed regulating device outputs full voltage. The current of the motor is greater than the starting current, therefore, the stator voltage regulating speed control device automatically reduces the output voltage immediately, and at the same time allows all rotor resistances to be connected to limit the maximum current. Figure 3 shows the speed-torque characteristic curve during electronic reverse braking. The meanings of the marks in the figure are the same as those in Figure 1.

The invention can stably regulate the speed of single or multiple wound asynchronous motors with a voltage of 1 kV to 10 kV and a current range of 50A to 2000A while ensuring a large starting torque, and has energy saving, high dynamic characteristics and high precision , fast response, etc., and has the following advantages:

(1) Safety, high dynamic characteristics, convenient operation, general purpose and easy operation;

(2) It can be used in harsh environments, runs smoothly, reduces the impact on the system, and has high dynamic control performance and control accuracy;

(3) It is a very effective transmission solution for the transformation of the old motor system; when it is used in the solution of the new system, its cost performance is also more advantageous; the upgrade is very convenient, so that the existing system can be significantly improved, and the transformation cost Low.

(4) The control function is integrated, and the requirements for contactor control and external interlocking conditions are low; design planning and configuration operations are less.

(5) Four-quadrant driving operation, stator phase angle control, commutation through reliable electronic rotating magnetic field.

(6) The device adopts a direct connection structure, which reduces the time and frequency of assembly and debugging, thereby saving investment.

The invention fills up the blank of the 1kV-10kV high-voltage winding type asynchronous motor voltage regulation and speed regulation system, and is especially suitable for hoisting occasions such as mines and deep wells.

Description of drawings

Figure 1 is the speed-torque characteristic curve of the asynchronous motor controlled by the stator phase angle,

Figure 2 is the speed-torque characteristic curve of the motor when the rotor resistance is different,

Figure 3 is the speed-torque characteristic curve during electronic reverse braking,

Figure 4 is a block diagram of the closed-loop control principle of voltage regulation and speed regulation.

Figure 5 is a structural block diagram of the motor speed control system,

Figure 6 is a schematic diagram of the stator main circuit circuit,

Figure 7 is a typical wiring diagram for speed regulation with switching value.

Figure 8 is a typical wiring diagram for speed regulation with analog switches.

In the figure: 1-A1 group of thyristor components, 2-positive and negative phase trigger, 3-A2 group of thyristor components, 4-B group of thyristor components, 5-motor, 6-C2 group of thyristor components , 7-C1 thyristor components, 8-rotor control device, 9-thyristor components, 10-gate control unit, 11-current detector, 12-current controller, 13-tacho generator, 14-current Follower, 15-speed controller, 16-rotor contactor controller, 17-rotor contactor, 18-rotor resistance, 19-temperature monitor, 20-power supply transient protector, 21-phase protector, 22- limit protector.

Detailed ways

The present invention is further described below in conjunction with accompanying drawing and embodiment: described 10kV digital high-voltage stator voltage regulating speed regulating device, comprises the stator control device of electric motor, rotor control device, braking device and safety device, as shown in Figure 6, the The stator control device of the motor includes a thyristor assembly 9 connected to the motor stator terminal, a forward and reverse flip-flop 2 connected with each thyristor trigger pole in the thyristor assembly 9, and a forward and reverse The control system connected to the input end of the trigger 2, the thyristor assembly 9 has multiple groups, each group is multi-stage forward and reverse thyristor connected in series, and each phase terminal of the motor stator is connected to a group of controllable rectifiers. The silicon component is connected to the one-phase power supply terminal or two groups of thyristor components are connected in parallel to the two-phase power supply terminal respectively. According to the level of the power supply voltage, different numbers of thyristor components 9 are used for series voltage division to reduce the actual voltage borne by each thyristor, and the phase angle of the associated thyristor components 9 is synchronously changed by the intelligent system to adjust the main stator. The voltage of the loop, and then through the closed-loop control, the continuous adjustment of the speed of 0~±60% has nothing to do with the load.

As shown in FIGS. 7 and 8 , the rotor control device 8 includes a multi-stage rotor resistance 18 connected in series at each phase terminal of the rotor, a rotor contactor 17 for switching each stage of the rotor resistance 18 , and a rotor contactor controller 16 . Outside the speed range of ±60%, the rotor resistance is switched by open-loop control to accelerate.

As shown in Fig. 4, the stator control device of the motor includes a closed-loop control device for current.

The stator control of the electric motor includes a closed-loop control of the speed.

The speed closed-loop control device uses the tachogenerator 13 as a speed feedback link.

The safety device includes a power supply transient protector 20 , a phase protector 21 , a limit protector 22 and a temperature monitor 19 . Before the system works, the safety circuit should monitor whether there are faults such as phase sequence error, extreme phase imbalance and excessive voltage drop of three-phase power supply. Provide electrical interlocking to ensure that in the event of power supply failure, phase sequence error, abnormal brake feedback status, overheating, etc., the alarm signal is output and the pulse is blocked internally. When the fault is not eliminated, the alarm signal appears again after reset, and the motor cannot run . The block diagram of the entire motor speed control system is shown in Figure 5.

The device outputs a switch signal to control the rotor contactor 17, so as to control the switching of the rotor resistance 18 to match the speed regulation. The speed setting adopts the stepless setting of the master controller or the stepless setting of the analog quantity, and uses the tachometer generator 13 to realize the speed feedback to form a closed-loop speed regulation system. The speed can be adjusted in four quadrants. When the actual speed rises to the set point of the open-loop control process, the master control starts to issue an instruction to switch the first-stage rotor resistance. As the actual speed continues to increase, the second, third, and fourth-stage rotor resistances are gradually switched. . When switching the rotor resistance, the device will block the trigger pulse according to the preset time, thereby reducing the instantaneous intensity of the torque, ensuring that the mechanical parts, power grid, motor, and device will not be subject to large impacts, and at the same time ensuring that the rotor contactor 17 contacts The point operates under the no-load state, which greatly prolongs the life of the contacts of the rotor contactor 17.

Since the stator is powered by high voltage, the main circuit of the stator is composed of 12 pairs of anti-parallel thyristors and forward and reverse triggers (see the combination of A1, B, C1 or A2, B, C2 in Figure 6), and the phase angle of the thyristor The control is used to change the voltage applied to the motor. The trigger commutates the stator power supply, and through logic control, when the trigger commutates, it automatically switches in the state of no current. In Figure 6, the thyristor phase angle control and positive Inverting flip-flops make up the gating circuits in Figures 7 and 8. Since the motor torque is proportional to the square of the stator voltage, the control circuit changes the stator voltage of the motor by changing the firing angle of the thyristors of each phase in series in the three phases. The trigger circuit board we use can trigger the thyristor under any rated harsh conditions, which can completely solve the problems of temperature drift and false triggering of the thyristor, and the capacity of the triggered thyristor can also reach 3000 amperes.

The device abandons the traditional contactor reversing method and adopts built-in electronic reversing to ensure the dynamic response speed and accuracy. The acceleration and deceleration of the motor has a configurable acceleration and deceleration slope to ensure the smooth speed change of the motor and minimize the mechanical impact on the motor and gearbox. In addition, the device is very comprehensive in terms of safety. The action of the brake is given by the device, and the state of the brake is monitored at all times. When it is abnormal, it will be blocked and a fault signal will be given at the same time. When the device starts, the signal to open the brake will be given after the starting torque is established in advance to prevent the hook from starting. When stopping, electric braking is performed first, followed by mechanical braking. When the speed is reduced to the set value, a braking signal is given, but the device continues to output current for a period of time until the motor stops rotating to generate torque to stabilize the motor, ensuring that the brake acts when the motor has almost no relative rotation when the motor stops, and there is sufficient Time allows the mechanical stroke of the brake to be in place, which minimizes mechanical wear, prolongs the life of the friction plate, and effectively prevents the parking hook phenomenon caused when the mechanical stroke of the brake is not fully in place. The traditional braking method generally does not have the above functions, and almost completely relies on the mechanical friction of the brake to achieve deceleration and parking. The life of the brake friction plate is very short, and it is often necessary to adjust the gap and replace the friction plate, which poses a large safety hazard.

Examples of speed regulation controlled by analog quantity and speed regulation controlled by switch quantity (such as hoisting mechanism and translation mechanism) are shown in Fig. 8 and Fig. 7 respectively.

(1) Speed given

As shown in Figure 8, stepless setting of speed is realized through the analog input terminals of the control board, as shown in Figure 7, multi-stage speed setting is realized through the digital input terminals of the control board.

(2) Speed feedback

The analog tachogenerator 13 or digital encoder is used to directly connect to the corresponding terminals on the control board.

(3) Motor temperature protection

The temperature monitor 19 can be composed of various commonly used motor temperature protection components such as KTY or PTC.

(4) Brake control

Through the logic control inside the device, the actual speed is detected, the brake is turned off when the motor is basically at the preset minimum speed, and the motor current is turned off after a delay, which greatly improves the safety performance and reduces mechanical wear. However, during an emergency stop, the brake is immediately closed without detecting the actual speed value.

(5) Speed regulator

By adjusting the value of the PI (proportional-integral) regulator, adjust the response time and adjustment time of the speed.

(6) Starting pulse

For the hoisting mechanism, the size of the starting pulse can be set, so that the motor generates an upward torque before the brake is opened, and the load will not slide down.

(7) Motor commutation and rotor switching resistance

Through internal logic control, the device automatically controls the switching rotor contactor 17 when it detects that the actual speed of the motor fed back by the tachometer reaches the set contactor action value, so that the motor uses different speed-torque characteristic curves at different speeds ( See Figure 2), to ensure speed and torque. When the rotor contactor 17 is in action, the trigger pulse is blocked for a short time to realize switching when there is no current, and to prolong the service life of the contacts of the rotor contactor 17 . details as follows:

As shown in Figure 6, the device has built-in 5 thyristor components, which are A1, A2, B, C1, and C2. The combination of A1, B, and C1 is the thyristor group that drives the motor in the forward direction. The combination of A2, B, and C2 is a silicon controlled rectifier group that drives the motor in reverse, through the use of different silicon controlled rectifier groups to realize electronic control of positive and negative rotation and braking.

Starting and accelerating in the upward direction: In the standby state, the device sends an instruction to make S1 in the closed state, the rotor contactor KM1 is closed, and the rotor resistance R0 is short-circuited. When the device uses a positive electric thyristor group, that is, A1, B, C1 thyristor, the operation of the motor follows the torque-speed characteristic curve C in Figure 2, according to the given speed and the actual load size and the set start pulse Size, the device controls the conduction angle of the silicon controlled rectifiers A1, B, and C1, and the motor rotates forward. At the same time, the device detects the feedback speed. If the speed is lower than the given speed, it will turn on without exceeding the set maximum current. Increase the conduction angle to increase the motor voltage until the speed increases to the given speed. If the speed exceeds the given speed, the device will reduce the conduction angle and reduce the speed until it is equal to the given speed. Whether the rotor contactor operates is related to the corresponding speed value set when the action is set. If the given speed is 60%, and the corresponding speed value set by S2 is 55%, then S2 will be closed when the actual speed of the motor rises to 55%. At this time Refer to the characteristic curve B in Figure 2 for the operation of the motor, and the conduction angle of the thyristor is adjusted according to the actual feedback speed. If the master command gives a full speed command, the device will gradually increase the conduction angle until the full voltage output when the speed exceeds the set closed-loop range. It will block the SCR trigger pulse for a short time (configurable), realize no current switching of the rotor contactor, and reduce the impact on machinery and circuits. At this time, the device is in an open-loop operation state.

Deceleration in the ascending direction and return to zero position: When the main command is downshifted from a high-speed upshift or returns to zero, the device will immediately block the forward electric thyristor group, open the reverse electric thyristor group A2, B, C2, and perform reverse connection Brake, disconnect all rotor contactors at the same time, so that all resistors are connected to the rotor circuit, to achieve the maximum reverse torque output, and because the resistance connected to the rotor circuit is the largest, it ensures that the current of the stator circuit will not be too large, and the device will Under the premise of not exceeding the maximum current limit, the conduction angle is controlled to output as high a voltage as possible, so that the motor speed follows the set descending slope to achieve rapid deceleration and braking.

Start and accelerate in the descending direction: when the master command gives a descending command, the SCR groups A1, B, and C1 in the forward direction are turned on first, and S1, S2, S3, and S4 are all disconnected. At this time, the device belongs to the reverse connection system. When the weight is in the falling state, adjust the conduction angle according to the feedback speed to realize the regulation of the stator voltage, so that the actual speed reaches a given value. When the master command issues a full-speed descending command, the device will block the normal speed when the actual speed exceeds the set closed-loop range. To the electric thyristor group, turn on the reverse electric thyristor group A2, B, C2, and gradually make the thyristor fully conduction, the contactor is closed sequentially according to the set contactor action value, at this time the load drives the motor to exceed Synchronous speed rotation, the motor is in the state of reverse power generation.

Downshifting in the down direction and returning to zero position: when the main command changes from high-speed down to low-speed down or zero or up, the device immediately blocks the thyristor groups A2, B, and C2, and at the same time turns on the thyristor groups A1, B, and C1 and Disconnect all rotor contactors, perform reverse braking, and also adjust the conduction angle to output the highest possible voltage under the condition that the current does not exceed the set maximum current. Since all the rotor circuit resistances are connected, the relative current is guaranteed to be the lowest. hour braking torque maximum. When the speed drops to the given value of the main command, adjust the output according to the different situations described above.

(8) Limit protection

The input limit signal is controlled by the limit protector 22 inside the device to decelerate or stop the motor.

Claims (6)

1. the digital high pressure stator variable voltage speed control of 10kV device, the stator control device that comprises motor, the rotor control device, brake apparatus and safety device, it is characterized in that: the stator control device of described motor comprises the silicon controlled component (9) that is connected the motor stator terminals, forward and reverse trigger (2) that output is connected with each controllable silicon trigger electrode in the silicon controlled component (9), the control system that is connected with input with forward and reverse trigger (2), described silicon controlled component (9) has many groups, each group is multistage forward and reverse controllable silicon series connection, each of motor stator join line end connect one group of silicon controlled component to a phase feeder ear or and connect two groups of silicon controlled components and be connected respectively to the two-phase feeder ear; The stator control device of described motor also comprises crane operation control technical module, the U663 port of described crane operation control technical module is connected with speed control by the starting impulse module, the output of described speed control is connected with a contact of single-pole double-throw switch (SPDT), another contact of described single-pole double-throw switch (SPDT) is connected with 100% node, the swing arm of described single-pole double-throw switch (SPDT) limits module with electric current and is connected, the output that described electric current limits module is connected with the specified rate input of current controller, and the output of described current controller is connected with the input of door control unit; The U605 port of described crane operation control technical module is connected with the control end of described single-pole double-throw switch (SPDT).

2. the digital high pressure stator variable voltage speed control of 10kV according to claim 1 device, it is characterized in that: described rotor control device (8) comprises and is connected on rotor whenever join the multi-stage rotor resistance (18) of line end, rotor contactor (17) and the rotor contactor controller (16) of every grade of rotor resistance of switching (18), each grade rotor resistance (18) is parallel with a group rotor contactor (17), and the line bag of each rotor contactor (17) seals in corresponding rotor contactor controller (16).

3. the digital high pressure stator variable voltage speed control of 10kV according to claim 1 and 2 device, it is characterized in that: the stator control device of described motor comprises the closed-loop control device of electric current.

4. the digital high pressure stator variable voltage speed control of 10kV according to claim 1 and 2 device, it is characterized in that: the stator control device of described motor comprises the closed-loop control device of speed.

5. the digital high pressure stator variable voltage speed control of 10kV according to claim 4 device is characterized in that: the closed-loop control device of described speed uses encoder or tachogenerator (13) as the speed feedback link.

6. the digital high pressure stator variable voltage speed control of 10kV according to claim 1 device is characterized in that: described safety device comprises power supply transient protective device (20), phase protection device (21), position limitation protection device (22), temperature monitoring (19).

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