CN111550415B - Driving system and driving control method of steam turbine-motor driven water feeding pump - Google Patents

Abstract

The invention discloses a driving system and a driving control method of a steam turbine-motor driven feed pump, wherein the system comprises: a plurality of current transformers; the steam turbine-motor driving device is connected with the water feeding pump through a first converter and a second converter; the electric driving device is connected with the water feeding pump through a third converter and a second converter, and the electric driving device is connected with the steam turbine-motor driving device through the third converter and the first converter; the steam turbine-motor driving device is used for driving the water feeding pump and grid-connected power generation in a steam turbine driving water feeding pump and power generation operation mode, and the electric driving device is used for driving the water feeding pump in an electric driving water feeding pump starting mode. The invention can ensure that the steam turbine works at the highest efficiency point while realizing the control of the rotating speed of the feed pump, thereby improving the thermal efficiency of the system, and carrying out grid-connected power generation on surplus energy of the system so as to improve the utilization rate of comprehensive energy.

Description

Drive system and drive control method of steam turbine-motor driven feed pump

technical field

The invention relates to the technical field of drive control of a feed water pump, in particular to a drive system of a steam turbine-motor driven feed pump and a drive control method of a steam turbine-motor driven feed pump.

Background technique

In the current thermal power generation, the boiler feed water pump is the most important plant energy-consuming equipment. The common driving method of feed water pump is small steam turbine variable speed drive or electric motor drive, especially for medium and large units in thermal power plants, the small steam turbine drive strategy is widely used.

However, the above driving strategy has the following problems. For example, due to the change of power plant operating conditions, the load of the feed pump will also change accordingly, so that the speed of the power generation system is in a wide range of changes, thus affecting the overall efficiency of the system.

SUMMARY OF THE INVENTION

The present invention aims to solve one of the technical problems in the above technologies at least to a certain extent. Therefore, an object of the present invention is to propose a driving system for a steam turbine-motor to drive a feed water pump, which can ensure that the steam turbine works at the highest efficiency point while realizing the speed control of the feed water pump, thereby improving the thermal efficiency of the system and making the system more efficient. The surplus energy is connected to the grid for power generation to improve the comprehensive energy utilization rate.

The second object of the present invention is to provide a driving control method for a steam turbine-motor driven feed water pump.

In order to achieve the above object, the first aspect of the present invention provides a drive system for a steam turbine-motor driven feed water pump, including: a plurality of converters; The converter and the second converter are connected to the feed water pump; the electric drive device is connected to the feed water pump through the third converter and the second converter, and the electric drive device is connected to the feed pump through the third converter and the second converter. The third converter and the first converter are connected to the steam turbine-motor drive device; wherein, the steam turbine-motor drive device is used for driving the feed water pump and the parallel operation in the steam turbine-driven feed water pump and power generation operation modes Grid power generation, the electric drive device is used for driving the feed water pump in the start mode of the electric drive feed water pump.

According to the driving system of the steam turbine-motor driven feed pump according to the embodiment of the present invention, a plurality of converters, a steam turbine-motor driving device and an electric driving device are provided, wherein the steam turbine-motor driving device passes through the first inverter and the second inverter. The converter is connected to the feed water pump and can be used to drive the feed water pump in the starting mode of the electric drive feed pump. The steam turbine-motor drive device is connected to the feed water pump through the third converter and the second converter, and the electric drive device is connected to the feed pump through the third converter. The steam turbine-motor drive device is connected to the first converter, which can be used to drive the feed water pump and connect to the grid to generate electricity in the operation mode of the steam turbine driving the feed water pump and power generation. Therefore, the thermal efficiency of the system can be improved, and the surplus energy of the system can be connected to the grid for power generation, so as to improve the comprehensive energy utilization rate.

In addition, the drive system of the steam turbine-motor driven feed water pump proposed according to the above examples of the present invention may also have the following additional technical features:

According to an embodiment of the present invention, the steam turbine drives the feed water pump and the power generation operation mode is that when the steam turbine-motor driving device works normally under the starting condition, the energy generated by the steam turbine-motor drive device is transmitted to the The second converter operates to drive the feed water pump, and at the same time, it is transmitted to the third converter through the first converter for grid-connected power generation; the start-up mode of the electric-driven feed water pump is set in the start-up condition. When the steam turbine-motor driving device does not work normally, the electric driving device drives the second converter through the third converter to start the feed water pump.

According to an embodiment of the present invention, the first converter adopts rotor flux linkage oriented control, the outer control loop adopts rotational speed closed-loop control to maintain an optimal speed ratio with high wheel cycle efficiency, and the inner control loop adopts current closed-loop control To adjust the flux linkage and electromagnetic torque of the first motor; the second converter adopts rotor flux linkage directional control, and its control outer loop adopts rotational speed closed-loop control to drive the boiler in the drive system of the feed pump according to the turbine-motor. The water supply demand is to determine the coaxial speed of the water supply pump and the second motor, and the inner control loop adopts current closed-loop control to adjust the flux linkage and electromagnetic torque of the second motor; the third converter adopts Grid voltage oriented control, the outer control loop adopts DC voltage loop to stabilize the DC voltage to adjust the magnitude and flow direction of the transmission power, and the inner control loop adopts AC current loop to adjust the grid-connected power factor as the unit power factor.

Further, the first converter and the second converter are both PWM rectifiers, the first converter and the second converter are connected in parallel with a common DC bus; the third converter The inverter is a PWM inverter, and the third inverter, the first inverter and the second inverter are connected back-to-back through capacitors.

Further, the steam turbine-motor drive device includes a steam turbine and a first motor, the rotor side of the first motor is coaxially connected to the steam turbine, and the stator side of the first motor is connected to the first converter .

Further, the electric drive device includes a filter, a transformer and a second motor, the filter is connected to the power grid through the transformer, and the filter device is connected to the power grid through the third converter and the second converter. The second motor is connected to the feed water pump.

According to an embodiment of the present invention, the second motor and the feed water pump are coaxially connected.

According to an embodiment of the present invention, the first converter is used to control the coaxial rotational speed of the steam turbine and the first motor, and the second converter is used to control the feed water pump and the second motor the coaxial speed.

In order to achieve the above purpose, the second aspect of the present invention provides a drive control method for a steam turbine-motor driven feed pump, comprising the following steps: judging whether the steam turbine-motor drive device works normally under the starting condition; When the steam turbine-motor driving device works normally under the starting condition, the energy generated by the steam turbine-motor driving device is transmitted to the second converter through the first converter to drive the feed water pump to run, and the The first converter is transmitted to the third converter for grid-connected power generation; if the steam turbine-motor drive device does not work normally under the starting condition, the electric drive device is passed through the third converter. A flow converter drives the second converter to activate the feed water pump.

According to the driving control method of the steam turbine-motor driven feed pump according to the embodiment of the present invention, by judging whether the steam turbine-motor driving device works normally under the starting condition, if the steam turbine-motor driving device works normally under the starting condition, then the The energy generated by it is transmitted to the second converter through the first converter to drive the feed water pump, and at the same time, it is transmitted to the third converter through the first converter for grid-connected power generation; if the steam turbine-motor drive device is started When it does not work normally under the working conditions, the second converter is driven by the electric drive device through the third converter to start the feed water pump, so that the speed control of the feed water pump can be realized while ensuring that the steam turbine works at the highest efficiency point. Therefore, the thermal efficiency of the system can be improved, and the surplus energy of the system can be connected to the grid for power generation, so as to improve the comprehensive energy utilization rate.

In addition, the drive control method for the steam turbine-motor driven feed pump proposed according to the above example of the present invention may also have the following additional technical features:

According to an embodiment of the present invention, the first converter adopts rotor flux linkage oriented control, the outer control loop adopts rotational speed closed-loop control to maintain an optimal speed ratio with high wheel cycle efficiency, and the inner control loop adopts current closed-loop control To adjust the flux linkage and electromagnetic torque of the first motor; the second converter adopts rotor flux linkage directional control, and its control outer loop adopts rotational speed closed-loop control to drive the boiler in the drive system of the feed pump according to the turbine-motor. The water supply demand determines the coaxial speed of the water supply pump and the second motor, and the inner control loop adopts current closed-loop control to adjust the flux linkage and electromagnetic torque of the second motor; the third converter adopts the grid voltage Directional control, the outer control loop adopts a DC voltage loop to stabilize the DC voltage to adjust the magnitude and flow direction of the transmission power, and the inner control loop adopts an AC current loop to adjust the grid-connected power factor as a unit power factor.

Description of drawings

1 is a schematic structural diagram of a drive system for a steam turbine-motor-driven feed water pump according to an embodiment of the present invention;

FIG. 2 is a schematic diagram of the operation mode of the driving system of the steam turbine-motor-driven feedwater pump in the start-up mode of the electric-driven feedwater pump according to an embodiment of the present invention;

3 is a schematic diagram of the operation mode of the driving system of the steam turbine-motor-driven feed water pump in an embodiment of the present invention in the steam turbine-driven feed water pump and the power generation operation mode;

4 is a schematic diagram of a control process of a first converter in a drive system of a steam turbine-motor-driven feed water pump according to an embodiment of the present invention;

5 is a schematic diagram of a control process of a second converter in a drive system of a steam turbine-motor-driven feed water pump according to an embodiment of the present invention;

6 is a schematic diagram of a control process of a third converter in a drive system of a steam turbine-motor-driven feed water pump according to an embodiment of the present invention;

FIG. 7 is a flowchart of a driving control method for a steam turbine-motor-driven feed water pump according to an embodiment of the present invention.

Detailed ways

The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, but not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present invention.

FIG. 1 is a schematic structural diagram of a driving system of a steam turbine-motor driving a feed water pump according to an embodiment of the present invention.

As shown in FIG. 1 , the driving system of the steam turbine-motor driven feed pump according to the embodiment of the present invention includes a plurality of converters 10 , a steam turbine-motor driving device 20 and an electric driving device 30 , wherein the plurality of converters 10 include a first A converter 101, a second converter 102 and a third converter 103, the steam turbine-motor drive device 20 is connected to the feed water pump 400 through the first converter 101 and the second converter 102; the electric drive device 30 is connected by The third converter 103 and the second converter 102 are connected to the feed water pump 400 , and the electric drive device 30 is connected to the steam turbine-motor drive device 20 through the third converter 103 and the first converter 101 .

The steam turbine-motor drive device 20 is used to drive the feed water pump 400 and grid-connected to generate electricity in the steam turbine-driven feed water pump and power generation operation modes, and the electric drive device 30 is used to drive the feed water pump 400 in the start mode of the electric drive feed water pump.

In an embodiment of the present invention, both the first converter 101 and the second converter 102 can be PWM rectifiers, and the third converter 103 can be a PWM inverter, wherein, as shown in FIG. A converter 101 and a second converter 102 can be connected in parallel via a common DC bus, and the third converter 103 and the first converter 101 and the second converter 102 can be connected back-to-back via capacitors.

In one embodiment of the present invention, the first converter 101 , the second converter 102 and the third converter 103 may be a two-level voltage source structure.

In another embodiment of the present invention, the first converter 101 , the second converter 102 and the third converter 103 may be a three-level voltage source structure.

In addition, the above-mentioned converter can also be a modular multi-level structure and a cascaded H-bridge type multi-level structure.

In an embodiment of the present invention, as shown in FIG. 1 , the steam turbine-motor driving device 20 may include a steam turbine 201 and a first motor 202, wherein the rotor side of the first motor 202 may be coaxially connected to the steam turbine 201, and the first motor The stator side of the electric machine 202 can be connected to the first converter 101 . The rotor side of the first motor can be coaxially connected to the steam turbine to match the speed parameters, and the stator side of the first motor can be connected to the first converter to match the voltage and current levels.

In one embodiment of the present invention, as shown in FIG. 1 , the electric drive device 30 may include a filter 301 , a transformer 302 and a second motor 303 , wherein the filter may be connected to the power grid 500 through the transformer 302 , and may be connected to the power grid 500 through the third The converter 103 and the second converter 102 are connected to the second motor 303, and the second motor 303 can be connected to the feed water pump. Specifically, the rotor side of the second motor 303 can be connected to the feed water pump 400 coaxially. The stator side of 303 can be connected to the second converter 102 . The rotor side of the second motor can be coaxially connected to the feed pump to match the speed parameters, and the stator side of the second motor can be connected to the second converter to match the voltage and current levels.

In another embodiment of the present invention, the electric drive device 30 may include a filter and a large reactance, wherein the filter may be specifically an LCL filter, and the large reactance may be specifically a smoothing reactor.

In one embodiment of the present invention, the first motor 202 and the second motor 303 may be synchronous motors, wherein, as shown in FIG. 1 , the second motor 303 may also be connected to the feed water pump 400 through the gearbox 600 . By arranging the gear box, the second electric motor can be adapted to the requirement of medium and low rotational speed.

In another embodiment of the present invention, the first motor 202 and the second motor 303 may be asynchronous motors.

It should be noted that the first converter 101 can control the coaxial rotational speed of the steam turbine 201 and the first motor 202 , and the second converter 102 can control the coaxial rotational speed of the feed water pump 400 and the second motor 303 . The converter 101 and the second converter 102 can realize the decoupling of the coaxial rotational speed of the steam turbine 201 and the first motor 202 from the coaxial rotational speed of the feed pump 400 and the second motor 303 , wherein the first converter 101 specifically In order to keep the steam turbine 201 working at the optimum speed ratio according to the relationship between the in-stage circumferential efficiency and the rotational speed of the steam turbine 201 , the second converter 102 can keep the steam turbine-motor driving the feed water pump according to the relationship between the flow rate and the rotational speed of the feed water pump 400 . The demand for water supply to the boiler in the drive system. In addition, the above-mentioned first converter 101 , second converter 102 and third converter 103 may have the capability of bidirectional energy flow, and simultaneously have a passage for energy to be connected to the Internet.

Based on the above structure, the driving system of the steam turbine-motor driven feed water pump of the embodiment of the present invention can realize the drive control of the feed water pump in different driving modes, namely, the electric drive feed water pump start mode, the turbine driven feed water pump and the power generation operation mode.

Among them, the starting mode of the electric-driven feed water pump is that the steam turbine-motor drive device 20 does not work normally under the starting condition, that is, the steam turbine 201 has no steam intake when the driving system of the steam turbine-motor driven feed water pump is in the starting condition; the steam turbine drives the feed water pump and generates electricity. The operation mode is that the steam turbine-motor driving device 20 works normally under the starting condition, that is, the steam turbine 201 works when the driving system of the steam turbine-motor driving the feed water pump is in the starting condition.

Further, as shown in Fig. 2, if the drive system of the steam turbine-motor driven feed pump is in the electric drive feed pump start mode, the steam turbine-motor drive device 20 does not act, the intake valve 2011 of the steam turbine 201 is closed, and the first An inverter 101 , at this time, the electric drive device 30 can drive the second inverter 102 through the third inverter 103 to start the feed water pump 400 .

Further, as shown in FIG. 3 , if the drive system of the steam turbine-motor-driven feed water pump is in the steam turbine-driven feed water pump and power generation operation mode, the steam turbine-motor drive device 20 is actuated, the intake valve 2011 of the steam turbine 201 is opened, and the steam turbine 201 is opened. The rotational speed of its steam turbine 201 is set to the optimal rotational speed ratio. At this time, the energy generated by the steam turbine 201 can be transferred to the second converter 102 through the first converter 101 to drive the feed water pump 400 to run, and at the same time, the energy can be passed through the first converter. 101 is passed to the third converter 103 for grid connection to generate electricity.

To sum up, it can be seen that the driving system of the steam turbine-motor-driven feedwater pump according to the embodiment of the present invention can realize the control of the feedwater pump in different driving modes by controlling the first converter, the second converter and the third converter. drive.

Specifically, the driving system of the steam turbine-motor-driven feed water pump according to the embodiment of the present invention can adjust the generated power and working power generated by the steam turbine 201 by controlling the first converter 101 , the second converter 102 and the third converter 103 . At the same time, the speed of the feed water pump 400 is adjusted to realize multi-directional flow of the generated power, so that the driving system of the steam turbine-motor driving the feed water pump can drive the feed water pump in different driving modes.

More specifically, the driving system of the steam turbine-motor-driven feed water pump according to the embodiment of the present invention can adjust the electromagnetic torque of the first motor 201 and the system input power by controlling the first converter 101, so as to keep the steam turbine 201 running at a constant speed, and The electromagnetic torque of the second motor 303 and the input power of the feed pump 400 can be adjusted by controlling the second converter 102, so as to adjust the speed of the feed pump according to the water supply demand of the boiler in the drive system of the steam turbine-motor driving the feed pump. The third converter 103 adjusts the grid-connected power factor and the DC-side bus voltage, connects the remaining power to the grid, and maintains the DC bus voltage stable.

Among them, the first converter 101 can adopt rotor flux linkage oriented control, its control outer loop can adopt rotational speed closed-loop control to maintain the optimal speed ratio with high wheel cycle efficiency, and its control inner loop can adopt current closed-loop control to adjust the first The flux linkage and electromagnetic torque of the motor 202 . Further, as shown in FIG. 4 , for the first converter 101, a given value of the current speed can be determined through the optimal speed ratio curve of the steam turbine, and then the given value of the speed can be compared with the speed of the first motor 202, The comparison difference is input into the speed regulator without static difference, so that the output speed can follow the given speed value, and at the same time, according to the given speed value, the flux linkage of the first motor 202 can be determined based on the constant magnetic flux or the weakening method. Then the given value of flux linkage can be compared with the flux linkage of the motor, and the comparison difference can be input into the flux linkage regulator without static error. Finally, the output value of the speed regulator and the flux linkage regulator can be used as the control signal. It is input into the first converter 101 to realize the speed control of the steam turbine 201, so that the maximum axle power can be adjusted and obtained.

Among them, the second converter 102 can adopt rotor flux linkage directional control, and its control outer loop can adopt closed-loop speed control to determine the water supply demand of the feed pump and the first For the coaxial rotational speed of the two motors, the inner loop of the control can adopt current closed-loop control to adjust the flux linkage and electromagnetic torque of the second motor 303 . Further, as shown in FIG. 5 , for the second converter 102 , the current feedwater flow rate of the water pump 400 and the working condition curve can determine the current speed given value, and then the given speed value can be compared with the current speed of the second motor 303 . , and input its comparison difference into the speed regulator without static difference, so that the output speed can follow the given speed value, and at the same time, according to the given speed value, the second motor 303 can also be determined based on the constant magnetic flux or the weakening method. The given value of the flux linkage can be compared with the flux linkage of the second motor 303, and the comparison difference can be input into the flux linkage regulator without static error, and finally the machine and the flux linkage can be adjusted according to the speed. The output value of the regulator is input to the second converter 102 as a control signal to realize the speed control of the feed water pump 400, thereby meeting the water supply demand of the boiler in the driving system of the steam turbine-motor driving the feed water pump.

Among them, the third converter 103 can adopt the grid voltage oriented control, its control outer loop can adopt a DC voltage loop to stabilize the DC voltage to adjust the magnitude and flow direction of the transmission power, and its control inner loop can adopt an AC current loop to adjust the grid-connected power The factor is unity power factor. Further, as shown in FIG. 6 , for the third converter 103, the given value of the DC voltage can be compared with the actual value of the DC voltage, and the comparison difference can be input into the active regulator, and at the same time it can be matched with the reactive power regulator. The output controls the third converter 103 to achieve unity power factor adjustment and grid-connected consumption of residual energy. By adjusting the DC voltage through the current converter, the residual power of the system can be connected to the grid to generate electricity, so as to avoid the energy accumulation of the system, realize the utilization of comprehensive energy, and improve the efficiency and operation economy of the system.

According to the driving system of the steam turbine-motor driven feed water pump proposed in the embodiment of the present invention, a plurality of converters, a steam turbine-motor drive device and an electric drive device are provided, wherein the steam turbine-motor drive device passes through the first inverter and the first inverter and the second electric drive device. The second converter is connected to the feed water pump, and can be used to drive the feed pump in the starting mode of the electric drive feed pump. The steam turbine-motor drive device is connected to the feed pump through the third converter and the second converter, and the electric drive device is connected to the feed pump through the third converter. The steam turbine and the first converter are connected to the steam turbine-motor drive device, which can be used to drive the feed water pump and connect to the grid to generate electricity in the operation mode of the steam turbine driving the feed water pump and generating electricity. The highest efficiency point can improve the thermal efficiency of the system, and can connect the surplus energy of the system to the grid to generate electricity, so as to improve the comprehensive energy utilization rate.

Corresponding to the drive train of the steam turbine-motor-driven feedwater pump proposed in the above embodiments, the embodiment of the present invention provides a drive control method for the steam turbine-motor-driven feedwater pump.

As shown in FIG. 7 , the drive control method for the steam turbine-motor driven feed pump according to the embodiment of the present invention includes the following steps:

S1, judging whether the steam turbine-motor driving device works normally under the starting condition.

S2, if the steam turbine-motor driving device works normally under the starting condition, the energy generated by it will be transmitted to the second converter through the first converter to drive the feed water pump to run, and at the same time, it will be transmitted to the second converter through the first converter. The third converter is connected to the grid to generate electricity.

S3, if the steam turbine-motor driving device does not work normally under the starting condition, the electric driving device drives the second converter through the third converter to start the feed water pump.

Specifically, it can be judged whether the steam turbine-motor drive device is working normally according to whether the steam turbine is entering steam under the starting condition. If the steam turbine is entering steam under the starting condition, it can be judged that the steam turbine-motor drive device is working normally; otherwise, the It can be judged that the steam turbine-motor drive device is not working normally, and enter the electric drive feed pump start mode to start the feed pump.

Further, as shown in Fig. 2, if the drive system of the steam turbine-motor driven feed pump is in the electric drive feed pump start mode, the steam turbine-motor drive device does not act, the intake valve 2011 of the steam turbine 201 is closed, and the first Inverter, at this time, the electric drive device can drive the second inverter through the third inverter to start the feed water pump.

Further, as shown in FIG. 3 , if the drive system of the steam turbine-motor-driven feed water pump is in the steam turbine-driven feed water pump and the power generation operation mode, the steam turbine-motor drive device operates, the intake valve of the steam turbine is opened, and the steam turbine of the steam turbine is opened. The rotational speed is set to the optimal rotational speed ratio, at this time the energy generated can be transmitted to the second converter through the first converter to drive the feed water pump, and at the same time, it can be transmitted to the third converter through the first converter Grid-connected power generation.

To sum up, it can be seen that the driving control method for the steam turbine-motor driven feed water pump according to the embodiment of the present invention can realize the control of the feed water pump in different driving modes by controlling the first converter, the second converter and the third converter. drive.

Specifically, the driving control method for a steam turbine-motor-driven feed water pump according to the embodiment of the present invention can adjust the generated power and working power generated by the steam turbine by controlling the first converter, the second converter and the third converter, while adjusting The rotation speed of the feed water pump realizes the multi-directional flow of the generated power, so that the driving control method of the steam turbine-motor driving the feed water pump can drive the feed water pump in different driving modes.

More specifically, the driving control method for the steam turbine-motor driven feed pump according to the embodiment of the present invention can adjust the electromagnetic torque of the first motor and the input power of the system by controlling the first converter, so as to keep the steam turbine running at a constant speed, and can adjust the electromagnetic torque of the first motor and the input power of the system by controlling the first converter. The second converter is controlled to adjust the electromagnetic torque of the second motor and the input power of the feed pump, so as to adjust the speed of the feed pump according to the water supply demand of the boiler in the driving control method of the steam turbine-motor driving the feed pump. The controller adjusts the grid-connected power factor and the DC side bus voltage, connects the remaining power to the grid, and maintains the DC bus voltage stability.

Among them, the first converter can adopt rotor flux linkage directional control, the outer control loop can adopt closed-loop speed control to maintain the optimal speed ratio with high wheel cycle efficiency, and the inner control loop can adopt current closed-loop control to adjust the first motor The flux linkage and electromagnetic torque. Further, as shown in FIG. 4 , for the first converter, the given value of the current rotational speed can be determined through the optimal speed ratio curve of the steam turbine, and then the given value of the rotational speed can be compared with the rotational speed of the first motor, and the difference can be compared. The value is input into the speed regulator with no static difference, so that the output speed can follow the given speed value. At the same time, according to the given speed value, the given value of the flux linkage of the first motor can be determined based on the constant magnetic flux or the weakening method. Then, the given value of flux linkage can be compared with the flux linkage of the motor, and the comparison difference can be input into the flux linkage regulator without static error. In the converter, to realize the speed control of the steam turbine, so that the maximum axle power can be adjusted.

Wherein, the second converter can adopt rotor flux linkage oriented control, and its control outer loop can adopt closed-loop speed control to determine the water supply demand of the boiler according to the driving control method of the steam turbine-motor driving the feed pump to determine the feed pump and the first The coaxial speed of the two motors can be controlled by a current closed-loop control in the inner loop to adjust the flux linkage and electromagnetic torque of the second motor. Further, as shown in FIG. 5 , for the second converter, the current feedwater flow rate of the water supply pump and the working condition curve can be used to determine the current speed given value, and then the speed given value can be compared with the current speed of the second motor. The comparison difference is input into the speed regulator without static difference, so that the output speed can follow the given speed value. At the same time, according to the given speed value, the flux linkage of the second motor can be determined based on the constant magnetic flux or the weakening method. Then the given value of flux linkage can be compared with the flux linkage of the second motor, and the comparison difference can be input into the flux linkage regulator without static error, and finally the output value of the machine and the flux linkage regulator can be adjusted according to the speed. Input the second converter as a control signal to realize the speed control of the feed water pump, so as to meet the water supply demand of the boiler in the driving control method of the steam turbine-motor driving the feed water pump.

Among them, the third converter can adopt grid voltage oriented control, its control outer loop can adopt DC voltage loop to stabilize the DC voltage to adjust the magnitude and flow direction of transmission power, and its control inner loop can adopt AC current loop to adjust the grid-connected power factor is the unity power factor. Further, as shown in FIG. 6 , for the third converter, the given value of the DC voltage can be compared with the actual value of the DC voltage, and the comparison difference can be input into the active regulator, and the output of the reactive regulator can be matched at the same time. The third converter is controlled to achieve unity power factor adjustment and grid-connected consumption of residual energy.

According to the drive control method for the steam turbine-motor driven feed pump proposed in the embodiment of the present invention, by judging whether the steam turbine-motor drive device works normally under the starting condition, if the steam turbine-motor drive device works normally under the starting condition, then The energy generated by it is transmitted to the second converter through the first converter to drive the feed water pump, and at the same time, it is transmitted to the third converter through the first converter to connect to the grid for power generation; if the steam turbine-motor drive device is in When it does not work normally under the starting condition, the second converter is driven by the electric drive device through the third converter to start the feed water pump, so that the speed control of the feed water pump can be realized and the steam turbine can be guaranteed to work at the highest efficiency point. , so that the thermal efficiency of the system can be improved, and the surplus energy of the system can be connected to the grid for power generation, so as to improve the comprehensive energy utilization rate.

In the description of the present invention, the terms "first" and "second" are only used for the purpose of description, and cannot be understood as indicating or implying relative importance or implying the number of indicated technical features. Thus, a feature defined as "first" or "second" may expressly or implicitly include one or more of that feature. "Plurality" means two or more, unless expressly specifically limited otherwise.

In the present invention, unless otherwise expressly specified and limited, the terms "installed", "connected", "connected", "fixed" and other terms should be understood in a broad sense, for example, it may be a fixed connection or a detachable connection , or integrated; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, and it can be the internal connection of the two elements or the interaction relationship between the two elements. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to specific situations.

In the present invention, unless otherwise expressly specified and limited, a first feature "on" or "under" a second feature may be in direct contact between the first and second features, or the first and second features indirectly through an intermediary touch. Also, the first feature being "above", "over" and "above" the second feature may mean that the first feature is directly above or obliquely above the second feature, or simply means that the first feature is level higher than the second feature. The first feature being "below", "below" and "below" the second feature may mean that the first feature is directly below or obliquely below the second feature, or simply means that the first feature has a lower level than the second feature.

In the description of this specification, description with reference to the terms "one embodiment," "some embodiments," "example," "specific example," or "some examples", etc., mean specific features described in connection with the embodiment or example , structure, material or feature is included in at least one embodiment or example of the present invention. In this specification, schematic representations of the above terms are not necessarily directed to the same embodiment or example. Furthermore, the particular features, structures, materials or characteristics described may be combined in any suitable manner in any one or more embodiments or examples. Furthermore, those skilled in the art may combine and combine the different embodiments or examples described in this specification, as well as the features of the different embodiments or examples, without conflicting each other.

Although embodiments of the present invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, and substitutions can be made in these embodiments without departing from the principle and spirit of the invention and modifications, the scope of the present invention is defined by the appended claims and their equivalents.

Claims (2)

1. a drive system of a steam turbine-motor-driven feed water pump, is characterized in that, comprises: multiple converters; a steam turbine-motor drive device, the steam turbine-motor drive device is connected to the feed water pump through the first converter and the second converter; an electric drive device, the electric drive device is connected to the feed water pump through the third inverter and the second inverter, and the electric drive device is connected to the feed pump through the third inverter and the first inverter connecting the steam turbine-motor drive; Wherein, the steam turbine-motor drive device is used for driving the feed water pump and grid-connected power generation when the steam turbine drives the feed water pump and the power generation operation mode, and the electric drive device is used for driving the feed water pump in the start mode of the electric drive feed water pump. water pump; The first converter adopts rotor flux linkage oriented control, its control outer loop adopts rotational speed closed-loop control to maintain the optimal speed ratio of high wheel cycle efficiency, and its control inner loop adopts current closed-loop control to adjust the steam turbine-motor drive The flux linkage and electromagnetic torque of the first motor in the device; The second converter adopts rotor flux linkage oriented control, and its control outer loop adopts rotational speed closed-loop control to determine the feed water pump and the electric drive according to the water supply demand of the boiler in the drive system of the steam turbine-motor driven feed pump. the coaxial speed of the second motor in the device, and the inner loop of the control adopts current closed-loop control to adjust the flux linkage and electromagnetic torque of the second motor; The third converter adopts grid voltage oriented control, its control outer loop adopts DC voltage loop to stabilize the DC voltage to adjust the magnitude and flow direction of transmission power, and its control inner loop adopts AC current loop to adjust the grid-connected power factor as the unit power factor, in, When the steam turbine drives the feed water pump and the power generation operation mode is the start-up condition, when the steam turbine-motor drive device works normally, the energy generated by the steam turbine is transmitted to the second inverter through the first converter to drive the the feed water pump is operated, and at the same time is transmitted to the third converter through the first converter for grid-connected power generation; The starting mode of the electric-driven feed water pump is that when the steam turbine-motor drive device does not work normally under the starting condition, the electric drive device drives the second converter through the third converter to start the feed pump, in, The first converter and the second converter are both PWM rectifiers, and the first converter and the second converter are connected in parallel with a common DC bus; The third converter is a PWM inverter, and the third converter, the first converter and the second converter are connected back-to-back through capacitors, The steam turbine-motor drive device further includes a steam turbine, the rotor side of the first motor is coaxially connected to the steam turbine, and the stator side of the first motor is connected to the first converter, The electric drive device further includes a filter and a transformer, the filter is connected to the grid through the transformer, and the filter device is connected to the second motor through the third converter and the second converter , the second motor is connected to the feed water pump, Wherein, the second motor and the feed water pump are coaxially connected, Wherein, the first converter is used to control the coaxial rotational speed of the steam turbine and the first motor, and the second converter is used to control the coaxial rotational speed of the feed water pump and the second motor. 2. A drive control method for a steam turbine-motor-driven feed water pump, comprising the drive system of the steam turbine-motor-driven feed water pump according to claim 1, characterized in that, comprising the following steps: Judging whether the steam turbine-motor driving device works normally under the starting condition; If the steam turbine-motor driving device works normally under the starting condition, the energy generated by the steam turbine-motor driving device is transmitted to the second converter through the first converter to drive the feed water pump to run, and at the same time, the energy generated by the steam turbine-motor driving device is transmitted to the second converter through the first converter to drive the operation of the feed water pump. the first converter is transmitted to the third converter for grid-connected power generation; If the steam turbine-motor driving device does not work normally under the starting condition, driving the second converter through the third converter through the electric driving device to start the feed water pump; The first converter adopts rotor flux linkage directional control, the outer control loop adopts rotational speed closed-loop control to maintain the optimal speed ratio with high wheel cycle efficiency, and the inner control loop adopts current closed-loop control to adjust the steam turbine- The first motor flux linkage and electromagnetic torque in the motor drive device; The second converter adopts rotor flux linkage oriented control, and its control outer loop adopts rotational speed closed-loop control to determine the difference between the feed water pump and the electric drive device according to the water supply demand of the boiler in the drive system of the steam turbine-motor driven feed pump. The coaxial speed of the second motor, the inner loop of its control adopts current closed-loop control to adjust the flux linkage and electromagnetic torque of the second motor; The third converter adopts grid voltage oriented control, and its control outer loop adopts DC voltage loop to stabilize the DC voltage to adjust the magnitude and flow direction of transmission power, and its control inner loop adopts AC current loop to adjust the grid-connected power factor as the unit power. factor.

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