Shaft power generation device with reactive compensation function

Abstract

The invention provides an axle generator with a reactive compensation function, which comprises a machine side rectifier, a network side inverter and an axle generator controller, the alternating current side of the machine side rectifier is connected with the output of an axle motor, the direct current side of the machine side rectifier is connected with the direct current of the network side inverter, and the machine side rectifier and an axle generator control system perform data interaction. The reusability of the axle power generation device is increased, and when the host does not meet the power generation requirement, the axle power generation device can be switched to a reactive compensation mode; the shaft-driven power generation device provides reactive power for a ship power grid, so that the performance of the generator set is prevented from being influenced by reactive power impact of a ship load; power factors of the generator set are improved, output current of the generator set is reduced, operation efficiency of the generator set is effectively improved, and oil consumption of the generator set is reduced Large hardware modification is not needed, only several groups of current sampling CTs need to be added, and the cost performance is high.

Description

Technical Field

[0001] The invention relates to the technical field of vibration reduction and noise reduction of internal combustion engines, and in particular to a shaft-driven generator with a reactive power compensation function. Background Art

[0002] The ship's shaft-driven generator is a device that converts the main engine's surplus power into electrical energy to supply power to the ship's power grid. The use of the shaft-driven generator can improve the utilization rate of the main engine on the one hand, and save the configuration of the diesel generator set on the other hand, achieving a fuel-saving effect.

[0003] Patent CN208209525U provides a shaft-belt generator system that can be coordinated with AC and DC busbars. The corresponding charging and discharging of battery components can compensate for the power supply fluctuations of the shaft-belt generator system and the power grid fluctuations caused by the main engine propulsion load fluctuations, quickly compensate for the power grid load fluctuations, and quickly compensate for the power grid load fluctuations, thereby reducing the response speed requirements for the power generation prime mover, reducing the high-frequency fluctuations of the generator, reducing the number of starts and stops of the generator, and reducing maintenance costs.

[0004] However, it mainly solves the grid fluctuations caused by load fluctuations by configuring a battery system in the system. It is mentioned that in the PTO (Power-Take-Off) mode, reactive power can be injected into the grid to adjust the reactive power of the grid.

[0005] Since the grid side of the shaft-driven generator adopts the inverter form, it has the function of reactive power injection. However, this reactive power injection function can not only adjust the grid fluctuation problem under the PTO mode, but also have further application in the fuel saving problem of diesel generator sets. Summary of the invention

[0006] In response to the problems existing in the prior art, the present application proposes a shaft-belt generator with a reactive power compensation function. The shaft-belt generator with a reactive power compensation function includes: a machine-side rectifier, a grid-side inverter, and a shaft generator controller. The AC side of the machine-side rectifier is connected to the output of the shaft-belt motor, the DC side of the machine-side rectifier is connected to the DC side of the grid-side inverter, and the machine-side rectifier exchanges data with the shaft generator control system.

[0007] Furthermore, the DC side of the grid-side inverter is connected to the DC side of the machine-side rectifier, and the AC side of the grid-side inverter is connected to the incoming switch of the ship's AC distribution panel, and is connected to the ship's power grid through the AC distribution panel. The grid-side inverter exchanges data with the shaft generator control system.

[0008] Furthermore, it also includes a generator side sampling CT, which is installed at the output end of the marine generator set, and its secondary side output is sent to the analog input of the shaft generator control system.

[0009] Furthermore, the shaft generator control system exchanges data with the machine-side rectifier and grid-side inverter through communication, and simultaneously samples the output current of the marine generator set and the grid voltage.

[0010] Furthermore, when the host meets the power generation requirements, the shaft-driven generator operates in PTO mode, the machine-side rectifier maintains the DC bus voltage, and the grid-side inverter adopts a droop control strategy to output the voltage source and connect the generator set to the grid.

[0011] Furthermore, when the host does not meet the power generation requirements, the machine-side rectifier stops working and the grid-side works in reactive power compensation mode, with the control target being that the output power factor of the diesel generator set is close to 1.

[0012] Furthermore, when the host does not meet the power generation conditions, the machine-side rectifier stops working, and the grid-side inverter switches to the reactive compensation mode. The output current of the generator set is detected, and the reactive current of the generator set is extracted through coordinate transformation. The sum of the reactive currents of multiple generator sets is used as the outer loop control object of the grid-side inverter control loop, and the control target is that the sum of the reactive currents of the generator sets is 0.

[0013] Furthermore, the reactive current sum of the generator set is 0, and the output is obtained by the grid-side inverter control inner loop. The control object of the inner loop control is the grid-side inverter output current, and the output target is that the grid-side inverter output current active power is 0, and the reactive power is the output of the outer loop control.

[0014] Furthermore, after adopting this control, the power factor of the conventional marine load is 0.8, and the output power factor of the generator set is increased from 0.8 to close to 1 through the compensation effect of the shaft belt generator.

[0015] Furthermore, the generator set only provides active power to the load, and the shaft-driven generator device provides reactive power to the load.

[0016] The shaft-driven generator with reactive power compensation function provided by the present invention has the following beneficial effects compared with the prior art:

[0017] The reuse rate of the shaft-belt generator of the present invention is increased, and when the main engine does not meet the power generation requirements, it can switch to the reactive power compensation mode; the shaft-belt generator provides reactive power for the ship power grid, avoiding the reactive power impact of the ship load affecting the performance of the generator set; the power factor of the generator set is improved, the output current of the generator set is reduced, the operating efficiency of the generator set is effectively improved, and the fuel consumption of the generator set is reduced; no major hardware changes are required, only a few sets of current sampling CTs need to be added, and the cost performance is high. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 The present invention relates to a shaft-driven generator with a reactive power compensation function;

[0019] Figure 2It is a working schematic diagram of the reactive power compensation mode of the present invention. DETAILED DESCRIPTION

[0020] In order to enable those skilled in the art to better understand the technical solution of the present invention, the present invention is further described below in conjunction with the accompanying drawings and specific implementation methods.

[0021] The present application proposes a shaft-driven generator with reactive power compensation function, comprising: a machine-side rectifier, a grid-side inverter, a shaft-driven controller, and a generator-side sampling CT.

[0022] The AC side of the machine-side rectifier is connected to the shaft-driven motor output, and the DC side is connected to the DC of the grid-side inverter. The machine-side rectifier exchanges data with the shaft generator control system.

[0023] The DC side of the grid-side inverter is connected to the DC side of the machine-side rectifier, and the AC side of the grid-side inverter is connected to the incoming switch of the ship's AC distribution panel, and is connected to the ship's power grid through the AC distribution panel. The grid-side inverter exchanges data with the shaft generator control system.

[0024] The generator-side sampling CT is installed at the output end of the marine generator set, and its secondary side output is sent to the analog input of the shaft generator control system.

[0025] The shaft generator control system exchanges data with the machine-side rectifier and grid-side inverter through communication, and samples the output current and grid voltage of the marine generator set. When the main engine meets the power generation requirements, the shaft generator works in PTO mode, the machine-side rectifier maintains the DC bus voltage, and the grid-side inverter adopts a droop control strategy to output the voltage source and connect to the generator set; when the main engine does not meet the power generation requirements, the machine-side rectifier stops working, and the grid side works in reactive power compensation mode, with the control target of the output power factor of the diesel generator set close to 1.

[0026] Take the shaft-driven generator working in reactive power compensation mode as an example. Figure 2 As shown, when the host does not meet the power generation conditions, the machine-side rectifier stops working, and the grid-side inverter switches to the reactive compensation mode. The output current of the generator set is detected, and the reactive current of the generator set is extracted through coordinate transformation. The sum of the reactive currents of multiple generator sets is used as the outer loop control object of the grid-side inverter control loop, and the control target is that the sum of the reactive currents of the generator sets is 0; the output is the grid-side inverter control inner loop, and the control object of the inner loop control is the grid-side inverter output current, and the output target is that the grid-side inverter output current is 0, and the reactive power is the output of the outer loop control.

[0027] After adopting this control, the power factor of conventional marine loads is 0.8, and the output power factor of the generator set is increased from 0.8 to nearly 1 through the compensation effect of the shaft-belt generator. The generator set only provides active power to the load, and the shaft-belt generator provides reactive power to the load. The advantage of changing the reactive power from being provided by the generator set to being provided by the shaft-belt generator is that the reactive power provided by the generator set is reflected by excitation, which forms the rotor current and the magnetic field through excitation, and then is induced into the stator to maintain the operation of the generator magnetic field. Therefore, the reactive power of the generator includes not only the line loss but also the leakage flux. Therefore, the loss caused by the reactive current in the generator is much higher than the loss taken away by the reactive current from the shaft-belt generator.

[0028] Therefore, when the main engine cannot meet the power generation conditions, the shaft generator starts the reactive power compensation mode, which can reduce the loss caused by reactive current and reduce the fuel consumption of the diesel generator set.

[0029] In summary, the above are only preferred embodiments of the present invention, and the protection scope of the present invention is not limited thereto. All equivalent changes and modifications made according to the patent scope of the present invention and the contents of the specification are within the scope covered by the patent of the present invention.

Claims

1. A shaft-driven generator with reactive power compensation function, characterized in that: include: Machine-side rectifier, grid-side inverter, and shaft generator controller. The AC side of the machine-side rectifier is connected to the shaft motor output, and the DC side of the machine-side rectifier is connected to the DC side of the grid-side inverter. The machine-side rectifier exchanges data with the shaft generator control system.

2. The device according to claim 1, characterized in that: The DC side of the grid-side inverter is connected to the DC side of the machine-side rectifier, and the AC side of the grid-side inverter is connected to the incoming switch of the ship's AC distribution panel, and is connected to the ship's power grid through the AC distribution panel. The grid-side inverter exchanges data with the shaft generator control system.

3. The device according to claim 1, characterized in that: It also includes a generator side sampling CT, which is installed at the output end of the marine generator set, and its secondary side output is sent to the analog input of the shaft generator control system.

4. The device according to claim 1, characterized in that: The shaft generator control system exchanges data with the machine-side rectifier and grid-side inverter through communication, and samples the output current of the marine generator set and the grid voltage at the same time.

5. The device according to claim 1, characterized in that: When the host meets the power generation requirements, the shaft-driven generator operates in PTO mode, the machine-side rectifier maintains the DC bus voltage, and the grid-side inverter adopts a droop control strategy to output the voltage source and connect the generator set to the grid.

6. The device according to claim 1, characterized in that: When the host does not meet the power generation requirements, the machine-side rectifier stops working and the grid-side works in reactive power compensation mode. The control target is to make the output power factor of the diesel generator set close to 1.

7. The device according to claim 6, characterized in that: When the host does not meet the power generation conditions, the machine-side rectifier stops working and the grid-side inverter switches to reactive compensation mode. The output current of the generator set is detected, and the reactive current of the generator set is extracted through coordinate transformation. The sum of the reactive currents of multiple generator sets is used as the outer loop control object of the grid-side inverter control loop, and the control target is to make the sum of the reactive currents of the generator sets zero.

8. The device according to claim 7, characterized in that: The reactive current sum of the generator set is 0, and the output is obtained by the grid-side inverter control inner loop. The control object of the inner loop control is the grid-side inverter output current, and the output target is that the grid-side inverter output current active power is 0, and the reactive power is the output of the outer loop control.

9. The device according to claim 1, characterized in that: After adopting this control, the power factor of conventional marine load is 0.8, and the output power factor of the generator set is increased from 0.8 to close to 1 through the compensation effect of the shaft-driven generator.

10. The device according to claim 9, characterized in that: The generator set only provides active power to the load, and the shaft generator provides reactive power to the load.

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