CN201440646U - A structure of excitation control system for marine diesel engine brushless doubly-fed shaft generator - Google Patents

Abstract

The utility model relates to a structure for an excitation control system of a brushless double-fed shaft generator for a marine diesel engine disclosed. , DC compensation unit, inverter unit, operation panel, excitation controller, AB phase voltage sensor, CA phase voltage sensor, BC phase voltage sensor; based on the control method of the control system structure, the marine brushless double-fed shaft belt power generation can be realized Machine excitation, constant voltage control, constant frequency control, undervoltage protection and overvoltage protection.

Description

A structure of excitation control system for marine diesel engine brushless doubly-fed shaft generator

technical field

The utility model belongs to the technical field of generator automatic control, in particular to a control system structure for a marine diesel engine brushless double-fed shaft generator.

Background technique

At present, separate diesel generator sets are widely used on ships to generate electricity, which consumes a large amount of light diesel oil every year. If the main engine of the ship can be fully utilized for shaft power generation, energy and costs can be greatly saved. However, the speed of the ship's main engine changes frequently during navigation, which requires the generator and control system to be capable of variable speed, voltage stabilization, and constant frequency power generation. How to solve the technical problem of shaft power generation by the main engine of the ship, technicians in the field have proposed various solutions, but with little success. The fundamental reason is that the marine diesel brushless double-fed shaft generator is a kind of The structure of the shaft generator of the marine diesel engine that uses heavy oil as fuel, the structure of the brushless doubly-fed motor should be different from the traditional structure theoretically. There are two sets of three-phase windings on the stator: the power winding and the control winding. The output of the power winding is used as the main power output of the brushless doubly-fed generator to supply power to the ship. The purpose of the control winding is to establish and regulate the field current. When the diesel engine speed and the electrical load of the generator change, in order to maintain the stability of the output voltage and frequency of the generator, the current of the control winding must be adjusted in real time.

Regarding the above-mentioned background technology, in the published patent documents, the inventor of the utility model has not retrieved any content related to the control system of the marine diesel shaft brushless doubly-fed generator.

Contents of the invention

The purpose of this utility model is to provide an excitation control system structure for a brushless double-fed shaft generator of a marine diesel engine, so that the brushless double-fed shaft generator of a marine diesel engine can Realize self-excited power generation and have the ability to stabilize voltage and constant frequency, adopt bias frequency control strategy near the natural synchronous speed point in the operation of brushless double-fed generators to make the generator load characteristics smooth transition and have a certain load capacity. This new control system makes the brushless doubly-fed shaft generator for marine diesel engine have high operation efficiency, energy saving, good stability and high reliability.

In order to achieve the purpose of the utility model, the utility model proposes the following technical scheme of the marine brushless doubly-fed shaft generator control system structure: an excitation control system structure for the marine diesel engine brushless doubly-fed shaft generator The marine brushless doubly-fed shaft generator excitation control system is structurally connected between the power winding, control winding, rotary encoder, ship power station, and ship 220V battery pack of a brushless doubly-fed shaft generator, and is characterized in that: The structure of the marine brushless double-fed shaft generator excitation control system consists of a contactor, a step-up transformer, a rectification feedback unit, a DC compensation unit, an inverter unit, an operation panel, an excitation controller, an AB phase voltage sensor, a CA phase It is composed of voltage sensor and BC phase voltage sensor.

The input end of the contactor is connected to the three-phase power winding of the shaft generator, the output end of the contactor is connected to the ship power station; the input end of the step-up transformer is connected to the three-phase power winding of the shaft generator, and the step-up transformer The output end of the rectification feedback unit is connected to the AC input end of the rectification feedback unit; the rectification feedback unit is connected to the DC input end of the inverter unit; the input end of the DC compensation unit is connected to the DC 220V battery pack, and the output end of the DC compensation unit is connected to the inverter unit The DC input terminal is connected; the three-phase AC output terminal of the inverter unit is connected to the control winding of the shaft generator; the input terminal of the excitation controller is connected to the operation panel, AB phase voltage sensor, CA phase voltage sensor, BC phase voltage sensor, shaft Rotary encoder with generator, the output end of excitation controller is connected with contactor, DC compensation unit and inverter unit.

The step-up transformer, rectification feedback unit, DC compensation unit and inverter unit of the utility model provide excitation current for the generator control winding, the generator power winding is connected to the AC end of the rectification feedback unit through a three-phase step-up transformer, and the rectification feedback unit The DC terminal, the output terminal of the DC compensation unit and the DC terminal of the inverter unit are connected to the DC bus, the 220V battery pack on board is connected to the input terminal of the DC compensation unit, and the AC output terminal of the inverter unit is connected to the shaft brushless On the control winding of the doubly-fed generator.

The rotary encoder of the utility model is directly connected with the generator shaft, and its signal output end is connected to the excitation controller, and the voltage Hall sensor detects the output voltage of the power winding of the generator, and its signal output end is connected to the excitation controller. The operation panel is connected with the excitation controller to provide operation instructions.

The above step-up transformer and rectification feedback unit of the utility model keep the DC bus voltage within the range where the inverter unit can work normally. When the output voltage of the generator is low, the step-up transformer can increase the DC bus voltage. High, the energy is fed back to the DC bus, and when the DC bus voltage increases, the rectification feedback unit can feed back the DC bus energy to the output terminal of the generator, so that the DC bus voltage remains stable.

The inverter unit of the utility model inverts the direct current on the direct current bus into three-phase alternating current to supply the control winding of the generator, and the voltage amplitude, frequency and phase sequence of the three-phase alternating current change according to the control instruction signal of the excitation controller.

The input end of the above-mentioned DC compensation unit of the utility model is a DC 220V battery pack on the ship, and the output end is connected to the DC bus. When the generator is excited, the DC compensation unit provides the energy required for excitation; when the generator is working normally, the capacitor energy storage module in the DC compensation unit is used to compensate for the instantaneous drop of the DC bus voltage.

According to the feedback signal of the rotary encoder and the voltage Hall sensor, the above-mentioned excitation controller of the utility model controls the output voltage amplitude, frequency and phase sequence of the contactor, the DC compensation unit, and the inverter unit, so as to achieve different rotational speeds of the ship diesel engine. Excitation and constant frequency voltage regulation control of brushless doubly-fed shaft generator under varying load conditions.

The superiority and technical effect of the utility model are: to provide a control system structure for the marine diesel engine shaft brushless double-fed generator, so that the marine diesel engine shaft brushless double-fed generator can change the shaft speed of the ship's main diesel engine. Under working conditions, it can realize self-excitation power generation and has the ability of constant voltage and constant frequency. The bias frequency control strategy is adopted near the commutation speed point in the operation of the brushless doubly-fed generator to make the generator load characteristics transition smoothly and have a certain load. ability. The new structure and method of the control system make the marine diesel shaft brushless double-fed generator have high operation efficiency, energy saving, good stability and high reliability.

Description of drawings:

Fig. 1 is the overall structural representation of the utility model

Figure 2 is a schematic diagram of the structure of the excitation controller

Figure 3 is a schematic diagram of the structure of the DC compensation unit

Detailed ways

Below in conjunction with accompanying drawing, the utility model is described in further detail.

In Fig. 1, the marine brushless double-fed shaft generator excitation control system structure 1 is connected to the power winding 15, control winding 16, rotary encoder 17, ship power station 12, ship Between 13 220V battery packs. Its characteristics are: the marine brushless double-fed shaft generator excitation control system structure 1 includes contactor 2, step-up transformer 3, rectification feedback unit 4, DC compensation unit 5, inverter unit 6, operation panel 7, excitation control 8, AB phase voltage sensor 9, CA phase voltage sensor 10, BC phase voltage sensor 11. in:

The input end of the contactor 2 is connected to the three-phase power winding 15 of the shaft generator 14, the output end of the contactor 2 is connected to the ship power station 12; the input end of the step-up transformer 3 is connected to the three-phase power winding 15 of the shaft generator 14 15 connected, the output end of the step-up transformer 3 is connected to the AC input end of the rectification feedback unit 4; the rectification feedback unit 4 is connected to the DC input end of the inverter unit 6; the input end of the DC compensation unit 5 is connected to the DC 220V battery pack 13 , the output terminal of the DC compensation unit 5 is connected to the DC input terminal of the inverter unit 6; the three-phase AC output terminal of the inverter unit 6 is connected to the control winding 16 of the shaft generator 14; the input terminal of the excitation controller 8 is connected to operate Panel 7, AB phase voltage sensor 9, CA phase voltage sensor 10, BC phase voltage sensor 11, rotary encoder 17 of shaft generator 16, the output end of excitation controller 8 is connected to contactor 2, DC compensation unit 5 and inverter Change unit 6.

The function of contactor 2 is to ensure that the power winding 15 of the shaft generator 14 is disconnected from the ship power station 12 during the excitation process. Only when the excitation process is completed and the output voltage of the power winding 15 of the shaft generator 14 is stable, can the The contactor 2 is closed, and the shaft generator 14 supplies power to the marine power station 12 .

The function of the step-up transformer 3 is to increase the input voltage of the rectification feedback unit 4 while maintaining the output voltage of the power winding 15 of the shaft generator 14 at a rated voltage of 400V, which is conducive to maintaining the stability of the DC bus voltage. The step-up transformer 3 can be realized in the form of an autotransformer.

The function of the rectification feedback unit 4 is to realize the bidirectional flow of electric energy between the power winding 15 of the shaft generator 14 and the DC bus. The rectification and feedback unit can rectify the three-phase alternating current into direct current and supply it to the DC bus, and then provide it to the control winding 16 of the shaft generator 14 through the inverter unit 6. When the control winding 16 also generates power externally, the rectification and feedback unit 4 works in the feedback mode, the electric energy generated by the control winding 16 is fed back to the three-phase output end of the power winding 15 through the inverter unit 6 , the rectification feedback unit 4 , and the step-up transformer 3 .

The function of the DC compensation unit 5 is to provide excitation power for the shaft generator 15 and ensure the stability of the DC bus during operation.

The function of the inverter unit 6 is to invert the DC bus voltage into a three-phase AC voltage with adjustable amplitude, frequency and phase sequence and output it to the three-phase control winding 16 of the shaft generator 14 .

The function of the operation panel 7 is to provide the start and stop signals of the excitation control system 1 of the shaft generator, and the excitation controller 8 realizes relevant control after receiving the signals.

The function of the excitation controller 8 is to realize excitation, constant voltage and constant frequency control of the shaft generator 14 by controlling the contactor 2 , the DC compensation unit 5 and the inverter unit 6 .

The function of the three voltage sensors 9, 10, 11 is to provide the excitation controller 8 with the instantaneous measured value of the output voltage of the shaft generator 14, and the sensors can be in the form of Hall sensors.

In Fig. 2, the excitation controller 8 is connected to the operation panel 7, the AB phase voltage sensor 9, the CA phase voltage sensor 10, the BC phase voltage sensor 11, the encoder 17, the contactor 2, the DC compensation unit 5 and the inverter unit 6 between. The characteristic is that the excitation controller 8 includes an excitation control module 81 , a constant voltage control module 82 and a constant frequency control module 83 . in:

The input end of the excitation control module 81 is connected to the output end of the operation panel 7, and the output end of the excitation control module 81 is connected to the input ends of the contactor 2, the DC compensation unit 5, the constant voltage control module 82, and the constant frequency control module 83 The output end of AB phase voltage sensor 9, CA phase voltage sensor 10, BC phase voltage sensor 11 is connected with the input end of constant voltage control module 82; The output end of encoder 17 is connected with the input end of constant frequency control module 83; The output terminals of the voltage control module 82 and the constant frequency control module 83 are connected to the input terminals of the inverter unit 6 .

The role of the excitation control module 81 is to realize the excitation process of the shaft generator 14. After receiving the start signal from the operation panel, the excitation control module 81 first disconnects the contactor 2, and at the same time controls the DC compensation unit to be the DC bus Charging, and then through the constant voltage control module 82 and the constant frequency control module 83, control the inverter unit 6 to gradually increase the excitation voltage, so that the output voltage of the power winding 15 of the shaft generator 14 reaches a stable 400V, and at this time the excitation control module 81 By closing the contactor 2 , the shaft generator 14 can supply power to the marine power station 12 . During the excitation process, the output voltage of the DC compensation unit 5 is higher than the output voltage of the rectification feedback unit 4, and the excitation energy comes from the DC 220V battery 13. After the excitation process is completed, the output voltage of the rectification feedback unit 4 is higher than that of the DC compensation unit 5, the DC compensation unit 5 no longer outputs current, and the excitation energy comes from the power winding 15 of the shaft generator 14 .

The function of the constant voltage control module 82 is to ensure that the output voltage of the power winding 15 of the shaft generator 14 is stable at a rated value of 400V, and the instantaneous fluctuation is less than plus or minus 10%. The constant voltage control module adjusts the output voltage amplitude of the inverter unit 6 by comparing the difference between the measured values of the three-phase voltage sensors 9, 10, 11 and the rated 400V, so as to keep the output voltage of the power winding 15 stable.

The function of the constant frequency control module 83 is to ensure that the output frequency of the power winding 15 of the shaft generator 14 is stable at a rated value of 50 Hz, and the frequency deviation is less than 0.1 Hz. The constant frequency control module adjusts the output voltage frequency of the inverter unit 6 to keep the output frequency of the power winding 15 stable by comparing the difference between the actual speed of the shaft generator 14 detected by the encoder 17 and the speed of the natural synchronous point.

In FIG. 3 , the DC compensation unit 5 is connected between the DC 220V battery 13 , the rectification feedback unit 4 , the inverter unit 6 and the excitation controller 8 . The characteristic is that the DC compensation unit 5 includes a step-up chopper power supply 51 , a capacitor energy storage module 52 and a charging control module 53 . in:

The input end of the boost chopper power supply 51 is connected to the output end of the DC 220V storage battery 13; the input end of the capacitor energy storage module 52 is connected to the output end of the boost chopper power supply 51; the input end of the charging control module 53 is connected to the capacitor energy storage The output terminal of the module 52 is connected with the output terminal of the excitation controller 8 ; the output terminal of the charging control module 53 is connected with the output terminal of the rectification feedback unit 4 and the input terminal of the inverter unit 6 .

The effect of the step-up chopper power supply 51 is to boost the 220V direct current of the battery pack 13 to a direct current above 400V that can directly supply the inverter unit 6 to work. The capacitor energy storage module provides peak power for the DC bus. When the output voltage of the power winding 15 of the shaft generator 14 drops, the DC bus voltage will drop. The capacitor energy storage module can quickly provide energy for the DC bus and maintain the DC bus voltage. Stablize. The function of the charging control module is to avoid the instantaneous large current caused by direct charging of the capacitor inside the inverter unit 6 when the shaft generator 14 is excited.

Claims (1)

1. An excitation control system structure for a brushless doubly-fed shaft generator of a marine diesel engine, which is connected to the power winding, control winding, rotary encoder, ship power station, and ship 220V of a brushless doubly-fed shaft generator Between the battery packs, it is characterized in that: the structure of the marine brushless doubly-fed shaft generator excitation control system consists of a contactor, a step-up transformer, a rectification feedback unit, a DC compensation unit, an inverter unit, an operation panel, and an excitation control unit. The input end of the contactor is connected with the three-phase power winding of the shaft generator, and the output end of the contactor is connected with the ship power station; the step-up transformer The input end is connected to the three-phase power winding of the shaft generator, the output end of the step-up transformer is connected to the AC input end of the rectification feedback unit; the rectification feedback unit is connected to the DC input end of the inverter unit; the input end of the DC compensation unit is connected to the The DC 220V battery pack is connected, the output terminal of the DC compensation unit is connected to the DC input terminal of the inverter unit; the three-phase AC output terminal of the inverter unit is connected to the control winding of the shaft generator; the input terminal of the excitation controller is connected to the operation panel , AB phase voltage sensor, CA phase voltage sensor, BC phase voltage sensor, rotary encoder of the shaft generator, the output end of the excitation controller is connected to the contactor, the DC compensation unit and the inverter unit.