WO2012142814A1

WO2012142814A1 - Exciting method, device and system of direct-current brushless synchronous wind driven generator

Info

Publication number: WO2012142814A1
Application number: PCT/CN2011/080289
Authority: WO
Inventors: 曹仁贤; 屠运武; 余勇
Original assignee: 阳光电源股份有限公司
Priority date: 2011-04-21
Filing date: 2011-09-28
Publication date: 2012-10-26
Also published as: CN102130644A; CN102130644B

Abstract

An exciting method, device and system of direct-current brushless synchronous wind driven generator. The voltage of a stator winding of a primary generator is rectified to obtain a direct-current output voltage. In combination with the direct-current output voltage, the exciting voltage and the exciting current of an exciter, and rotation speed information of the generator, the system performs inner loop control of the exciting current and performs outer loop control of the direct-current output voltage, and transmits the direct-current exciting voltage to a stator winding of the exciter of the generator by using a method of pulse width modulation. By adjusting the magnitude of the exciting current transmitted to the generator, the output voltage of the generator may be stabilized.

Description

Excitation method, device and system for DC brushless synchronous wind generator The present application claims to be submitted to the Chinese Patent Office on April 21, 2011, the application number is 201110101030.8, and the invention name is "a DC brushless synchronous wind power generator" Priority of Chinese Patent Application for Excitation Method, Apparatus, and System, the entire contents of which are incorporated herein by reference.

TECHNICAL FIELD The present invention relates to the field of wind power generation technologies, and in particular, to an excitation method, device and system for a DC brushless synchronous wind power generator.

Background technique

Generators are the most important equipment in wind power systems. At present, there are basically two types of motors used in wind power generation: asynchronous motors and synchronous motors. There are also two types of fan converters: double-fed and full-power. The asynchronous motor is equipped with a doubly-fed converter, and the synchronous motor is equipped with a full-power converter to form two different wind turbines. For any wind turbine, the implementation of excitation control is critical. Especially for brushless excitation synchronous generators, the brushless excitation system is its core and most critical component.

Usually, when the generator is rotating, it needs a rotating magnetic field (most of the brushless synchronous generator sets are rotating magnetic field type). Most of the magnetic field is formed by the DC power supply through the rotor coil to establish a DC magnetic field. It is the excitation power output part. In addition, in order to keep the voltage of the generator at a constant value when the load changes, a regulator that adjusts the output of the DC power as the voltage at the generator terminal changes is also required. These two aspects are the tasks that the excitation control device has to accomplish.

The stability of the generator output voltage is achieved by controlling the magnitude of the field current. The excitation control of the generator is used to collect changes in the generator voltage and current as well as other input signals, and to control the excitation current supplied to the generator rotor turns according to the control criteria. The excitation control of the generator plays a very important role in maintaining the voltage level of the power system, improving the ability of the power system to operate stably, and improving the operating conditions of the power system and the generator.

Therefore, how to realize the excitation control of the generator, especially for the excitation control of the DC brushless synchronous wind generator, to achieve the stability of the generator output voltage and ensure the stability of the power system is a technology that is urgently needed to be solved by those skilled in the art. problem.

Summary of the invention In view of the above, an object of the present invention is to provide an excitation method, device and system for a DC brushless synchronous wind power generator, which can stabilize the output voltage of the generator by adjusting the magnitude of the excitation current delivered to the generator. Guarantee the stability of the power system.

Embodiments of the present invention provide an excitation method for a DC brushless synchronous wind power generator, wherein an exciter of the DC brushless synchronous wind power generator is coaxially connected with a main generator;

The method includes:

Step 1: Rectify the AC input voltage to obtain a DC input voltage;

Step 2: detecting a three-phase voltage outputted by the stator winding of the main generator, and rectifying the three-phase voltage to obtain a DC output voltage;

Step 3: Detecting the excitation voltage and excitation current of the exciter, the output voltage of any two phases of the stator winding of the main generator, and the current rotational speed of the generator, combined with the DC output voltage obtained by the rectification in the step 2, and the excitation current The inner loop control and the DC output voltage outer loop control obtain a PWM wave; Step 4: according to the PWM wave, invert the DC input voltage obtained in the step 1, and then rectify into a DC excitation voltage, and deliver it to the station. The exciter stator winding of the generator.

Preferably, in step 3, the excitation current inner loop control and the direct current output voltage outer loop control are used to obtain the PWM wave, including:

Step 31: Comparing the given reference voltage with the DC output voltage obtained by the rectification in the step 2, and performing an incremental PI calculation on the comparison result to obtain a first calculation result;

Step 32: setting an adjustment coefficient of the DC output voltage at the current speed according to the current speed of the generator detected in step 3;

Step 33: Multiplying the adjustment coefficient by the first calculation result obtained in step 31 to obtain a excitation current reference value;

Step 34: Comparing the excitation current set value with the excitation current detected in step 3, and performing incremental PI calculation on the comparison result to obtain a required duty cycle value;

Step 35: Generate a PWM wave of a corresponding pulse width according to the duty ratio value.

Preferably, the current speed of the generator is detected in the step 3, including:

Step 301: detecting an output voltage of any two phases of the stator winding of the main generator;

Step 302: Convert the output voltage into a square wave signal that is the same as the output voltage period. Step 303: Acquire a period of the square wave signal to obtain a period of the generator. Step 303: Convert a cycle of the generator into a frequency of the generator, and calculate a current speed of the generator according to a frequency of the generator.

Preferably, the step 4 includes:

Step 41: Invert the DC input voltage obtained in the step 1 according to the PWM wave to obtain an AC voltage.

Step 42: Step-down and rectify the AC voltage obtained by the inverter to obtain a DC excitation voltage, which is sent to the exciter stator winding.

The embodiment of the invention further provides an excitation device for a DC brushless synchronous wind power generator, which is used for a DC brushless synchronous wind power generation system, and the wind power generation system comprises: a DC brushless synchronous wind power coaxial with the main generator and the main generator Generator, and converter;

The converter has a three-phase uncontrolled rectifier circuit, and an input end of the three-phase uncontrolled rectifier circuit is connected to a main generator stator winding for rectifying a three-phase output voltage of the generator, and outputting a DC output voltage to the Exciting device

The excitation device includes: a first rectifier circuit, an excitation power output portion, and a control portion; the first rectifier circuit is configured to, after rectifying the AC input voltage, output a DC input voltage to the excitation power output portion;

The control portion detects an excitation voltage and an excitation current of the exciter, a DC output voltage output by the three-phase uncontrolled rectifier circuit, and an output voltage of any two phases of a stator winding of the main generator, and a generator speed. Outputting a PWM wave to the excitation power output portion through an excitation current inner loop control and a DC output voltage outer loop control, and adjusting an excitation current delivered by the excitation power output portion to the generator;

The excitation power output portion inverts a DC input voltage outputted by the first rectifier circuit according to a PWM wave received from the control portion, and then rectifies the DC excitation current to an exciter stator of the generator Winding.

Preferably, the control part comprises: a controller, a rotation speed detecting circuit, a sampling conditioning circuit, a communication interface circuit, and an auxiliary power supply circuit;

The sampling conditioning circuit is configured to detect the excitation voltage and the excitation current of the exciter, the DC output voltage output by the three-phase uncontrolled rectifier circuit, and the voltage of any two-phase output of the stator winding of the main generator, and output the voltage to the controller ; The rotation speed detecting circuit is configured to detect the rotation speed of the generator and output to the controller; the controller is configured to: according to the received excitation voltage and excitation current of the exciter, the three-phase is not controlled The DC output voltage outputted by the rectifier circuit, and the voltage of any two-phase output of the stator winding of the main generator, and the generator speed are controlled by the inner loop control of the excitation current and the outer loop of the DC output voltage, thereby obtaining the duty ratio required for the output, and generating a PWM wave having a pulse width corresponding to the duty ratio is output to the excitation power output portion;

The communication interface circuit is configured to implement a communication connection between the excitation device and the converter; the auxiliary power supply circuit is configured to be the controller, the pulse control circuit, the communication interface circuit, and the sampling The conditioning circuit provides operating power.

Preferably, the controller includes: a first subtractor, a first PI regulator, an adjustment coefficient calculation unit, a second subtractor, a second PI regulator, and a PWM generator;

a positive input terminal of the first subtractor receives the given reference voltage, a negative input terminal receives a DC output voltage output by the three-phase uncontrolled rectifier circuit via a sampling conditioning circuit, and an output terminal outputs a first comparison result to the First PI regulator;

After the first PI regulator performs incremental PI calculation on the first comparison result, outputting a first calculation result to the adjustment coefficient calculation unit;

The adjustment coefficient calculation unit sets an adjustment coefficient of the DC output voltage at the current rotation speed according to the detected current rotation speed of the generator, and multiplies the first calculation result by the adjustment coefficient And outputting to the positive input terminal of the second subtractor as the excitation current reference value; receiving the excitation current reference value at the positive input end of the second subtractor, and receiving the sampling conditioning voltage detection at the negative input terminal The obtained excitation current, the output terminal outputs a second comparison result to the second PI regulator;

The second PI regulator performs incremental PI calculation on the second comparison result, and outputs a required duty ratio value to the PWM generator;

The PWM generator generates a PWM wave of a corresponding pulse width based on the duty ratio value, and outputs the PWM wave to the excitation power output portion.

Preferably, the controller is a motor control chip dsPIC30F4011.

Preferably, the communication interface circuit comprises: a CAN interface circuit and a serial port interface circuit; the controller is connected to the converter through a CAN interface circuit; The controller is connected to the host computer through a serial port interface circuit.

Preferably, the auxiliary power supply circuit is a single-ended flyback switching power supply composed of a high frequency transformer and a driving chip UC3844.

Preferably, the excitation power output portion comprises: a pulse control circuit, a high frequency pulse transformer, and a second rectifier circuit;

The pulse control circuit is configured to invert a DC input voltage output by the first rectifier circuit according to a PWM wave received from the control portion, and output an inverted AC voltage to the high frequency pulse Transformer

The high frequency pulse transformer is configured to output the voltage to the second rectifying circuit after stepping down the alternating voltage;

The second rectifier circuit is configured to rectify the step-down AC voltage into a DC excitation current, and output the same to the exciter stator winding.

Preferably, the excitation power output part further includes: a filtering and freewheeling circuit;

The filtering and freewheeling circuit is connected to the output end of the second rectifying circuit for filtering the DC excitation current output by the second rectifying circuit and then outputting to the exciter stator winding.

Preferably, the excitation device further comprises: an EMI filter circuit;

The EMI filter circuit is configured to filter the AC input voltage and send it to the first rectifier circuit for rectification.

The embodiment of the invention further provides a coordinated control method for a DC brushless synchronous wind power generation system, wherein the method is used for coordination between the excitation device and a converter of a DC brushless synchronous wind power generation system;

The method includes:

The converter rectifies the three-phase output voltage of the generator, and outputs a DC output voltage to the excitation device; and starts and stops the excitation device according to the rotation speed of the generator, and according to the DC output Voltage is connected to the grid;

The excitation device acts as a slave of the converter, uploading an operating parameter to the converter; the operating parameter includes a rotational speed of the generator; and the excitation device adjusts the delivery to the device according to the rotational speed of the generator The excitation current of the generator is such that the DC output voltage is stabilized.

Preferably, the converter starts and stops the excitation device according to the rotation speed of the generator. System, including:

When the rotation speed of the generator is greater than a preset speed threshold, the converter sends an opening control signal to the excitation device to turn on the excitation device; when the rotation speed of the generator is less than the preset At the speed threshold, the converter sends a shutdown control signal to the excitation device to turn off the excitation current output of the excitation device.

Preferably, the converter performs grid-connecting control according to the DC output voltage, including: when the DC output voltage reaches a preset voltage threshold, the converter sends a grid-connected control signal to the excitation Device.

The embodiment of the present invention further provides a DC brushless synchronous wind power generation system, the system comprising: a DC brushless synchronous wind power generator, a converter, and the excitation device coaxially connected to the main generator and the main generator;

The excitation device provides excitation current for the DC brushless synchronous wind power generator

According to a specific embodiment provided by the present invention, the present invention discloses the following technical effects:

In the embodiment of the present invention, the control part obtains the excitation voltage and the excitation current of the generator, the DC voltage output by the three-phase uncontrolled rectifier circuit, and the output voltage of any two phases of the stator winding of the main generator according to the detection, And a generator speed, using an excitation current inner loop control and a DC voltage outer loop control, outputting a corresponding PWM wave to the excitation power output portion, and adjusting an excitation current outputted by the excitation power output portion to the generator to generate electricity The output voltage of the machine is stable, which improves the stability of the operation of the power system.

The excitation device according to the embodiment of the present invention does not directly track the output voltage of the generator, but is dedicated to stabilizing the DC output of the three-phase voltage output by the generator after being rectified by the three-phase uncontrolled rectifier circuit. The voltage can effectively improve the dynamic quality of the system and provide a reliable guarantee for the inverter to achieve grid-connected operation.

DRAWINGS

In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings to be used in the embodiments will be briefly described below. Obviously, the drawings in the following description are merely the present invention. For some embodiments, other drawings may be obtained from those skilled in the art without departing from the drawings.

1 is a structural view of a DC brushless synchronous wind power generator according to an embodiment of the present invention; 2 is a flow chart of an excitation method of a DC brushless synchronous wind power generator according to an embodiment of the present invention; FIG. 3 is a structural diagram of an excitation device of a DC brushless synchronous wind power generator according to an embodiment of the present invention; Controller structure diagram;

FIG. 5 is a circuit structural diagram of an auxiliary power supply circuit according to an embodiment of the present invention; FIG.

6 is a circuit configuration diagram of a field power output portion according to an embodiment of the present invention;

7a is a circuit structural diagram of a first sampling circuit according to an embodiment of the present invention;

7b is a circuit structural diagram of a second sampling circuit according to an embodiment of the present invention;

7c is a circuit structural diagram of a third sampling circuit according to an embodiment of the present invention;

FIG. 8 is a circuit configuration diagram of a synchronous square wave conversion circuit according to an embodiment of the present invention.

detailed description

The present invention will be further described in detail with reference to the accompanying drawings and specific embodiments.

In view of the above, an object of the present invention is to provide an excitation method, device and system for a DC brushless synchronous wind power generator, which can stabilize the output voltage of the generator by adjusting the magnitude of the excitation current delivered to the generator. Guarantee the stability of the power system.

The excitation method provided by the embodiment of the invention is applied to a DC brushless synchronous wind generator, in particular to a DC brushless synchronous wind generator coaxial with the main generator and the main generator, as shown in FIG.

1 is a structural diagram of a DC brushless synchronous wind power generator according to an embodiment of the present invention. The embodiment of the present invention is described by taking the generator shown in FIG. 1 as an example. The method of the embodiment of the present invention is applicable to a DC brushless synchronous wind generator coaxial with any main generator and the main generator, which may be, but is not limited to, FIG. 1 . The structure shown.

As shown in Fig. 1, the generator 1 includes an exciter 11, a rotary rectifier 12, and a main generator 13. The exciter 11 and the main generator 13 are coaxially connected by the rotary rectifier 12.

Specifically, as shown in FIG. 1, the exciter 11 includes: an exciter stator winding and an exciter rotor armature; and the main generator 13 includes: a main generator rotor armature and a main generator stator winding. The exciter rotor armature and the main generator rotor armature are coaxially connected by the rotary rectifier 12; the exciter stator winding receives a DC excitation voltage.

2 is a flow chart of an excitation method of a DC brushless synchronous wind power generator according to an embodiment of the present invention. As shown in FIG. 2, the method includes the following processes: Step S201: Rectifying the AC input voltage to obtain a DC input voltage.

Step S202: Detecting a three-phase voltage outputted by the stator winding of the main generator, and rectifying the three-phase voltage to obtain a DC output voltage Udc.

It should be noted that the main generator stator winding of the generator 1 outputs U, V, W three-phase voltages, and in step S202, the three-phase voltage is detected, and the three-phase voltage is rectified to obtain a direct current. Output voltage Udc.

Step S203: detecting the excitation voltage Uf and the excitation current If of the exciter 11, the output voltage of any two phases of the stator winding of the main generator, and the current rotation speed n of the generator 1, in combination with the DC output rectified in the step S202. The voltage Udc is controlled by the outer loop control of the excitation current If and the outer loop of the DC output voltage Udc to obtain a duty ratio required for the output, and generate a PWM (Pulse Width Modulation) wave having a pulse width corresponding to the duty ratio. .

It should be noted that, in step S203, the output voltage of any two phases of the stator winding of the main generator is detected, which may be the output line voltage of the U and V phases of the stator winding of the main generator, or may be U, W two-phase output line voltage, or the output line voltage of two phases of V and W.

Step S204: Inverting the DC input voltage obtained in the step S201 according to the PWM wave, and then rectifying into a DC excitation voltage, and transmitting the DC input voltage to the exciter stator winding of the generator.

The working principle of the excitation method in the embodiment of the present invention is:

At a certain wind speed, the fan blade of the synchronous wind turbine 1 drives the main shaft of the generator 1 to rotate through the gearbox. There are two rotor armatures on the main shaft, which are the exciter rotor armature and the main generator rotor armature. . The exciter rotor armature is coupled to the main generator rotor armature via the rotary rectifier 12. The excitation method according to the embodiment of the present invention detects the two-phase terminal voltage of the main generator 13 and the rotational speed of the main generator 13, and simultaneously detects the three-phase output voltage of the rectified main generator stator winding, and excites according to the characteristics of the motor. The stator winding is input with the corresponding DC excitation current If. When the rotational speed of the generator 1 reaches a certain value, the three-phase voltage rectified DC output voltage Udc outputted by the main generator stator winding is stabilized. By adjusting the duty ratio of the PWM wave, the on/off of the switching tube is controlled, and the exciting current If of the stator winding of the exciter delivered to the generator is adjusted.

Since the stator winding of the exciter is a large inductive load, the excitation current If forms an directional magnetic field on the stator winding of the exciter. When the exciter rotor armature rotates with the fan blade, a set of three-phase alternating current is generated in the exciter rotor armature, and the three-phase alternating current is fixed on the generator main shaft. After the rectifier rectifier 12 is rectified, a direct current is outputted to the main generator rotor armature, thereby establishing a rotating magnetic field in the main generator 13. At this time, the coil of the stator winding of the main generator starts to cut the magnetic field line of the rotating magnetic field, and according to the law of electromagnetic induction, an alternating voltage output is generated in the stator winding of the main generator, and finally the fan generates electricity, and the output three-phase voltage After being rectified, the DC output voltage Udc is obtained, and the outer loop control of the DC output voltage Udc is realized, so that the DC output voltage Udc is stable and controllable.

Preferably, the current speed n of the generator 1 detected in step S203 can be specifically as follows: Step S203-1: The output voltage of any two phases of the stator winding of the main generator is detected.

Step S203-2: Converting the output voltage into a square wave signal having the same period as the output voltage.

Step S203-3: Acquire a period of the square wave signal to obtain a period of the generator.

Since the period of the square wave signal is the same as the period of the output line voltage of any two phases of the stator winding of the main generator, thereby obtaining the period of the square wave signal, the period of the generator can be obtained.

Step S203-4: Converting the period of the generator into a frequency of the generator, and calculating the current rotation speed of the generator according to the frequency of the generator.

Obtaining the frequency of the generator according to the cycle of the generator, and then calculating the rotational speed of the generator, is a very mature technology in the field and will not be described in detail here. The DC output voltage is controlled by the Udc outer loop to obtain the duty cycle required for the output, and the specific process of generating the PWM wave corresponding to the duty cycle is described in detail. The process may include: Step 203-11: Comparing a given reference voltage Ug with the DC output voltage Udc obtained by the rectification in the step 202, and performing an incremental PI calculation on the comparison result to obtain a first calculation result.

The determination of the given reference voltage Ug can be achieved by the above steps:

First, a given reference voltage initial value UgO is set in advance, and the given reference voltage initial value UgO is compared with the DC output voltage Udc obtained in step 202 to obtain a difference AU, and the difference AU is determined. Whether it is within a preset difference range, and if so, the given reference voltage initial value UgO is taken as the given reference voltage Ug; if not, a value is taken within the preset difference range As the current difference Δ U ' , the sum of the DC output voltage Udc and the current difference Δ U′ (ie, Udc+AU′) is taken as the given reference voltage Ug. For example, when the preset difference range is 0~40V, the current difference Δ ΙΓ may be selected to be 40V. Of course, the preset difference range may be specifically set according to actual needs.

Step 203-12: Set the adjustment coefficient of the DC output voltage Udc at the current rotation speed according to the current rotation speed of the generator 1 detected in the step 203.

Specifically, the rotation speed n of the generator 1 can be divided into sections, and the adjustment coefficient of the corresponding DC output voltage Udc is set for each section of the rotation speed. For example, the speed n can be divided into five zones, and the corresponding adjustment coefficient of each zone is Ki (i=l, 2, 3, 4, 5), as follows:

When n<1200rmp/min, set the adjustment factor to K1;

When 1200rmp/min<n<1400rmp/min, set the adjustment factor to K2;

When 1400rmp/min <n<1600rmp/min, set the adjustment factor to K3;

When 1600rmp/min<n<1800rmp/min, set the adjustment factor to K4;

When 1800rmp/min<n<2000rmp/min, set the adjustment factor to K5.

In the step 203-12, according to the interval in which the current rotational speed of the generator 1 is located, the adjustment coefficient of the DC output voltage Udc corresponding to the current rotational speed can be determined.

Step 203-13: Multiply the adjustment coefficient by the first calculation result obtained in step 203-11, and obtain the product as the excitation current reference value Ig.

Step 203-14: The excitation current set value Ig is compared with the excitation current If detected in step 203, and the comparison result is subjected to incremental PI calculation to obtain a required duty ratio value.

Step 203-15: Generate a PWM wave of a corresponding pulse width according to the duty ratio value.

The switching of the switching tube is controlled by the PWM wave, thereby adjusting the magnitude of the current in the stator winding of the input generator 1, and stabilizing the output voltage of the stator winding of the main generator.

In the embodiment of the present invention, the excitation voltage Uf and the excitation current If of the exciter 11 , the three-phase voltage rectified DC output voltage Udc output by the generator 1 , and any two phases of the stator winding of the main generator are obtained according to the detection. The output voltage, and the generator speed, using the excitation current If inner loop control and the DC output voltage Udc outer loop control, output corresponding PWM waves, and adjust the excitation current delivered to the generator 1, so that the output voltage of the generator 1 Stable, improve the stability of power system operation.

The method according to the embodiment of the present invention does not directly track the output voltage of the generator 1, but is dedicated to stabilizing the DC output voltage Udc of the three-phase voltage outputted by the generator 1 after being rectified, which can be effective. Improve the dynamic quality of the system and provide reliable guarantee for the converter to achieve inverter connection and grid work. Preferably, in the method of the embodiment of the present invention, in step S201, before the rectifying the AC input voltage, the method further includes: performing a step-down process on the AC input voltage.

Further, in step S201, before the rectifying the AC input voltage, the method further includes: performing EMI (electromagnetic interference) filtering on the AC input voltage.

Of course, in the embodiment of the present invention, the AC input voltage may be stepped down, and then the stepped AC input voltage is EMI filtered, and then the filtered voltage is rectified.

In the following step S204 of the method of the present invention, the DC input voltage obtained in the step S201 is inverted according to the PWM wave, and then rectified into a DC excitation voltage, and sent to the exciter of the generator. The specific process of the stator winding is described in detail. The process can include:

Step 204-1: Inverting the DC input voltage obtained in the step 201 according to the PWM wave to obtain an AC voltage;

Step 204-2: Step-down and rectify the AC voltage obtained by the inverter to obtain a DC excitation voltage, which is sent to the exciter stator winding. Corresponding to the excitation method of the DC brushless synchronous wind power generator provided by the embodiment of the invention, the embodiment of the invention further provides an excitation device for the DC brushless synchronous wind power generator. 3 is a structural diagram of an excitation device of a DC brushless synchronous wind power generator according to an embodiment of the present invention.

It should be noted that the excitation device provided by the embodiment of the present invention is applied to a DC brushless synchronous wind power generation system, and particularly to a wind power generation system of a DC brushless synchronous wind power generator having an exciter coaxial with a main generator.

Specifically, in the embodiment of the present invention, the wind power generation system shown in FIG. 1 is still taken as an example for description. The wind power generation system may include: a DC brushless synchronous wind power generator 1, and a current transformer 3. The exciter of the generator 1 is coaxially connected to the main generator.

The structure of the generator 1 shown in Fig. 3 is the same as that shown in Fig. 1, and will not be described again.

It should be noted that the converter 3 has a three-phase uncontrolled rectifier circuit 32, and the input end of the three-phase uncontrolled rectifier circuit 32 is connected to the main generator stator winding of the generator 1, and receives the generator.

After the three-phase output voltages of 1, V, and W are rectified, the DC output voltage Udc is outputted to the excitation device 2. The exciter stator winding of the generator 1 receives the excitation output of the exciter 2 as a load of the excitation device 2.

As shown in FIG. 3, the excitation device 2 according to the embodiment of the present invention may include: a first rectifier circuit 23, an excitation power output portion, and a control portion.

The first rectifier circuit 23 is configured to output a DC input voltage to the excitation power output portion after rectifying the AC input voltage.

It should be noted that the AC input voltage may be provided by an operating power supply (shown as 21 in FIG. 1), and the AC input voltage outputted by the operating power supply 21 is rectified by the first rectifying circuit 23, and the DC input voltage is output. To the excitation power output portion.

The control portion detects the excitation voltage Uf and the excitation current If of the exciter 11, the DC output voltage Udc output by the three-phase uncontrolled rectifier circuit 32, and the output voltages of any two phases of the stator winding of the main generator, And the generator speed is controlled by the excitation current If inner loop control and the DC output voltage Udc outer loop, outputting a PWM wave to the excitation power output portion, and adjusting the excitation current output portion to the excitation current of the generator 1 The output voltage of the generator 1 is stabilized, and the stability of the operation of the power system is improved.

The excitation power output portion inverts the DC input voltage output from the first rectifying circuit 23 based on the PWM pulse received from the control portion, and then rectifies the DC input current into a DC exciting current, and outputs it to the exciter stator winding.

Specifically, as shown in FIG. 3, the control portion may include: a controller 28, a rotation speed detecting circuit 30, a sampling conditioning circuit 31, a communication interface circuit 33, and an auxiliary power supply circuit 27.

The controller 28 is a core of the control part, and can be implemented by using a DSP (Digital Signal Processing) processor.

The sampling conditioning voltage 31 is configured to detect the excitation voltage Uf and the excitation current If of the exciter 11, the DC output voltage Udc output by the three-phase uncontrolled rectifier circuit 32, and the voltage of any two phases of the stator winding of the main generator. Output to the controller 28.

It should be noted that, in FIG. 3, the voltage of any two-phase output of the stator winding of the main generator detected by the sampling conditioning voltage 31 is described by taking the line voltage Uac of two phases of V and W as an example. Of course, in other embodiments of the present invention, it is also possible to detect a line voltage of two phases of 11, V or a line voltage of two phases of 11, W. The rotation speed detecting circuit 30 is configured to detect the rotation speed of the generator 1 and output it to the controller 28.

The controller 28 is configured to: according to the received excitation voltage Uf and excitation current If of the exciter 11, the DC output voltage Udc output by the three-phase uncontrolled rectifier circuit 32, and any two of the stator windings of the main generator The output voltage of the phase and the generator speed are controlled by the inner loop control of the excitation current If and the outer loop of the DC output voltage Udc to obtain the required duty ratio of the output, and generate a PWM corresponding to the duty ratio of the duty cycle (Pulse Width) Modulation, pulse width modulation) Wave, output to the excitation power output section.

The communication interface circuit 33 is configured to implement a communication connection between the excitation device 2 and the converter 3 of the wind power generator.

It should be noted that the communication interface circuit 33 may be composed of a CAN (Controller Area Network) interface circuit and a serial interface circuit portion. The controller 28 and the converter 3 are connected by a CAN interface circuit, and communicated by using a CAN bus to coordinate the operation of the excitation device; the controller 28 is connected to the host computer through a serial port interface circuit to realize communication, For program maintenance. The upper computer is used to control the working state of the excitation system of the entire DC brushless synchronous wind power generator.

The auxiliary power supply circuit 27 is configured to provide operating power for the controller 28, the pulse control circuit 24, the communication interface circuit 33, and the sampling conditioning circuit 31.

It should be noted that, when the controller 28 is a DSP processor, the rotation speed detecting circuit 30 can be realized by a synchronous square wave converting circuit.

Specifically, the synchronous square wave converting circuit receives the line voltage of any two-phase output of the stator winding of the main generator detected by the sampling conditioning voltage 31, and converts the line voltage into a square wave signal with the same line voltage period. Input to the capture port of the DSP processor. The DSP processor acquires a period of the square wave signal according to the captured square wave signal; and the power generation can be obtained because the square wave signal has the same period as the line voltage of any two phases of the stator winding of the main generator The cycle of the machine is converted to the frequency of the generator and, in turn, converted to the speed of the generator. The specific implementation of the synchronous square wave conversion circuit will be described in detail later.

Preferably, the control portion may further include: a digital input and output circuit 29.

The digital input and output circuit 29 terminates the converter 3 and the other end is connected to the controller 28. When changing When the flow device 3 detects an external abnormality, and the communication between the converter 3 and the excitation device is interrupted, the converter 3 can transmit a shutdown control signal to the digital input/output circuit 29; when the external abnormality is eliminated, The converter 3 sends an open control signal to the digital input and output circuit 29.

The switch input/output circuit 29 is configured to directly turn off the excitation current output of the excitation device by the controller 28 when receiving the shutdown control signal; and turn on the excitation by the controller 28 when receiving the turn-on control signal Device.

As shown in FIG. 3, the excitation power output portion may include: a pulse control circuit 24, a high frequency pulse transformer 25, and a second rectifier circuit 26.

The pulse control circuit 24 is configured to invert the DC input voltage output by the first rectifier circuit 23 according to the PWM pulse received from the control portion, and output the inverted AC voltage to the high Frequency pulse transformer 25.

The high frequency pulse transformer 25 is configured to output the voltage to the second rectifier circuit 26 after stepping down the AC voltage.

The second rectifier circuit 26 rectifies the stepped AC voltage into a DC excitation current and outputs the resultant to the exciter stator winding.

The working principle of the excitation device 2 of the DC brushless synchronous wind power generator according to the embodiment of the present invention is:

At a certain wind speed, the fan blade of the synchronous wind turbine 1 drives the main shaft of the generator 1 to rotate through the gearbox. There are two rotor armatures on the main shaft, which are the exciter rotor armature and the main generator rotor armature. . The exciter rotor armature is coupled to the main generator rotor armature through the rotary rectifier 12. The excitation device 2 detects the terminal voltage of any two phases of the main generator 13 (in the present embodiment, the terminal voltage Uac of the two phases of V and W is taken as an example), and the main generator 13 is detected by the capture port of the controller 28. Frequency, and calculate the rotational speed of the main generator 13 by using the relationship between the rotational speed of the motor and the pole logarithm and frequency, and simultaneously detect the DC output voltage Udc outputted by the three-phase uncontrolled rectifier circuit 32, and give the exciter stator according to the characteristics of the motor. The winding inputs the corresponding DC excitation current If. When the rotational speed of the generator reaches a certain value, the DC output voltage Udc outputted by the three-phase uncontrolled rectifier circuit 32 is stabilized. The duty cycle adjustable PWM wave is controlled by the controller 28, thereby controlling the switching of the switching transistor in the pulse control circuit 24, thereby realizing controllable energy of the input high frequency pulse transformer 25, which is then passed through the high frequency pulse transformer 25. The energy is reduced to an appropriate voltage level and output to the exciter stator winding of the generator 1, Thereby, the excitation current If is adjustable.

Since the stator winding of the exciter is a large inductive load, the pulse output from the high-frequency transformer 25 can be converted into a direct current to realize DC excitation. This DC current If forms a directional magnetic field on the stator windings of the exciter. When the exciter rotor armature rotates with the fan blade propeller, a set of three-phase alternating current is generated in the exciter rotor armature, and the three-phase alternating current is rectified by the rotary rectifier 12 fixed on the generator main shaft, and then output. The direct current is supplied to the main generator rotor armature, thereby establishing a rotating magnetic field in the main generator 13. At this time, the coil of the stator winding of the main generator starts to cut the magnetic field line of the rotating magnetic field. According to the law of electromagnetic induction, an alternating voltage output is generated in the stator winding of the main generator, and finally the fan generates electricity, and the three-phase electric power is generated. The three-phase uncontrolled rectifier circuit 32 is rectified and detected by the excitation device 2 to realize outer loop control of the DC output voltage Udc, so that the DC output voltage Udc outputted by the three-phase uncontrolled rectifier circuit 32 is stable and controllable.

Referring to FIG. 4, it is a structural diagram of a controller according to an embodiment of the present invention. The controller 28 includes: a first subtractor 283, a first PI (proportional integral) regulator 284, an adjustment coefficient calculation unit 282, a second subtractor 285, a second PI regulator 286, and a PWM generator 287.

The positive input terminal of the first subtractor 283 receives the given reference voltage Ug, and the negative input terminal thereof receives the DC output voltage Udc output by the three-phase uncontrolled rectifier circuit 32 via the sampling conditioning circuit 31, and the output thereof The terminal outputs a first comparison result to the first PI regulator 284.

The first PI regulator 284 performs an incremental PI calculation on the first comparison result, and outputs a first calculation result to the adjustment coefficient calculation unit 282.

The adjustment coefficient calculation unit 282 sets an adjustment coefficient of the DC output voltage Udc at the current rotation speed according to the detected current rotation speed of the generator 1, and receives the first adjustment from the first PI regulator 284. The product of the calculation result and the adjustment coefficient is output as the excitation current reference value Ig to the positive input terminal of the second subtractor 285.

Specifically, the rotation speed n of the generator 1 is divided into sections, and the adjustment coefficient of the corresponding DC output voltage Udc is set for each section of the rotation speed. For example, the rotational speed n can be divided into five intervals, and the corresponding adjustment coefficients for each interval are Ki (i=l, 2, 3, 4, 5), as follows:

When n<1200rmp/min, set the adjustment factor to K1;

When 1200rmp/min<n<1400rmp/min, set the adjustment factor to K2;

When 1400rmp/min <n<1600rmp/min, set the adjustment factor to K3; When 1600rmp/min<n<1800rmp/min, set the adjustment factor to K4;

When 1800rmp/min<n<2000rmp/min, set the adjustment factor to K5.

The adjustment coefficient calculation unit 282 determines an adjustment coefficient of the DC output voltage Udc corresponding to the current rotation speed according to the detected interval of the current rotation speed of the generator 1, and receives the adjustment coefficient from the first PI regulator 284. A calculation result is multiplied by the adjustment coefficient, and the obtained product is output as the excitation current reference value Ig to the positive input terminal of the second subtractor 285.

The positive input terminal of the second subtractor 285 receives the excitation current reference value Ig output by the adjustment coefficient calculation unit 282, and the negative input terminal receives the excitation current If detected by the sampling conditioning voltage 31, and outputs the output end thereof. The second comparison result is to the second PI regulator 286.

The second PI regulator 286 performs an incremental PI calculation on the second comparison result, and outputs a required duty value to the PWM generator 287.

The PWM generator 287 generates a PWM wave of a corresponding pulse width according to the duty ratio value, and outputs it to the excitation power output portion.

The on/off of the MOSFET switch tube in the pulse control circuit 24 is controlled by the PWM wave, thereby adjusting the magnitude of the current in the stator winding of the exciter of the input generator 1, and stabilizing the output voltage of the stator winding of the main generator.

In the embodiment of the present invention, the control portion obtains the excitation voltage Uf and the excitation current If of the exciter 11 , the DC output voltage Udc output by the three-phase uncontrolled rectifier circuit 32, and the stator winding of the main generator according to the detection. The output voltage of the two phases and the generator speed are controlled by the excitation current If inner loop control and the DC output voltage Udc outer loop, and output corresponding PWM waves to the excitation power output portion, and adjust the excitation power output portion to be delivered to the The excitation current of the generator 1 stabilizes the output voltage of the generator 1 and improves the stability of the operation of the power system.

The excitation device according to the embodiment of the present invention does not directly track the output voltage of the generator 1, but is dedicated to stabilizing the three-phase voltage output by the generator 1 after being rectified by the three-phase uncontrolled rectifier circuit 32. The output DC output voltage Udc can effectively improve the dynamic quality of the system and provide a reliable guarantee for the converter to achieve grid-connected operation.

It should be noted that, in the embodiment of the present invention, the controller 28 can be implemented by using a DSP chip dsPIC30F4011 in the field of motor and motion control. The excitation device can fully utilize the rich resources of the DSP chip and combine with DSP software programming to easily implement various control algorithms and A variety of communication methods improve the reliability and response real-time performance of the excitation device. The DSP chip dsPIC30F4011 can directly specify the duty value required for the output through the register, thereby realizing a fast and reliable wide-range output of the excitation current, so as to adapt to the wind generator to output a stable DC output voltage Udc even when the wind speed changes rapidly. .

Preferably, the excitation device of this embodiment may further include: an AC transformer 22. The alternating current transformer 22 is connected between the working power supply 21 and the first rectifying circuit 23, and the alternating current input voltage outputted by the working power supply 21 is converted to a predetermined voltage level by the alternating current transformer 22, and then input to the The first rectifier circuit 23 performs rectification.

Preferably, the excitation device of the embodiment may further include: an EMI (Electromagnetic Interference) filter circuit 34. The EMI filter circuit 34 may be connected between the AC voltage converter 22 and the first rectifier circuit 23, and configured to filter the AC input voltage after the AC voltage converter 22 is transformed, and then send the The first rectifier circuit 23 performs rectification.

Of course, in the embodiment of the present invention, the EMI filter circuit may be further included, and the EMI filter circuit may be directly connected between the working power source 21 and the first rectifier circuit 23 for filtering the AC input voltage and then sending the signal to the AC input voltage. The first rectifier circuit 23 performs rectification.

In the embodiment of the present invention, the auxiliary power supply circuit 27 is configured to provide working power for the controller 28, the pulse control circuit 24, the communication interface circuit 33, and the sampling conditioning circuit 31.

In an actual application, the auxiliary power supply circuit 27 can be a separate power supply, and each of the circuits is provided with a required operating power; the auxiliary power supply circuit 27 can also utilize the DC voltage output by the first rectifier circuit 23, The conversion is provided to each circuit to provide the required working power, so that the excitation power output portion of the excitation device and the power supply of the control portion are both provided by the same working power source 21, saving power.

Referring to FIG. 5, it is a circuit structural diagram of an auxiliary power supply circuit according to an embodiment of the present invention. The auxiliary power supply circuit 27 is a single-ended flyback switching power supply using a high frequency transformer and a driver chip UC3844.

As shown in Figure 5, the high frequency transformer has a plurality of secondary windings, one for each secondary winding.

An input end of the primary winding of the transformer is connected to an output end of the first rectifying circuit 23, and an AC input voltage outputted by the working power supply 21 is converted and rectified by a voltage level of the AC transformer 22 and the first rectifying circuit 23. After that, the output DC input voltage is applied to the transformer at the beginning of the switching power supply. The drive chip UC3844 controls the on and off of the switch tube Q1 to transfer energy to the secondary winding of the transformer of the switching power supply.

When the switch tube Q1 is turned on, the primary winding of the transformer absorbs energy from the output end of the first rectifier circuit 23; when the switch tube Q1 is turned off, the transformer converts electrical energy into magnetic energy and transmits it to the switch. The secondary windings of the transformer of the power supply.

The output of the first secondary winding W1 of the transformer is regulated by the chip U7805CV, and the DC+5V voltage is output to supply power to the controller 28.

The outputs of the second secondary winding W2 and the third secondary winding W3 of the transformer are respectively regulated by the chips U7815CV and U7915CV, and output DC+15V and DC-15V voltages, and the sampling conditioning circuit 31 is supplied with power to ensure the output. The voltage to the controller 28 is stabilized.

The fourth secondary winding W4, the fifth secondary winding W5 and the sixth secondary winding W6 of the transformer output three independent +20V voltages which are not common, as the switching transistor driving chip of the pulse control circuit 24 Working power supply.

In the embodiment of the present invention, the auxiliary power supply circuit 27 shown in FIG. 5 is used, so that the excitation power output portion of the excitation device and the power supply of the control portion are both provided by the same working power source 21, and the design of the switching power supply circuit is Each circuit module of the control section is powered. Compared with the DC-DC power supply which respectively sets the corresponding specifications for each circuit module, the design cost, the tubular circuit structure, and the requirement for the use environment can be greatly saved, so that the integration of the excitation device is higher.

In the embodiment of the present invention, the switching power supply allows a wide variation range of the input voltage, so that the output of the excitation device is widely adjustable, so that the brushless synchronous wind generator still has a large range of wind speed variation. It is capable of outputting a stable DC output voltage Udc.

Referring to FIG. 6, a circuit configuration diagram of a field power output portion according to an embodiment of the present invention is shown. As can be seen from Fig. 3, the excitation power output portion includes: a pulse control circuit 24, a high frequency pulse transformer 25, and a second rectifier circuit 26.

The high frequency pulse transformer 25 is configured to output the voltage to the second rectifier circuit 26 after stepping down the AC voltage. The second rectifier circuit 26 rectifies the stepped AC voltage into a DC excitation current and outputs the same to the exciter stator winding.

Referring to FIG. 6, the pulse control circuit 24 may include a signal driving circuit 241, a second MOS transistor Q2, a third MOS transistor Q3, a fourth MOS transistor Q4, and a fifth MOS transistor Q5.

The input end of the signal driving circuit 241 is connected to the PWM pulse signal outputted by the controller 28. The output end of the signal driving circuit 241 is connected to the gate of the second MOS transistor Q2 and the gate of the third MOS transistor Q3. The gate of the fourth MOS transistor Q4 and the gate of the fifth MOS transistor Q5.

The drain of the second MOS transistor Q2 and the drain of the fourth MOS transistor Q4 are short-circuited, and are connected to the first output end of the first rectifier circuit 23.

The source of the second MOS transistor Q2 is connected to the drain of the third MOS transistor Q3, and its common terminal is connected to the first end of the primary winding of the high frequency pulse transformer 25.

The source of the fourth MOS transistor Q4 is connected to the drain of the fifth MOS transistor Q5, and the common terminal thereof is connected to the second end of the primary winding of the high frequency pulse transformer 25.

The drain of the third MOS transistor Q3 and the drain of the fifth MOS transistor Q5 are short-circuited to be connected to the second output terminal of the first rectifier circuit 23.

As shown in FIG. 6, the second rectifier circuit 26 of the embodiment of the present invention may be a rectifier bridge composed of four diodes. Specifically, the second rectifier circuit 26 may include: a first diode D1, a second diode D2, a third diode D3, and a fourth diode D4.

The cathode of the first diode D1 is connected to the anode of the second diode D2; the cathode of the second diode D2 is connected to the anode of the third diode D3; The cathode of the diode D3 is connected to the anode of the fourth diode D4; the cathode of the fourth diode D4 is connected to the anode of the first diode D1.

a common end of the first diode D1 and the second diode D2 is connected to a first end of the secondary winding of the high frequency pulse transformer 25; the third diode D3 and the fourth diode D4 The common terminal terminates the second end of the secondary winding of the high frequency pulse transformer 25.

The common end of the first diode D1 and the fourth diode D4 serves as a positive output end of the pulse control circuit, and is also a positive output end of the excitation device (shown as Idc+ in FIG. 6); The common terminal of the second diode D2 and the third diode D3 serves as a negative output terminal of the pulse control circuit, and is also a negative output terminal of the excitation device (shown as Idc- in FIG. 6). Preferably, the excitation power output portion may further include: a filtering and freewheeling circuit 35, the filtering and freewheeling circuit 35 is connected to an output end of the second rectifying circuit 26, and configured to be used for the second rectifying circuit The output DC excitation voltage is filtered, and then output to the exciter stator winding as the excitation output of the excitation device.

The filtering and freewheeling circuit 35 can be a RC absorption circuit. Specifically, the filtering and freewheeling circuit 35 may include: a first resistor R1, a first capacitor Cl, and a fifth diode D5. The first resistor R1 is connected in series with the first capacitor C1, and is coupled between the positive output terminal and the negative output terminal of the pulse control circuit; the cathode of the fifth diode D5 is connected to the cathode The positive output of the pulse control circuit, the anode of the fifth diode D5 is connected to the negative output of the pulse control circuit.

The working principle of the excitation power output portion will be explained below with reference to FIG. 6:

The DC input voltage output from the first rectifier circuit 23 is input to the pulse control circuit 24. The pulse control circuit 24 is composed of a signal driving circuit 241 and a switching transistor. The controller 28 controls a PWM wave of a certain duty ratio, and the signal driving circuit 241 controls the switching of the switching tube.

It should be noted that the third switching transistor, the third MOS transistor Q3 and the fifth MOS transistor Q5, which are the lower arms of the pulse control circuit 24, are always in a high conduction state when the PWM pulse signal is not received. This can function to freewheel the primary winding of the high frequency pulse transformer 25.

The PWM wave outputted by the controller 28 is a center symmetric complementary type with a fixed dead zone, so that the up and down through of the same bridge arm of the pulse control circuit 24 can be avoided.

The energy outputted by the switching tube of the pulse control circuit 24 is converted by the high frequency pulse transformer 25, and then output to the exciter via the second rectifying circuit 26, the filtering and freewheeling circuit 35, and the reverse fast recovery diode. Stator winding. The exciter stator winding is a large inductive load, and the output pulse amount of the high-frequency pulse transformer 25 can be filtered into a direct current as long as the period of the PWM wave outputted by the controller 28 is much smaller than the time constant of the load. Thereby achieving DC excitation of the synchronous generator.

The sampling conditioning circuit 31 of the embodiment of the invention is configured to detect the excitation voltage Uf and the excitation current If of the exciter 11, the DC output voltage Udc output by the three-phase uncontrolled rectifier circuit 32, and any two phases of the stator winding of the main generator. The output voltage is output to the controller 28 after the respective signals are detected and processed accordingly.

The sampling conditioning circuit 31 includes: a first sampling circuit, a second sampling circuit, and a third sampling circuit. Referring to FIG. 7a to FIG. 7c, respectively, a first sampling circuit and a second sampling power according to an embodiment of the present invention Circuit, and circuit diagram of the third sampling circuit.

The first sampling circuit is configured to detect an output voltage between any two phases of the stator winding of the main generator, and correspondingly process the voltage, and output the signal to the controller 28.

As shown in FIG. 7a, the first sampling circuit in the embodiment of the present invention may include:

One end of the second resistor R2 and one end of the third resistor R3 are respectively connected to any one of the stator windings of the main generator, and the other end of the second resistor R2 and the other end of the third resistor R3 are connected. The input of a Hall voltage sensor.

The output end of the first Hall voltage sensor is connected to one end of the fourth resistor R4, and the other end of the fourth resistor R4 is connected to a fixed end of the adjustable resistor W1.

The fifth resistor R5, the sixth resistor R6, and the second capacitor C2 are all connected in parallel between the output of the first Hall voltage sensor and the ground.

The other fixed end of the adjustable resistor W1 is grounded via a seventh resistor R7, and the sliding end of the adjustable resistor W1 is connected to the positive input terminal of the first voltage follower U1 via an eighth resistor R8.

The output end of the first voltage follower U1 is connected to one end of the ninth resistor R9, and the negative input end of the first voltage follower U1 is short-circuited with the output end thereof; the positive input end of the first voltage follower U1 is The third capacitor C3 is grounded.

The other end of the ninth resistor R9 is connected to one end of the tenth resistor R10 and one end of the eleventh resistor R11; the other end of the tenth resistor R10 is connected to the working power source Vrer; the other end of the eleventh resistor R11 One end of the fourth capacitor C4 and one input of the controller 28 are connected.

The other end of the fourth capacitor C4 is grounded.

As shown in FIG. 7a, the output voltage of any two phases of the stator winding of the main generator (in FIG. 7a, only the voltage Uac of the two phases of U and V is taken as an example) is divided by the second resistor R2 and the third resistor R3. And inputting the first Hall voltage sensor; the first Hall voltage sensor converts the received strong electric signal into a weak electric signal, and simultaneously acts as a strong electric and weak electric isolation; and passes through the first Hall voltage The signal after the sensor conversion passes through the voltage division of the adjustable resistor W1, the fourth resistor R4, and the seventh resistor R7, and the RC filter (the fifth resistor R5, the sixth resistor R6, and the second capacitor C2), the first A voltage follower U1, and a subsequent voltage boost circuit, are finally input to the controller 28. The controller 28 has a 10-bit AD converter built therein, and samples the received signal. The sampling frequency can be set by the controller 28. The highest sampling frequency can reach 1 MHz, which satisfies the requirements of sampling accuracy and speed. The real-time nature of control provides the necessary protection.

The voltage boosting circuit is composed of a ninth resistor R9, a tenth resistor R10, and an eleventh resistor R11, and is used for converting the signal outputted by the first voltage follower U1 to between 0 and 5V to avoid a negative voltage.

The second sampling circuit is configured to detect the DC output voltage Udc outputted by the three-phase uncontrolled rectifier circuit 32, and perform corresponding processing on the DC output voltage Udc, and output the signal to the controller 28.

As shown in FIG. 7b, the second sampling circuit in the embodiment of the present invention may include:

One end of the twelfth resistor R12 and one end of the thirteenth resistor R13 are respectively connected to the positive output terminal and the negative output terminal of the three-phase uncontrolled rectifier circuit 32, and the other end of the twelfth resistor R12 and the tenth The other end of the three resistor R13 is connected to the input of the second Hall voltage sensor.

The output of the second Hall voltage sensor is connected to the positive input terminal of the second voltage follower U2 via the fourteenth resistor R14.

The output end of the second voltage follower U2 is connected to one end of the fifteenth resistor R15, the negative input end of the second voltage follower U2 is shorted to the output end thereof; the positive input end of the second voltage follower U2 Grounded via the fifth capacitor C5.

The other end of the fifteenth resistor R15 is connected to one end of the sixth capacitor C6 and an input terminal of the controller 28.

The other end of the sixth capacitor C6 is grounded.

The principle of the second sampling circuit is similar to that of the first sampling circuit, except that the second sampling circuit has no voltage raising circuit, and details are not described herein.

The third sampling circuit is configured to detect the excitation voltage Uf and the excitation current If of the exciter 11, and process the excitation voltage Uf and the excitation current If, and output the same to the controller 28.

As shown in FIG. 7c, the third sampling circuit in the embodiment of the present invention may include:

The current sensor is connected in series with the positive input end of the exciter stator winding, and the output end of the current sensor is connected to one end of the sixteenth resistor R16 and one end of the eighth capacitor C8.

The other end of the sixteenth resistor R16 is connected to one end of the seventh capacitor C7 and an input terminal of the controller 28.

The other end of the seventh capacitor C7 is grounded; the other end of the eighth capacitor C8 is grounded. One end of the seventeenth resistor R17 is connected to the negative input end of the exciter stator winding, and one end of the nineteenth resistor R19 is connected to the positive input end of the exciter stator winding.

The other end of the seventeenth resistor R17 is connected to an input end of the third voltage sensor U3 via the eighteenth resistor R18, and the other end of the nineteenth resistor R19 is connected to the third voltage sensor via the twentieth resistor R20. Another input to U3.

The output end of the third voltage sensor U3 is connected to one end of the twenty-first resistor R21 and an input terminal of the controller 28.

The other end of the twenty-first resistor R21 is grounded.

It should be noted that the voltage sensor in the third sampling circuit can adopt a Hall current type voltage sensor, and the seventh resistor R17, the eighteenth resistor R18, the nineteenth resistor R19, and the twentieth resistor R20 through the resistor. The voltage to be measured (ie the voltage across the stator windings of the exciter) is converted into a current to increase the immunity to interference. Then, it is converted into a small current signal by the Hall current type voltage sensor, and finally converted into a voltage signal by the twenty-first resistor R21, and input to the AD converter inside the controller 28 for sampling. Wherein, the current sensor for detecting the excitation current If can use a non-contact Hall current sensor to achieve the isolation effect.

In the embodiment of the present invention, when the rotation speed detecting circuit 30 is realized by a synchronous square wave converting circuit, the synchronous square wave converting circuit can be as shown in FIG. 8.

FIG. 8 is a circuit configuration diagram of a synchronous square wave conversion circuit according to an embodiment of the present invention. The synchronous square wave conversion circuit 30 may include:

One end of the twenty-second resistor R22 and one end of the twenty-third resistor R23 are respectively connected to any one of the stator windings of the main generator, the other end of the twenty-second resistor R22 and the twenty-third resistor The other end of R23 is connected to the input of the fourth Hall voltage sensor.

The output of the fourth Hall voltage sensor is connected to the negative input terminal of the zero comparator U3 via the twenty-fourth resistor R24.

The positive input terminal of the zero-crossing comparator U3 is grounded; the ninth capacitor C9 is connected to the zero-crossing comparator

Between the positive input and the negative input of U3.

The output end of the zero-crossing comparator U3 is connected to one end of the twenty-fifth resistor R25, and the other end of the twenty-fifth resistor R25 is connected to one end of the twenty-sixth resistor R26, the anode of the sixth diode D6, The cathode of the seventh Zener diode D7. The other end of the twenty-sixth resistor R26 is connected to the +5V working power supply; the anode of the seventh Zener diode D7 is connected to one end of the twenty-seventh resistor R27.

The other end of the twenty-seventh resistor R27 is connected to the cathode of the sixth diode D6, and is commonly connected to an input terminal of the controller 28.

The synchronous square wave converting circuit 30 receives the line voltage of any two-phase output of the stator winding of the main generator detected by the sampling conditioning circuit 31, and the line voltage is input to the fourth Hall voltage sensor after being divided by the resistor. Signal conversion is performed, and the converted signal is input to the zero-crossing comparator U3. Such a sine wave signal is converted into a square wave signal having the same period as the line voltage after passing through the zero-crossing comparator U3 and the subsequent voltage limiting circuit. Input to the capture port of the controller 28, with the software to complete the acquisition of the motor frequency and speed. Corresponding to the excitation device of the DC brushless synchronous wind power generator provided by the embodiment of the present invention, the embodiment further provides a coordinated control method for the DC brushless synchronous wind power generation system, wherein the DC brushless synchronous wind power generation system includes: excitation A DC brushless synchronous wind turbine, a converter, and an excitation device coaxial with the main generator.

The method is used to achieve coordinated work between the excitation device and the converter. The excitation device is the same as the excitation device described in the foregoing embodiments of the present invention, and will not be described again.

The converter communicates with a controller of the excitation device through the communication interface circuit. The coordinated control method includes:

The three-phase uncontrolled rectifier circuit of the converter rectifies the three-phase output voltage of the generator, and outputs a DC output voltage Udc to the excitation device.

The excitation device acts as a slave of the converter, uploading operating parameters to the converter.

It should be noted that the operating parameters include a frequency and a rotational speed of the generator, a terminal voltage of the generator, an excitation current and an excitation voltage, a duty ratio of the PWM wave, and the like.

The excitation device adjusts an excitation current delivered to the generator according to a rotational speed of the generator such that the DC output voltage Udc is stabilized.

The converter performs start-stop control of the excitation device according to the rotational speed of the generator, and performs grid-connected control according to the DC output voltage Udc.

Specifically, when the converter detects that the speed of the generator is greater than a preset speed threshold, Dissolving an opening control signal to the excitation device, the excitation device is turned on by the controller; and when the current transformer detects that the rotation speed of the generator is less than the preset speed threshold, the shutdown is performed The control signal is sent to the excitation device, and the excitation current output of the excitation device is directly turned off by the controller to stop the operation of the generator.

Preferably, the preset speed threshold may be specifically set according to actual needs. For example, it can be set to 480rmp/min.

The converter receives the DC output voltage Udc uploaded by the excitation device, and when the DC output voltage Udc reaches a certain voltage threshold, sends a grid connection control signal to the excitation device.

The certain voltage threshold can be specifically set according to actual needs. For example, if it is set to 1040V, the grid-connected operation is performed when the DC output voltage Ud reaches 1040V.

After performing the grid-connected operation, during the power generation of the generator, the converter is responsible for adjusting the power factor of the generator and other requirements required for the stability of the power system, and inverting the DC output voltage Udc to meet The AC voltage required by the network. Corresponding to the excitation device of the DC brushless synchronous wind power generator provided by the embodiment of the present invention, the present embodiment further provides a DC brushless synchronous wind power generation system. The system includes a DC brushless synchronous wind generator, a converter, and an excitation device.

The exciter of the DC brushless synchronous wind power generator is coaxially connected with the main generator. The converter has a three-phase uncontrolled rectifier circuit, and an input end of the three-phase uncontrolled rectifier circuit is connected to a stator winding of a main generator for rectifying a three-phase output voltage of the generator, and outputting a DC output voltage to the Excitation device.

The excitation device provides an excitation current for the DC brushless synchronous wind power generator. The excitation device is the same as the excitation device described in the foregoing embodiments of the present invention, and will not be described again.

In the embodiment of the present invention, the control part obtains the excitation voltage and the excitation current of the generator, the DC voltage output by the three-phase uncontrolled rectifier circuit, and the output voltage of any two phases of the stator winding of the main generator according to the detection, And a generator speed, using an excitation current inner loop control and a DC voltage outer loop control, outputting a corresponding PWM wave to the excitation power output portion, and adjusting an excitation current outputted by the excitation power output portion to the generator to generate electricity The output voltage of the machine is stable, which improves the stability of the operation of the power system. The excitation device and system according to the embodiment of the present invention do not directly track the output voltage of the generator, but are dedicated to stabilizing the output of the three-phase voltage of the generator through the three-phase uncontrolled rectifier circuit. The DC voltage can effectively improve the dynamic quality of the system and provide a reliable guarantee for the inverter to achieve grid-connected operation.

The above description of the excitation method, device and the like of the DC brushless synchronous wind power generator provided by the present invention are only used to help understand the method and core idea of the present invention; The person skilled in the art will have a change in the specific embodiment and application range according to the idea of the present invention. In conclusion, the contents of this specification are not to be construed as limiting the invention.

Claims

Rights request

A method for exciting a DC brushless synchronous wind power generator, characterized in that: an exciter of the DC brushless synchronous wind power generator is coaxially connected with a main generator;

The method includes:

Step 1: Rectify the AC input voltage to obtain a DC input voltage;

2. The method according to claim 1, wherein in step 3, the excitation current is controlled by an inner loop of the excitation current and the outer loop of the direct current output voltage, and the PWM wave is obtained, including:

3. The method according to claim 1, wherein the detecting the current rotational speed of the generator in the step 3 comprises:

Step 302: Convert the output voltage into a square wave signal that is the same as the output voltage period. Step 303: Acquire a period of the square wave signal to obtain a period of the generator.

Step 303: Convert the cycle of the generator to the frequency of the generator, according to the generator Frequency, the current speed of the generator is calculated.

The method according to claim 1, wherein the step 4 includes: Step 41: Inverting the DC input voltage obtained in the step 1 according to the PWM wave to obtain an AC voltage;

5 . An excitation device for a DC brushless synchronous wind power generator, used for a DC brushless synchronous wind power generation system, characterized in that: the wind power generation system comprises: a DC brushless synchronous wind power coaxial with an excitation machine and a main generator Generator, and converter;

The excitation device of the DC brushless synchronous wind power generator according to claim 5, wherein the control portion comprises: a controller, a rotation speed detecting circuit, a sampling conditioning circuit, a communication interface circuit, and an auxiliary power supply circuit;

7. The excitation device of a DC brushless synchronous wind power generator according to claim 6, wherein the controller comprises: a first subtractor, a first PI regulator, an adjustment coefficient calculation unit, and a second subtractor. , second PI regulator, PWM generator;

8. The excitation device of a DC brushless synchronous wind power generator according to claim 7, wherein the controller is a motor control chip dsPIC30F4011.

9. The excitation device of a DC brushless synchronous wind power generator according to claim 6, wherein the communication interface circuit comprises: a CAN interface circuit and a serial port interface circuit;

The controller is connected to the converter through a CAN interface circuit;

The controller is connected to the host computer through a serial port interface circuit.

The excitation device for a DC brushless synchronous wind power generator according to claim 6, wherein the auxiliary power supply circuit is a single-ended flyback switching power supply composed of a high frequency transformer and a driving chip UC3844.

The excitation device for a DC brushless synchronous wind power generator according to claim 5, wherein the excitation power output portion comprises: a pulse control circuit, a high frequency pulse transformer, and a second rectification circuit;

The excitation device of the DC brushless synchronous wind power generator according to claim 11, wherein the excitation power output portion further comprises: a filtering and freewheeling circuit;

13. The excitation device of a DC brushless synchronous wind power generator according to claim 12, wherein the excitation device further comprises: an EMI filter circuit;

A coordinated control method for a DC brushless synchronous wind power generation system, characterized in that the method is applied to the excitation device according to any one of claims 5 to 13 and the current transformer of a DC brushless synchronous wind power generation system Coordination between work;

The method includes: The converter rectifies the three-phase output voltage of the generator, and outputs a DC output voltage to the excitation device; and starts and stops the excitation device according to the rotation speed of the generator, and according to the DC output Voltage is connected to the grid;

The method according to claim 14, wherein the converter performs start-stop control of the excitation device according to the rotational speed of the generator, and includes:

The method according to claim 14, wherein the converter performs grid-connected control according to the DC output voltage, including:

When the DC output voltage reaches a preset voltage threshold, the converter sends a grid-connected control signal to the excitation device.

17. A DC brushless synchronous wind power generation system, the system comprising: a DC brushless synchronous wind power generator, a converter, and a claim 5 to 13 in which an exciter is coaxially connected to a main generator An excitation device according to any of the preceding claims;

The excitation device provides an excitation current for the DC brushless synchronous wind power generator.