A variable pitch drive and method of controlling the same

Abstract

The application provides a variable pitch driver and a control method thereof. Since the pre-charging process of each stage only includes one charging path, if it is judged that the voltage between the two ends of the DC side capacitor branch arranged on the DC side of the rectifier circuit does not reach the set value corresponding to the stage during the pre-charging process of the stage, it can be detected that the switch tube in the charging path corresponding to the stage cannot work normally; since the pre-charging process of the DC side capacitor branch is divided into at least two stages and is carried out one by one during the soft start process of the variable pitch driver, and the charging paths corresponding to all stages cover all switch tubes, it can be detected whether each switch tube in the variable pitch driver cannot work normally; since all the above-mentioned switch tubes are current type devices, the variable pitch driver whose own switch tube is a current type device can detect whether each switch tube in itself cannot work normally during the soft start process of itself.

Description

Technical Field

[0001] This invention relates to the field of automatic control technology, and in particular to a pitch drive and its control method. Background Technology

[0002] Currently, the pitch control system is a very important electrical component of wind turbine generator sets, and the pitch drive is the core component of the pitch system. The pitch drive drives the pitch motor to operate by receiving position commands from the master controller in real time, thereby realizing real-time adjustment of the blade angle, which in turn ensures the stability and reliability of wind turbine power generation, and maximizes the utilization of wind resources.

[0003] Typically, pre-charging of the DC-side capacitor in the rectifier circuit of the pitch driver is achieved by gradually increasing the voltage across the capacitor. Since the switching transistors in the rectifier circuit are current-type devices such as thyristors, the pre-charging of the DC-side capacitor can be achieved by gradually increasing the voltage across the capacitor by changing the conduction angle, thus realizing the soft start of the pitch driver. However, during its own soft start process, the pitch driver cannot detect whether each of its switching transistors is malfunctioning, which may lead to the pitch driver operating with a single phase, resulting in large fluctuations in the DC-side voltage of the pitch driver. This, in turn, causes torque pulsation in the pitch motor, meaning the pitch motor cannot operate stably and may even affect the normal discharge of the wind turbine.

[0004] Therefore, how to enable a pitch driver with current-type switching transistors to detect whether each of its switching transistors is malfunctioning during its soft-start process is a technical problem that urgently needs to be solved. Summary of the Invention

[0005] In view of this, the present invention provides a pitch driver and its control method, so that a pitch driver whose own switching transistors are current-type devices can detect whether each of its switching transistors is malfunctioning during its soft-start process.

[0006] To achieve the above objectives, the embodiments of the present invention provide the following technical solutions:

[0007] This application provides a control method for a pitch driver, wherein the rectifier circuit in the pitch driver adopts a full-bridge rectifier topology, all switches in the rectifier circuit are current-type devices, and a DC-side capacitor branch is provided on the DC side of the rectifier circuit; the control method includes:

[0008] During the soft start process of the pitch driver, the pre-charging process of the DC side capacitor branch is divided into at least two stages and carried out one by one; each stage of the pre-charging process includes only one charging path, and the charging paths corresponding to the pre-charging processes of all stages cover all the switching transistors.

[0009] During the pre-charging process at each stage, it is determined whether the voltage across the DC-side capacitor branch reaches the set value corresponding to the pre-charging process at this stage.

[0010] If the voltage across the DC-side capacitor branch does not reach the set value corresponding to the pre-charging process in this stage, then the pre-charging process in this stage is determined to be abnormal.

[0011] Optionally, after determining that an anomaly has occurred during the pre-charging process in this stage, the following steps are also included:

[0012] Perform the protection steps for the pitch drive.

[0013] Optionally, performing the protection steps of the pitch drive includes:

[0014] Control the pitch drive to stop.

[0015] Optionally, if the voltage across the DC-side capacitor branch reaches the set value corresponding to the pre-charging process in this stage, it is determined that the pre-charging process in this stage has not been abnormal, and the soft-start process of the pitch driver continues.

[0016] Optional, also includes:

[0017] During the operation of the pitch driver, if the voltage fluctuation amplitude at both ends of the DC-side capacitor branch exceeds a preset amplitude range, and / or the voltage fluctuation frequency at both ends of the DC-side capacitor branch exceeds a preset frequency range, then the rectifier circuit is determined to be malfunctioning.

[0018] Optionally, after determining that the rectifier circuit has malfunctioned, the method further includes:

[0019] Perform the protection steps for the pitch drive.

[0020] This application also provides a pitch driver, comprising: a rectifier circuit, a DC-side capacitor branch, a controller, and at least two voltage sampling circuits; wherein:

[0021] The AC side of the rectifier circuit is connected to an AC power source, and the DC side of the rectifier circuit is connected to the power supply terminal of the pitch motor.

[0022] The two ends of the DC-side capacitor branch are respectively connected to the two poles of the DC side of the rectifier circuit;

[0023] All of the voltage sampling circuits are connected to the controller. One voltage sampling circuit is used to sample the DC side voltage of the rectifier circuit, and the remaining voltage sampling circuits are used to sample the voltage between every two connection terminals on the AC side of the rectifier circuit.

[0024] The rectifier circuit is controlled by the controller, which is used to perform the control method as described in any of the preceding aspects of this application.

[0025] Optionally, the rectifier circuit adopts a three-phase rectifier topology or a single-phase rectifier topology.

[0026] Optionally, in each bridge arm of the rectifier circuit, the upper half of the bridge arm is a switching transistor and the lower half of the bridge arm is a diode, and the cathode of the diode in the lower half of the bridge arm is connected to the output terminal of the switching transistor in the upper half of the bridge arm.

[0027] or,

[0028] In each bridge arm of the rectifier circuit, the upper half of the bridge arm is a switching transistor, and the lower half of the bridge arm is a switching transistor. The output terminal of the switching transistor in the upper half of the bridge arm is connected to the input terminal of the switching transistor in the lower half of the bridge arm.

[0029] Optionally, the switching transistor in the pitch driver is a thyristor.

[0030] Optionally, each of the voltage sampling circuits employs a differential sampling topology.

[0031] Optionally, it also includes: an inverter circuit; wherein:

[0032] The DC side of the rectifier circuit is connected to the DC side of the inverter circuit, and the AC side of the inverter circuit is connected to the power supply terminal of the pitch motor.

[0033] The inverter circuit is controlled by the controller.

[0034] Optionally, it may also include: a DC / DC conversion circuit; wherein:

[0035] The DC side of the rectifier circuit is connected to the first side of the DC / DC converter circuit, and the second side of the DC / DC converter circuit is connected to the power supply terminal of the pitch motor.

[0036] The DC / DC conversion circuit is controlled by the controller.

[0037] As can be seen from the above technical solution, the present invention provides a control method for a pitch drive. Since each stage of the pre-charging process includes only one charging path, if, during a certain stage of the pre-charging process, it is determined that the voltage across the DC-side capacitor branch on the DC side of the rectifier circuit has not reached the set value corresponding to this stage of the pre-charging process, then the switching transistor in the charging path corresponding to this stage of the pre-charging process can be detected as not functioning properly. Furthermore, since the pre-charging process of the DC-side capacitor branch is divided into at least two stages during the soft-start process of the pitch drive, and the charging paths corresponding to all stages of the pre-charging process cover all switching transistors, this method can detect whether each switching transistor in the pitch drive is not functioning properly. In addition, since all the aforementioned switching transistors are current-type devices, this control method enables a pitch drive whose own switching transistors are current-type devices to detect whether each of its own switching transistors is not functioning properly during its own soft-start process. Attached Figure Description

[0038] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on the provided drawings without creative effort.

[0039] Figures 1-6 The following are flowcharts illustrating six implementations of the control method for the pitch drive provided in this application.

[0040] Figures 7-10 These are schematic diagrams illustrating four implementations of the pitch drive provided in this application. Detailed Implementation

[0041] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of this application.

[0042] In this application, relational terms such as "first" and "second" are used merely to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitation, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes said element.

[0043] In order to enable a pitch driver whose own switching transistors are current-type devices to detect whether its own switching transistors are not working properly during its soft start-up process, this application provides a control method for a pitch driver. The rectifier circuit in the pitch driver adopts a full-bridge rectifier topology, and all the switching transistors in the rectifier circuit are current-type devices. A DC-side capacitor branch is provided on the DC side of the rectifier circuit.

[0044] Optionally, the current-source device can be a thyristor, such as Figures 7-10 As shown, in practical applications, including but not limited to this, no specific limitation is made here, and it can be determined according to the specific circumstances, all of which are within the protection scope of this application.

[0045] Optionally, the above rectifier circuit can adopt a single-phase rectifier topology, such as... Figure 7 or Figure 8 As shown; a three-phase rectifier topology can also be used, such as Figure 9 or Figure 10 As shown; no specific limitation is made here, which may be determined depending on the specific circumstances, and all are within the scope of protection of this application.

[0046] Optionally, in each bridge arm of the rectifier circuit, the upper half of the bridge arm can be a switching transistor and the lower half of the bridge arm can be a diode; or the upper half of the bridge arm can be a switching transistor and the lower half of the bridge arm can be a switching transistor. No specific limitation is made here, and it can be determined according to the specific situation. All of these are within the protection scope of this application.

[0047] The specific flow of the control method for the pitch drive is as follows: Figure 1 As shown, the specific steps include:

[0048] S110. During the soft start process of the pitch driver, the pre-charging process of the DC side capacitor branch is divided into at least two stages and carried out one by one.

[0049] For example, suppose that during the soft start process of the pitch drive, the voltage across the DC-side capacitor branch needs to be charged from 0V to 100V, and the pre-charging process of the DC-side capacitor branch is divided into two stages. In the first stage of pre-charging, the voltage across the DC-side capacitor branch is charged from 0V to 50V, and in the second stage of pre-charging, the voltage across the DC-side capacitor branch is charged from 50V to 100V.

[0050] For example, suppose that during the soft start process of the pitch drive, the voltage across the DC-side capacitor branch needs to be charged from 0V to 100V, and the pre-charging process of the DC-side capacitor branch is divided into two stages. In the first stage of pre-charging, the voltage across the DC-side capacitor branch is charged from 0V to 60V, and in the second stage of pre-charging, the voltage across the DC-side capacitor branch is charged from 60V to 100V.

[0051] Each stage of the pre-charging process includes only one charging path, and the charging paths corresponding to the power conversion of all stages cover all the switching transistors in the rectifier circuit.

[0052] For example, such as Figure 7 As shown, the rectifier circuit adopts a single-phase full-bridge rectifier topology, and in each bridge arm of the rectifier circuit, the upper half of the bridge arm is a switching transistor and the lower half of the bridge arm is a diode. The above pre-charging process includes two stages. The charging path corresponding to the pre-charging process in one stage is T1 and D2, and the charging path corresponding to the pre-charging process in the other stage is T2 and D1.

[0053] For example, such as Figure 8 As shown, the rectifier circuit adopts a single-phase full-bridge rectifier topology, and in each bridge arm of the rectifier circuit, the upper half bridge arm is a switching transistor and the lower half bridge arm is a switching transistor. The above pre-charging process includes two stages. The charging path corresponding to the pre-charging process in one stage is T3 and T6, and the charging path corresponding to the pre-charging process in the other stage is T4 and T5.

[0054] For example, such as Figure 9 As shown, the rectifier circuit adopts a three-phase full-bridge rectifier topology. In each bridge arm of the rectifier circuit, the upper half of the bridge arm is a switching transistor and the lower half of the bridge arm is a diode. The above pre-charging process includes three stages. The charging path corresponding to the pre-charging process of one stage is T7 and D4, the charging path corresponding to the pre-charging process of another stage is T8 and D5, and the charging path corresponding to the pre-charging process of the last stage is T9 and D3.

[0055] For example, such as Figure 10As shown, the rectifier circuit adopts a three-phase full-bridge rectifier topology, and each bridge arm in the rectifier circuit includes two switching transistors. Therefore, the above pre-charging process includes at least three stages. The charging paths corresponding to one stage of the pre-charging process are T10 and T13, the charging paths corresponding to another stage of the pre-charging process are T11 and T14, and the charging paths corresponding to the power conversion in the last stage are T12 and T15.

[0056] S120. During the pre-charging process of each stage, determine whether the voltage across the DC side capacitor branch has reached the set value corresponding to the pre-charging process of this stage.

[0057] If the voltage across the DC-side capacitor branch does not reach the set value corresponding to the pre-charging process in this stage, then step S130 is executed; if the voltage across the DC-side capacitor branch reaches the set value corresponding to the pre-charging process in this stage, then step S140 is executed.

[0058] The set value is the voltage value that the DC-side capacitor branch voltage needs to reach at the end during the pre-charging process of this stage.

[0059] For example, suppose that in the first stage of pre-charging, the voltage across the DC-side capacitor branch is charged from 0V to 50V, and in the second stage of pre-charging, the voltage across the DC-side capacitor branch is charged from 50V to 100V. In the first stage of pre-charging, the set value is 50V, and in the second stage of pre-charging, the set value is 100V.

[0060] S130, It is determined that an abnormality has occurred in the pre-charging process of this stage.

[0061] S140. Determine that no abnormality has occurred in the pre-charging process of this stage, and continue the soft start process of the pitch drive.

[0062] Since each pre-charging stage includes only one charging path, if it is determined during a certain pre-charging stage that the voltage across the DC-side capacitor branch on the DC side of the rectifier circuit does not reach the set value corresponding to this pre-charging stage, it can be detected that the switching transistor in the charging path corresponding to this pre-charging stage is not working properly. Furthermore, since the pre-charging process of the DC-side capacitor branch is divided into at least two stages during the soft start of the pitch driver, and the charging paths corresponding to all stages cover all switching transistors, this method can detect whether each switching transistor in the pitch driver is not working properly. Additionally, since all the aforementioned switching transistors are current-type devices, this control method allows a pitch driver with current-type switching transistors to detect whether each of its own switching transistors is not working properly during its soft start. This avoids phase loss operation of the pitch driver, thus preventing large fluctuations in the DC-side voltage of the pitch driver, thereby preventing torque pulsation in the pitch motor, maintaining stable operation of the pitch motor, and potentially even preventing any impact on the normal discharge of the wind turbine.

[0063] It should be noted that although the charging path corresponding to each stage of the pre-charging process sometimes includes both the switching transistor and the diode, the possibility of diode failure is small, so the possibility of diode failure can be ignored.

[0064] In addition, even without ignoring the possibility of diode failure, this control method can at least detect whether each charging path is not working properly. Therefore, it can also avoid the single-phase operation of the pitch driver, that is, avoid large fluctuations in the DC side voltage of the pitch driver, thereby avoiding torque pulsation of the pitch motor, that is, maintaining the stable operation of the pitch motor, and may even avoid affecting the normal discharge of the wind turbine.

[0065] It is worth noting that this control method only optimizes the strategy and therefore does not increase hardware costs.

[0066] Another embodiment of this application provides another implementation of the control method for a pitch drive, the specific structure of which is as follows: Figure 2 As shown, this embodiment, after step S130 in the above embodiment, further includes the following step:

[0067] S210, Perform the protection steps for the pitch drive.

[0068] This embodiment provides one implementation of step S210, the specific structure of which is as follows: Figure 3 As shown, the specific steps include:

[0069] S310, Control the pitch drive to stop.

[0070] It should be noted that controlling the pitch drive to stop is a relatively mature technology, and will not be elaborated on here.

[0071] The above is only one implementation of step S210. In practical applications, it includes, but is not limited to, this. It is not specifically limited here and can be determined according to the specific situation. All of them are within the protection scope of this application.

[0072] Another embodiment of this application provides another implementation of the control method for a pitch drive, the specific structure of which can be found in [reference needed]. Figure 4 ( Figure 4 exist Figure 3 Based on the existing display, but to simplify the view... Figure 3 As shown in the figure (the steps are omitted), this embodiment, based on the embodiment provided above, further includes the following steps:

[0073] S410. During the operation of the pitch driver, determine whether the voltage fluctuation across the DC side capacitor branch exceeds the preset range.

[0074] If the voltage fluctuation across the DC-side capacitor branch does not exceed the preset range, then step S420 is executed; if the voltage fluctuation across the DC-side capacitor branch exceeds the preset range, then step S440 is executed.

[0075] The preset amplitude range is a range of amplitude fluctuations set to eliminate voltage fluctuations across the DC-side capacitor branch caused by error factors. That is, when the voltage fluctuation amplitude across the DC-side capacitor branch exceeds the preset amplitude range, it indicates that the voltage fluctuation across the DC-side capacitor branch is not caused by error factors, but by the rectifier circuit.

[0076] In practical applications, the preset amplitude range is set according to specific circumstances; in an ideal environment, the preset amplitude range can be equal to zero.

[0077] S420. Determine whether the fluctuation frequency of the voltage across the DC-side capacitor branch exceeds the preset frequency range.

[0078] If the fluctuation frequency of the voltage across the DC-side capacitor branch does not exceed the preset frequency range, then step S430 is executed; if the fluctuation frequency of the voltage across the DC-side capacitor branch exceeds the preset frequency range, then step S440 is executed.

[0079] The preset frequency range is a frequency fluctuation range set to eliminate voltage fluctuations across the DC-side capacitor branch caused by error factors. That is, when the fluctuation frequency of the voltage across the DC-side capacitor branch exceeds the preset frequency range, it indicates that the voltage fluctuation across the DC-side capacitor branch is not caused by error factors, but by the rectifier circuit.

[0080] S430, It is determined that there is no abnormality in the rectifier circuit.

[0081] S440, It is determined that the rectifier circuit is malfunctioning.

[0082] This embodiment also provides another implementation of the control method for the pitch drive, the specific structure of which can be found in [reference needed]. Figure 5 ( Figure 5 exist Figure 3 Based on the existing display, but to simplify the view... Figure 3 (The steps in the above embodiments are omitted). This implementation method, based on the implementation method provided in the above embodiments, also includes the following steps:

[0083] S510. During the operation of the pitch driver, determine whether the fluctuation frequency of the voltage across the DC side capacitor branch exceeds the preset frequency range.

[0084] If the fluctuation frequency of the voltage across the DC-side capacitor branch does not exceed the preset frequency range, then step S520 is executed; if the fluctuation frequency of the voltage across the DC-side capacitor branch exceeds the preset frequency range, then step S540 is executed.

[0085] It should be noted that the description of the preset frequency range is the same as that in the above implementation method, and will not be repeated here.

[0086] S520. Determine whether the voltage fluctuation range across the DC-side capacitor branch exceeds the preset range.

[0087] If the voltage fluctuation across the DC-side capacitor branch does not exceed the preset range, then step S530 is executed; if the voltage fluctuation across the DC-side capacitor branch exceeds the preset range, then step S540 is executed.

[0088] It should be noted that the description of the preset amplitude range is the same as that in the above implementation method, and will not be repeated here.

[0089] S530, It is determined that there is no abnormality in the rectifier circuit.

[0090] S540, It is determined that the rectifier circuit is malfunctioning.

[0091] In the two embodiments described above, by adding steps S410 and S420, or adding steps S510 and S520, the control method can perform online diagnosis of the rectifier circuit's function, that is, diagnose in real time whether the switching transistors in the rectifier circuit are not working properly, thus ensuring the stability and safety of the pitch in real time.

[0092] Another embodiment of this application provides another implementation of the control method for a pitch drive, the specific structure of which can be found in [reference needed]. Figure 6 ( Figure 6 Only Figure 4 Based on the above embodiments, this implementation method, after step S440 or step S540, further includes the following steps:

[0093] S610, Perform the protection steps for the pitch drive.

[0094] It should be noted that the implementation method of step S610 is the same as that of step S210, and will not be described again here.

[0095] Another embodiment of this application provides a pitch drive, the specific structure of which can be found in [reference needed]. Figures 7-10 Specifically, it includes: a rectifier circuit 10, a DC-side capacitor branch 20, a controller 30, and at least two voltage sampling circuits 40; the connection relationships between the components are as follows:

[0096] The AC side of the rectifier circuit 10 is connected to the AC power supply 50, and the DC side of the rectifier circuit 10 is connected to the power supply terminal of the pitch motor; the two ends of the DC side capacitor branch 20 are respectively connected to the two poles of the DC side of the rectifier circuit 10.

[0097] The rectifier circuit 10 adopts a full-bridge rectifier topology, and all the switching transistors in the rectifier circuit 10 are current-mode devices.

[0098] Optionally, the rectifier circuit 10 can adopt a single-phase rectifier topology, such as... Figure 7 or Figure 8 As shown; a three-phase rectifier topology can also be used, such as Figure 9 or Figure 10 As shown; no specific limitation is made here, which may be determined depending on the specific circumstances, and all are within the scope of protection of this application.

[0099] Optionally, the current-source device can be a thyristor, such as Figures 7-10 As shown, in practical applications, including but not limited to this, no specific limitation is made here, and it can be determined according to the specific circumstances, all of which are within the protection scope of this application.

[0100] The DC-side capacitor branch 20 includes at least one DC-side capacitor. When the number of DC-side capacitors is greater than one, all DC-side capacitors are connected in series and parallel; for example, Figures 7-10 As shown, the DC-side capacitor branch 20 includes DC-side capacitors C1 and C2 connected in series.

[0101] In a specific example, in each bridge arm of the rectifier circuit 10, the upper half-bridge arm is a switching transistor, and the lower half-bridge arm is a diode. The cathode of the diode in the lower half-bridge arm is connected to the output terminal of the switching transistor in the upper half-bridge arm; for example, as... Figure 7 As shown, the output terminal of switch T1 is connected to the cathode of diode D1, and the output terminal of switch T2 is connected to the cathode of diode D2.

[0102] In another specific example, in each bridge arm of the rectifier circuit 10, the upper half-bridge arm is a switching transistor and the lower half-bridge arm is a switching transistor, with the output terminal of the switching transistor in the upper half-bridge arm connected to the input terminal of the switching transistor in the lower half-bridge arm; for example, as Figure 8 As shown, the output terminal of switch T3 is connected to the input terminal of switch T5, and the output terminal of switch T4 is connected to the input terminal of switch T6.

[0103] The two examples above only illustrate two implementation methods of the bridge arm in the rectifier circuit 10. No specific limitation is made here, and the specific method can be determined according to the specific situation. All of them are within the protection scope of this application.

[0104] All voltage sampling circuits 40 are connected to the controller 30. One voltage sampling circuit 40 is used to sample the DC side voltage of the rectifier circuit 10, and the remaining voltage sampling circuits 40 are used to sample the voltage between each pair of connection terminals on the AC side of the rectifier circuit 10. The rectifier circuit 10 is controlled by the controller 30, which is used to execute the control method provided in the above embodiment.

[0105] If the rectifier circuit 10 can adopt a single-phase rectifier topology, it includes two voltage sampling circuits 40, one sampling the DC side voltage of the rectifier circuit 10 and the other sampling the AC side voltage of the rectifier circuit 10.

[0106] If the rectifier circuit 10 can adopt a three-phase rectifier topology, it includes four voltage sampling circuits 40: one sampling the DC side voltage of the rectifier circuit 10, and the other three sampling the three line voltages on the AC side of the rectifier circuit 10.

[0107] In a specific example, the voltage sampling circuit 40 all adopts a differential sampling topology, for example... Figures 7-10 The operational amplifier (OP) in the application; in practical applications, no specific limitation is made here, and it can be determined according to the specific situation, all of which are within the protection scope of this application.

[0108] This embodiment also provides another implementation of the pitch driver, which, based on the above-described implementation, further includes an inverter circuit.

[0109] The DC side of the rectifier circuit 10 is connected to the DC side of the inverter circuit, and the AC side of the inverter circuit is connected to the power supply terminal of the pitch motor; the inverter circuit is controlled by the controller 30.

[0110] It should be noted that the inverter circuit is a mature circuit structure in the existing technology, and its specific structure and function will not be described in detail here.

[0111] This embodiment also provides another implementation of the pitch driver, which, based on the above implementation, further includes a DC / DC conversion circuit.

[0112] The DC side of the rectifier circuit 10 is connected to the first side of the DC / DC converter circuit, and the second side of the DC / DC converter circuit is connected to the power supply terminal of the pitch motor; the DC / DC converter circuit is controlled by the controller 30.

[0113] It should be noted that the DC / DC converter circuit is a mature circuit structure in the existing technology, and its specific structure and function will not be described in detail here.

[0114] The above are only three implementations of the pitch drive, and are not specifically limited here. They can be determined according to the specific circumstances, and are all within the protection scope of this application.

[0115] The features described above in the disclosed embodiments can be substituted or combined with each other, enabling those skilled in the art to implement or use this application. The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention in any way. Although the present invention has been disclosed above with reference to preferred embodiments, it is not intended to limit the invention. Any person skilled in the art can make many possible variations and modifications to the technical solutions of the present invention using the methods and techniques disclosed above, or modify them into equivalent embodiments with equivalent changes, without departing from the scope of the present invention. Therefore, any simple modifications, equivalent changes, and modifications made to the above embodiments based on the technical essence of the present invention without departing from the content of the present invention's technical solutions still fall within the protection scope of the present invention.

Claims

1. A control method for a pitch drive, characterized in that, The rectifier circuit in the pitch driver adopts a full-bridge rectifier topology, and all the switching transistors in the rectifier circuit are current-type devices. A DC-side capacitor branch is provided on the DC side of the rectifier circuit. The control method includes: During the soft start process of the pitch driver, the pre-charging process of the DC side capacitor branch is divided into at least two stages and carried out one by one; each stage of the pre-charging process includes only one charging path, and the charging paths corresponding to the pre-charging processes of all stages cover all the switching transistors. During the pre-charging process at each stage, it is determined whether the voltage across the DC-side capacitor branch reaches the set value corresponding to the pre-charging process at this stage. If the voltage across the DC-side capacitor branch does not reach the set value corresponding to the pre-charging process in this stage, then the pre-charging process in this stage is determined to be abnormal.

2. The control method for the pitch drive according to claim 1, characterized in that, After determining that an anomaly has occurred in the pre-charging process at this stage, the following steps are also included: Perform the protection steps for the pitch drive.

3. The control method for the pitch drive according to claim 2, characterized in that, Performing the protection steps of the pitch drive includes: Control the pitch drive to stop.

4. The control method for the pitch drive according to claim 1, characterized in that, If the voltage across the DC-side capacitor branch reaches the set value corresponding to the pre-charging process in this stage, it is determined that the pre-charging process in this stage has not been abnormal, and the soft start process of the pitch driver continues.

5. The control method for the pitch drive according to any one of claims 1 to 4, characterized in that, Also includes: During the operation of the pitch driver, if the voltage fluctuation amplitude at both ends of the DC-side capacitor branch exceeds a preset amplitude range, and / or the voltage fluctuation frequency at both ends of the DC-side capacitor branch exceeds a preset frequency range, then the rectifier circuit is determined to be malfunctioning.

6. The control method for the pitch drive according to claim 5, characterized in that, After determining that the rectifier circuit is malfunctioning, the process also includes: Perform the protection steps for the pitch drive.

7. A pitch drive, characterized in that, include: The circuit consists of a rectifier circuit, a DC-side capacitor branch, a controller, and at least two voltage sampling circuits; wherein: The AC side of the rectifier circuit is connected to an AC power source, and the DC side of the rectifier circuit is connected to the power supply terminal of the pitch motor. The two ends of the DC-side capacitor branch are respectively connected to the two poles of the DC side of the rectifier circuit; All of the voltage sampling circuits are connected to the controller. One voltage sampling circuit is used to sample the DC side voltage of the rectifier circuit, and the remaining voltage sampling circuits are used to sample the voltage between every two connection terminals on the AC side of the rectifier circuit. The rectifier circuit is controlled by the controller, which is used to perform the control method as described in any one of claims 1 to 6.

8. The pitch drive according to claim 7, characterized in that, The rectifier circuit adopts a three-phase rectifier topology or a single-phase rectifier topology.

9. The pitch drive according to claim 7, characterized in that, In each bridge arm of the rectifier circuit, the upper half of the bridge arm is a switching transistor and the lower half of the bridge arm is a diode. The cathode of the diode in the lower half of the bridge arm is connected to the output terminal of the switching transistor in the upper half of the bridge arm. or, In each bridge arm of the rectifier circuit, the upper half of the bridge arm is a switching transistor, and the lower half of the bridge arm is a switching transistor. The output terminal of the switching transistor in the upper half of the bridge arm is connected to the input terminal of the switching transistor in the lower half of the bridge arm.

10. The pitch drive according to claim 7, characterized in that, The switching transistor in the pitch driver is a thyristor.

11. The pitch drive according to claim 7, characterized in that, Each of the voltage sampling circuits employs a differential sampling topology.

12. The pitch drive according to any one of claims 7 to 11, characterized in that, Also includes: Inverter circuit; where: The DC side of the rectifier circuit is connected to the DC side of the inverter circuit, and the AC side of the inverter circuit is connected to the power supply terminal of the pitch motor. The inverter circuit is controlled by the controller.

13. The pitch drive according to any one of claims 7 to 11, characterized in that, Also includes: DC / DC converter circuit; wherein: The DC side of the rectifier circuit is connected to the first side of the DC / DC converter circuit, and the second side of the DC / DC converter circuit is connected to the power supply terminal of the pitch motor. The DC / DC conversion circuit is controlled by the controller.

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