阅读说明：本技术 输入为可控整流的变桨伺服驱动器及其驱动方法 (Variable-pitch servo driver with controllable rectification input and driving method thereof ) 是由 陈志领 陆卫丽 肖庆恩 于 2020-12-23 设计创作，主要内容包括：本发明提供一种输入为可控整流的变桨伺服驱动器及其驱动方法,所述驱动器包括三相交流电检测单元、可控整流模块、上电缓冲单元、辅助电源、控制单元以及储能电容,所述三相交流电检测单元、可控整流模块、上电缓冲单元的输入端均与三相交流电相连,所述上电缓冲单元的输出端与所述可控整流模块的输出端相连,所述可控整流模块的输出端与所述储能电容相连并进而与所述辅助电源的输入端相连,所述辅助电源的输出端与所述控制单元的电源输入端相连,所述控制单元与所述可控整流模块相连,提供整流控制信号。与不可控的二极管整流电路相比可控整流的直流母线电压比较稳定,有利于驱动器输出的稳定控制。(The invention provides a variable-pitch servo driver with controllable rectification as input and a driving method thereof, wherein the driver comprises a three-phase alternating current detection unit, a controllable rectification module, a power-on buffering unit, an auxiliary power supply, a control unit and an energy storage capacitor, wherein the input ends of the three-phase alternating current detection unit, the controllable rectification module and the power-on buffering unit are all connected with three-phase alternating current, the output end of the power-on buffering unit is connected with the output end of the controllable rectification module, the output end of the controllable rectification module is connected with the energy storage capacitor and further connected with the input end of the auxiliary power supply, the output end of the auxiliary power supply is connected with the power supply input end of the control unit, and the control unit is connected with the controllable rectification module to provide a rectification control signal. Compared with an uncontrollable diode rectifying circuit, the direct-current bus voltage of controllable rectification is stable, and stable control of driver output is facilitated.)

1. A variable-pitch servo driver with controllable rectification as input is characterized by comprising a three-phase alternating current detection unit, a controllable rectification module, an electrifying buffer unit, an auxiliary power supply, a control unit and an energy storage capacitor, wherein the input ends of the three-phase alternating current detection unit, the controllable rectification module and the electrifying buffer unit are all connected with three-phase alternating current, the output end of the electrifying buffer unit is connected with the output end of the controllable rectification module, the output end of the controllable rectification module is connected with the energy storage capacitor and further connected with the input end of the auxiliary power supply, the output end of the auxiliary power supply is connected with the power supply input end of the control unit, the control unit is connected with the controllable rectification module to provide rectification control signals, the control unit is also connected with the electrifying buffer unit to provide delay switch signals, the control unit is also connected with the three-phase alternating current detection unit and receives a three-phase alternating current detection signal provided by the three-phase alternating current detection unit.

2. The driver of claim 1, wherein the controllable rectifying module comprises a rectifying bridge, a lower bridge arm of the rectifying bridge is three uncontrollable diodes, and an upper bridge arm of the rectifying bridge is three thyristors, and the controllable rectifying bridge receives the rectifying control signals provided by the control unit respectively.

3. The driver of claim 1, wherein the power-up buffer unit comprises three diodes, a first resistor and a controllable switch, anodes of the three diodes are respectively connected to three-phase alternating current, cathodes of the three diodes are all connected to a first end of the first resistor, a second end of the first resistor is connected to a first end of the controllable switch, a second end of the controllable switch is connected to the controllable rectifying module, the controllable switch further has a signal input end receiving the delay switch signal, and the controllable switch is in a normally-off state.

4. The driver of claim 1, wherein the energy storage capacitor is connected in parallel across the output of the controllable rectifier module.

5. The driver of claim 1, wherein the control unit is further connected to the output terminal of the controllable rectifier module through a dc bus voltage detection unit for detecting the dc bus voltage outputted by the controllable rectifier module.

6. A method of driving a pitch servo drive with a controllable commutation as an input, using a drive according to claim 1, characterized in that the method comprises the steps of:

step S1, three-phase alternating current is switched on, the three-phase alternating current passes through the power-on buffer unit and the controllable rectifying module to form a closed loop, and the direct-current bus voltage output by the controllable rectifying module and the energy storage capacitor are electrified and raised;

step S2, when the DC bus voltage reaches above the lowest working voltage of the auxiliary power supply, the auxiliary power supply starts working to output the low-voltage DC voltage needed by the control unit and the three-phase AC detection unit;

step S3, the control unit and the three-phase alternating current detection unit obtain the required low-voltage direct current voltage to start working;

step S4, the control unit outputs a rectification control signal according to the three-phase alternating current detection signal provided by the three-phase alternating current detection unit to drive the controllable rectification module to normally work, and the controllable rectification module starts to supply power to the system;

step S5, the control unit outputs a delay switch signal to control the power-on buffer unit to disconnect from the controllable rectifier module;

step S6, the control unit adjusts the rectification control signal in real time according to the three-phase ac detection signal provided by the three-phase ac detection unit in real time, so that the controllable rectification module outputs a stable dc bus voltage;

step S7, when the dc bus voltage cannot be stabilized within the normal range, the control unit controls the controllable rectification module to turn off through the rectification control signal, controls the driver to stop outputting the overvoltage fault, outputs the delay switch signal to control the power-on buffer unit to turn on the controllable rectification module, and repeats steps S2-S6.

7. The driving method according to claim 6, wherein the controllable rectifier module comprises a rectifier bridge, a lower bridge arm of the rectifier bridge is three uncontrollable diodes, an upper bridge arm of the rectifier bridge is three thyristors, and the controllable rectifiers receive rectification control signals provided by the control unit respectively; in the step S1, the power-on buffer unit and the controllable rectifier module form a closed loop, and the power-on buffer unit and the lower bridge arm of the rectifier bridge in the controllable rectifier module form a closed loop; in step S7, the power-on buffer unit is connected to the controllable rectifier module, and the power-on buffer unit is connected to a lower bridge arm of a rectifier bridge in the controllable rectifier module.

8. The driving method according to claim 6, wherein the power-on buffer unit includes three diodes, a first resistor, and a controllable switch, anodes of the three diodes are respectively connected to three-phase alternating current, cathodes of the three diodes are connected to a first end of the first resistor, a second end of the first resistor is connected to a first end of the controllable switch, a second end of the controllable switch is connected to the controllable rectifying module, the controllable switch further has a signal input end receiving the delay switch signal, and the controllable switch is in a normally-off state.

9. The driving method according to claim 7, wherein the three-phase alternating current detection signal includes a three-phase alternating current voltage, a phase angle; the rectification control signal is used for controlling the conduction phase angle of the rectifier bridge.

10. The driving method according to claim 6, wherein the control unit is further connected to an output terminal of the controllable rectifier module through a dc bus voltage detection unit, and detects the dc bus voltage output by the controllable rectifier module to generate the rectifier control signal.

Technical Field

The invention relates to the technical field of wind power generation, in particular to a servo driver used for a wind power generation variable pitch system and a driving method thereof.

Background

At present, a rectification circuit of a main flow of a variable pitch servo driver is an uncontrollable three-phase full-bridge rectification bridge formed by 6 diodes, and then rectified into relatively stable direct current after being filtered by a capacitor. The relationship between the rectified dc voltage Udc and the input three-phase ac voltage Uac is Udc = √ 2 √ Uac. The formula shows that the rectified and filtered direct-current bus voltage Udc and the power grid input three-phase alternating-current voltage Uac are in a linear relation, the direct-current bus voltage Udc can be reduced or increased along with the reduction of the input three-phase alternating-current voltage Uac, and when the direct-current bus voltage Udc is higher than the upper limit of the safety voltage set by the driver, the driver can report the input overvoltage/bus overvoltage fault and stop working. From the above, the main problem of the circuit is that the rectified direct current bus voltage Udc is uncontrollable, and when the power grid is unstable, the driver is easy to have abnormal bus voltage and report faults.

The wind power industry in China is vigorously developed, the loading amount is steadily increased, and important contributions are made to the effective utilization of green energy in China, the blue sky and the realization of sustainable development. However, most wind generating sets are installed in remote areas with bad natural conditions, especially mountainous areas, and the problems of unstable power grid and low power quality of the power grid of the remote areas generally exist. The variable pitch system is an important component of the wind generating set, and the servo driver is a core component for variable pitch. The input rectification of the existing variable pitch driver is mostly uncontrollable, when the fluctuation of the voltage of a power grid is too large or the harmonic pollution is serious, the bus voltage of the driver exceeds the normal voltage range, the driver frequently reports the input overvoltage/bus overvoltage fault, and the normal power generation is influenced and the potential safety hazard is generated. For this reason, it is urgently needed to develop a pitch servo driver with controllable rectification as input to solve the problem.

Disclosure of Invention

In view of the defects of the prior art, the invention aims to provide a pitch servo driver with controllable rectification as input, which has higher safety, and a driving method thereof.

In order to achieve the above purpose, the embodiment of the invention adopts the following technical scheme:

a variable-pitch servo driver with controllable rectification as input comprises a three-phase alternating current detection unit, a controllable rectification module, a power-on buffering unit, an auxiliary power supply, a control unit and an energy storage capacitor, wherein the input ends of the three-phase alternating current detection unit, the controllable rectification module and the power-on buffering unit are all connected with three-phase alternating current, the output end of the power-on buffering unit is connected with the output end of the controllable rectification module, the output end of the controllable rectification module is connected with the energy storage capacitor and further connected with the input end of the auxiliary power supply, the output end of the auxiliary power supply is connected with the power supply input end of the control unit, the control unit is connected with the controllable rectification module to provide rectification control signals, the control unit is also connected with the power-on buffering unit to provide delay switch signals, and the control unit is also connected with the three-phase alternating current detection unit, and receiving a three-phase alternating current detection signal provided by the three-phase alternating current detection unit.

Further, the controllable rectifier module comprises a rectifier bridge, a lower bridge arm of the rectifier bridge is three uncontrollable diodes, and an upper bridge arm of the rectifier bridge is three controllable silicon, and receives the rectification control signals provided by the control unit respectively.

Further, the power-on buffer unit comprises three diodes, a first resistor and a controllable switch, the anodes of the three diodes are respectively connected with three-phase alternating current, the cathodes of the three diodes are connected with the first end of the first resistor, the second end of the first resistor is connected with the first end of the controllable switch, the second end of the controllable switch is connected with the controllable rectifying module, the controllable switch is further provided with a signal input end for receiving the delay switch signal, and the controllable switch is in a normally-closed state.

Further, the energy storage capacitor is connected in parallel with two ends of the output end of the controllable rectifying module.

Furthermore, the control unit is connected with the output end of the controllable rectifying module through a direct current bus voltage detection unit, and detects the direct current bus voltage output by the controllable rectifying module.

A method of driving a pitch servo drive with a controllable rectifier input, using a drive as hereinbefore described, the method comprising the steps of:

step S1, three-phase alternating current is switched on, the three-phase alternating current passes through the power-on buffer unit and the controllable rectifying module to form a closed loop, and the direct-current bus voltage output by the controllable rectifying module and the energy storage capacitor are electrified and raised;

step S2, when the DC bus voltage reaches above the lowest working voltage of the auxiliary power supply, the auxiliary power supply starts working to output the low-voltage DC voltage needed by the control unit and the three-phase AC detection unit;

step S3, the control unit and the three-phase alternating current detection unit obtain the required low-voltage direct current voltage to start working;

step S4, the control unit outputs a rectification control signal according to the three-phase alternating current detection signal provided by the three-phase alternating current detection unit to drive the controllable rectification module to normally work, and the controllable rectification module starts to supply power to the system;

step S5, the control unit outputs a delay switch signal to control the power-on buffer unit to disconnect from the controllable rectifier module;

step S6, the control unit adjusts the rectification control signal in real time according to the three-phase ac detection signal provided by the three-phase ac detection unit in real time, so that the controllable rectification module outputs a stable dc bus voltage;

step S7, when the dc bus voltage cannot be stabilized within the normal range, the control unit controls the controllable rectification module to turn off through the rectification control signal, controls the driver to stop outputting the overvoltage fault, outputs the delay switch signal to control the power-on buffer unit to turn on the controllable rectification module, and repeats steps S2-S6.

Further, the controllable rectifier module comprises a rectifier bridge, a lower bridge arm of the rectifier bridge is three uncontrollable diodes, an upper bridge arm of the rectifier bridge is three controllable silicon, and the controllable rectifier module receives rectification control signals provided by the control unit respectively; in the step S1, the power-on buffer unit and the controllable rectifier module form a closed loop, and the power-on buffer unit and the lower bridge arm of the rectifier bridge in the controllable rectifier module form a closed loop; in step S7, the power-on buffer unit is connected to the controllable rectifier module, and the power-on buffer unit is connected to a lower bridge arm of a rectifier bridge in the controllable rectifier module.

Further, the power-on buffer unit comprises three diodes, a first resistor and a controllable switch, the anodes of the three diodes are respectively connected with three-phase alternating current, the cathodes of the three diodes are connected with the first end of the first resistor, the second end of the first resistor is connected with the first end of the controllable switch, the second end of the controllable switch is connected with the controllable rectifying module, the controllable switch is further provided with a signal input end for receiving the delay switch signal, and the controllable switch is in a normally-closed state.

Further, the three-phase alternating current detection signal comprises a three-phase alternating current voltage and a phase angle; the rectification control signal is used for controlling the conduction phase angle of the rectifier bridge.

Further, the control unit is connected with the output end of the controllable rectification module through a direct current bus voltage detection unit, and detects the direct current bus voltage output by the controllable rectification module to generate the rectification control signal.

The invention relates to a variable-pitch servo driver with controllable rectification as input and a driving method thereof.A rectifier bridge adopts silicon controlled rectifier, and the rectifier bridge is shut down and stops outputting overvoltage faults (namely faults are not reported) when the voltage of a direct current bus exceeds a normal range through the cooperation of an electrifying buffer unit and an auxiliary power supply, so that a system is slowly recovered to be normal by temporarily supplying power to the electrifying buffer unit and the auxiliary power supply, and then the rectifier bridge is started to normally work. Compared with an uncontrollable diode rectifying circuit, the direct-current bus voltage of controllable rectification is more stable, and the stable control of the output of the driver is facilitated; and the adaptability of the driver to the power grid is increased, the failure rate of the driver caused by instability of the power grid can be reduced, the safety is improved, the power generation time is increased, and the loss is reduced.

Drawings

In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the drawings needed to be used in the embodiments will be briefly described below, and it is obvious that the drawings in the following description are only some embodiments of the present invention, and it is obvious for those skilled in the art that other drawings can be obtained according to these drawings without creative efforts.

FIG. 1 is a block diagram of a pitch servo driver with controllable rectification as an input according to an embodiment of the present invention;

fig. 2 is a schematic flow chart of a driving method of a pitch servo driver with controllable rectification as an input according to an embodiment of the present invention.

Detailed Description

The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

Referring to fig. 1, a pitch servo driver with controllable rectification as an input according to an embodiment of the present invention includes a three-phase ac detection unit, a controllable rectification module, a power-on buffer unit, an auxiliary power supply, a control unit, and an energy storage capacitor, where input ends of the three-phase ac detection unit, the controllable rectification module, and the power-on buffer unit are all connected to a three-phase ac, an output end of the power-on buffer unit is connected to an output end of the controllable rectification module, an output end of the controllable rectification module is connected to the energy storage capacitor and further connected to an input end of the auxiliary power supply, an output end of the auxiliary power supply is connected to a power input end of the control unit, the control unit is connected to the controllable rectification module to provide a rectification control signal, and the control unit is further connected to the power-on buffer unit, and the control unit is also connected with the three-phase alternating current detection unit and receives the three-phase alternating current detection signal provided by the three-phase alternating current detection unit.

The controllable rectifying module comprises a rectifying bridge B1, the lower bridge arm of the rectifying bridge B1 is three uncontrollable diodes, and the upper bridge arm of the rectifying bridge B1 is three controllable silicon which respectively receive rectifying control signals SCR _ DRVA, SCR _ DRVB and SCR _ DRVC provided by the control unit.

The power-on buffer unit comprises three diodes D1, D2, D3, a first resistor R1 and a controllable switch K1, anodes of the three diodes D1, D2 and D3 are respectively connected with three-phase alternating currents LA, LB and LC, cathodes of the three diodes D1, D2 and D3 are respectively connected with a first end of the first resistor R1, a second end of the first resistor R1 is connected with a first end of the controllable switch K1, a second end of the controllable switch K1 is connected with the controllable rectifying module, the controllable switch K1 is further provided with a signal input end which receives the delay switch signal RELAY1_ DRV, and the controllable switch K1 is in a normally-closed state. Of course, the controllable switch K1 also has a ground GND.

The energy storage capacitor C1 is connected in parallel with DC + and DC-at two ends of the output end of the controllable rectifying module.

The control unit is also connected with the output end of the controllable rectifying module through a direct current bus voltage detection unit, and detects the direct current bus voltage DC + output by the controllable rectifying module. Of course, the dc bus voltage detection unit is also connected to the auxiliary power supply, and the auxiliary power supply provides the operating voltage.

Referring to fig. 2, in an embodiment of the present invention, a driving method of a pitch servo driver with controllable rectification as an input is adopted in the driver, where the driving method includes the following steps:

step S1, three-phase alternating current is switched on, the three-phase alternating current passes through the power-on buffer unit and the controllable rectifying module to form a closed loop, and the direct-current bus voltage output by the controllable rectifying module and the energy storage capacitor are electrified and raised;

step S2, when the DC bus voltage reaches above the lowest working voltage of the auxiliary power supply, the auxiliary power supply starts working to output the low-voltage DC voltage needed by the control unit and the three-phase AC detection unit;

step S3, the control unit and the three-phase alternating current detection unit obtain the required low-voltage direct current voltage to start working;

step S4, the control unit outputs a rectification control signal according to the three-phase alternating current detection signal provided by the three-phase alternating current detection unit to drive the controllable rectification module to normally work, and the controllable rectification module starts to supply power to the system;

step S5, the control unit outputs a delay switch signal to control the power-on buffer unit to disconnect from the controllable rectifier module;

step S6, the control unit adjusts the rectification control signal in real time according to the three-phase ac detection signal provided by the three-phase ac detection unit in real time, so that the controllable rectification module outputs a stable dc bus voltage;

step S7, when the dc bus voltage cannot be stabilized within the normal range, the control unit controls the controllable rectification module to turn off through the rectification control signal, controls the driver to stop outputting the overvoltage fault, outputs the delay switch signal to control the power-on buffer unit to turn on the controllable rectification module, and repeats steps S2-S6.

The controllable rectifying module comprises a rectifying bridge B1, the lower bridge arm of the rectifying bridge B1 is three uncontrollable diodes, the upper bridge arm of the rectifying bridge B1 is three controllable silicon, and the controllable rectifying module respectively receives rectifying control signals SCR _ DRVA, SCR _ DRVB and SCR _ DRVC provided by the control unit; in the step S1, the power-on buffer unit and the controllable rectifier module form a closed loop, and the power-on buffer unit and the lower arm of the rectifier bridge B1 in the controllable rectifier module form a closed loop; in step S7, the power-on buffer unit is connected to the controllable rectifier module, and the power-on buffer unit is connected to the lower arm of the rectifier bridge B1 in the controllable rectifier module.

The power-on buffer unit comprises three diodes D1, D2, D3, a first resistor R1 and a controllable switch K1, anodes of the three diodes D1, D2 and D3 are respectively connected with three-phase alternating currents LA, LB and LC, cathodes of the three diodes D1, D2 and D3 are respectively connected with a first end of the first resistor R1, a second end of the first resistor R1 is connected with a first end of the controllable switch K1, a second end of the controllable switch K1 is connected with the controllable rectifying module, the controllable switch K1 is further provided with a signal input end which receives the delay switch signal RELAY1_ DRV, and the controllable switch K1 is in a normally-closed state. Of course, the controllable switch K1 also has a ground GND.

The three-phase alternating current detection signal comprises three-phase alternating current voltage and a phase angle; the rectification control signal is used for controlling the conducting phase angle of the rectifier bridge B1.

The control unit is also connected with the output end of the controllable rectifying module through a direct current bus voltage detection unit, and detects the direct current bus voltage DC + output by the controllable rectifying module to generate the rectifying control signal.

The invention relates to a variable-pitch servo driver with controllable rectification as input and a driving method thereof.A rectifier bridge adopts silicon controlled rectifier, and the rectifier bridge is shut down and stops outputting overvoltage faults (namely faults are not reported) when the voltage of a direct current bus exceeds a normal range through the cooperation of an electrifying buffer unit and an auxiliary power supply, so that a system is slowly recovered to be normal by temporarily supplying power to the electrifying buffer unit and the auxiliary power supply, and then the rectifier bridge is started to work normally. Compared with an uncontrollable diode rectifying circuit, the direct-current bus voltage of controllable rectification is more stable, and the stable control of the output of the driver is facilitated; and the adaptability of the driver to the power grid is increased, the failure rate of the driver caused by instability of the power grid can be reduced, the safety is improved, the power generation time is increased, and the loss is reduced.

The above description is only an embodiment of the present invention, but the scope of the present invention is not limited thereto, and any changes or substitutions that can be easily conceived by those skilled in the art within the technical scope of the present invention disclosed herein are intended to be covered by the scope of the present invention. Therefore, the protection scope of the present invention shall be subject to the protection scope of the appended claims.