Overvoltage suppression control method of variable-pitch motor controller

Abstract

The invention discloses an overvoltage suppression control method for a variable-pitch motor controller, and the method comprises the steps: carrying out the calculation based on the resistance value of a brake resistor R5 and a bus voltage U, and obtaining a maximum limit value Pmax of the power generation power of a variable-pitch motor; a torque maximum limit value Tlimmax is calculated based on the generated power maximum limit value Pmax of the variable-pitch motor and the rotating speed omega of the variable-pitch motor, the torque Tlim < = the torque maximum limit value Tlimmax of the variable-pitch motor is used as a torque instruction amplitude limiting value of a variable-pitch motor controller for driving operation, and it is ensured that the bus voltage of the controller does not exceed the maximum limit value Umax of the bus voltage; under the condition that cost is not increased and hardware is not changed, the purpose of restraining the bus voltage from being too high is achieved, then the problem that overvoltage faults are frequently reported on site is solved, the power generation efficiency of the wind power generation system is improved, and the safety and reliability of the wind power generation system are improved.

Description

Technical Field

[0001] The invention belongs to the field of wind power generation, and in particular relates to an overvoltage suppression control method for a variable pitch motor controller. Background Art

[0002] In the wind power generation system, the variable pitch motor controller controls the blades to the appropriate angle according to the wind direction and wind speed to maximize the power generation. When the blades change position quickly, if the motor is in the power generation state at this time, the power generation will cause the bus voltage of the variable pitch drive to rise. If the bus capacitance is relatively small, the bus voltage will rise very quickly, and the external braking resistor will not have time to quickly discharge the braking energy, causing the bus voltage to continue to rise, triggering the bus overvoltage alarm, resulting in frequent overvoltage faults on site and causing shutdowns.

[0003] Therefore, the applicant hopes to seek technical solutions to improve the above technical problems. Summary of the invention

[0004] In view of this, the purpose of the present invention is to propose a method for suppressing overvoltage control of a variable pitch motor controller, which achieves the purpose of suppressing excessive bus voltage without increasing costs and changing hardware, thereby solving the problem of frequent overvoltage faults on site, improving the power generation efficiency of the wind power generation system, and increasing the safety and reliability of the wind power generation system.

[0005] To this end, the technical solution adopted in the present invention is as follows: A method for suppressing overvoltage control of a pitch motor controller, wherein the bus voltage of the controller is connected to an inverter module after passing through a rectifier module and a filter module, and the output end of the inverter module is connected to the pitch motor; the input end of the inverter module is externally connected to a braking resistor (R5); wherein the method for suppressing overvoltage control comprises: Based on the resistance value of the braking resistor (R5) and the bus voltage U, a maximum limit value Pmax of the power generation of the pitch motor is calculated; The maximum torque limit Tlim is calculated based on the maximum power limit Pmax of the pitch motor and the speed omega of the pitch motor. max , the torque Tlim of the pitch motor is less than the maximum torque limit Tlim max The variable pitch motor controller is used as the torque command limit value for driving operation to ensure that the controller bus voltage does not exceed the maximum limit value Umax of the bus voltage.

[0006] Preferably, the maximum limit value Umax of the bus voltage = 1.05-1.1 times of the bus voltage U.

[0007] Preferably, the resistance range of the braking resistor (R5) is 18-22 ohms.

[0008] Preferably, the bus voltage U is in the range of 780-820V, and the maximum limit value Umax of the bus voltage is in the range of 850-880V.

[0009] Preferably, the calculation formula for the maximum limit value Pmax of the power generation power of the variable pitch motor is: Pmax=U*U / R5.

[0010] Preferably, the maximum torque limit Tlim max The calculation formula is: max =Pmax / omega.

[0011] Preferably, the bus voltage U is 800V, and the maximum limit value Umax of the bus voltage is in the range of 860-870V.

[0012] Preferably, the maximum limit value Pmax of the power generation power of the variable pitch motor is 32kw.

[0013] Preferably, a braking resistor (R5) and a MOS tube are connected in sequence between the output end of the filter module and the bus voltage between the inverter module; wherein a diode is connected in parallel between the braking resistor (R5) and the bus voltage.

[0014] The present invention implements an overvoltage control method for the pitch motor controller. Based on the principle of conservation of energy, the present invention controls the power generation power of the pitch motor to avoid excessive bus voltage. This achieves the purpose of suppressing excessive bus voltage without increasing costs or changing hardware, thereby solving the problem of frequent overvoltage faults on site, improving the power generation efficiency of the wind power generation system, and increasing the safety and reliability of the wind power generation system. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 It is a schematic diagram of the electrical connection structure between the variable pitch motor controller and the bus voltage in a specific implementation manner of the present application. DETAILED DESCRIPTION

[0016] An embodiment of the present invention discloses a method for suppressing overvoltage control of a variable pitch motor controller, in which the bus voltage of the controller is connected to the inverter module after passing through a rectifier module and a filter module, and the output end of the inverter module is connected to the variable pitch motor; the input end of the inverter module is externally connected to a braking resistor R5; wherein the overvoltage suppression control method includes: calculating the maximum limit value Pmax of the power generation of the variable pitch motor based on the resistance value of the braking resistor R5 and the bus voltage U; calculating the maximum limit value Tlim of the torque based on the maximum limit value Pmax of the power generation of the variable pitch motor and the rotation speed omega of the variable pitch motor max , set the torque Tlim of the pitch motor to ≤ the maximum torque limit Tlim maxIt is used as the torque command limit value of the pitch motor controller for driving operation to ensure that the controller bus voltage does not exceed the maximum limit Umax of the bus voltage.

[0017] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments recorded in the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0018] This embodiment provides a method for suppressing overvoltage control of a pitch motor controller. Figure 1 As shown, the bus voltage of the controller is connected to the inverter module (known structure, which is the core module of the variable pitch motor controller, and the variable pitch motor can be driven by controlling the module) after passing through the rectifier module (known structure, specifically a rectifier bridge stack, which is used to convert the three-phase AC input voltage into a DC voltage) and the filter module (known structure). The output end of the inverter module is connected to the variable pitch motor; the input end of the inverter module is externally connected to a braking resistor R5; wherein, Preferably, in this embodiment, preferably, a braking resistor R5 and a MOS tube a are sequentially connected between the output end of the filter module and the bus voltage between the inverter module; wherein a diode b is connected in parallel between the braking resistor R5 and the bus voltage, specifically a freewheeling diode; In this embodiment, the connection circuit between the controller bus voltage and the inverter module is also provided with the following electrical components: Varistors T1~3 are used to absorb phase-to-phase overvoltage; Y capacitors C1~3 provide a low-impedance path for common-mode interference in the circuit; the busbar varistor T4 is used to absorb busbar overvoltage; the filter absorption capacitor C4, the pre-charge resistor R1 and the switch connected in parallel with it, the switch is used to cut off the pre-charge resistor R1, when the capacitor voltage in the filter module reaches the set voltage, the pre-charge resistor R1 will be cut out of the main circuit; smoothing capacitors C5, C6, equalizing resistors R2, R3; resistor R4 and the light-emitting diode connected to it are used to indicate whether the busbar capacitor has power.

[0019] Preferably, in this embodiment, the resistance range of the brake resistor R5 is 18-22 ohms; the range of the bus voltage U is 780-820V, and the range of the maximum limit value Umax of the bus voltage is 850-880V; preferably, the maximum limit value Umax of the bus voltage = 1.05-1.1 times the bus voltage U; In this embodiment, the overvoltage suppression control method includes: calculating the maximum limit value Pmax of the power generation power of the pitch motor based on the resistance value of the braking resistor R5 and the bus voltage U; wherein the calculation formula of the maximum limit value Pmax of the power generation power of the pitch motor is: Pmax=U*U / R5; The maximum torque limit Tlim is calculated based on the maximum power limit Pmax of the variable pitch motor and the speed omega of the variable pitch motor. max , set the torque Tlim of the pitch motor to ≤ the maximum torque limit Tlim max As the torque command limit value of the pitch motor controller, it drives the operation to ensure that the controller bus voltage does not exceed the maximum limit of the bus voltage Umax; among which, the maximum torque limit Tlim max The calculation formula is: max =Pmax / omega; Specifically, in this embodiment, the braking resistor R5 is 20 ohms, the bus voltage U is 800V, and the maximum limit Umax of the bus voltage is 864V; the maximum limit Pmax of the variable pitch motor power generation is calculated to be 32kw; the maximum limit Tlim max =32000 / omega, where Tlim max The unit of is N*m, the unit of omega is rad / s.

[0020] Without increasing costs or changing hardware, this embodiment implements an overvoltage control method for the pitch motor controller. Based on the principle of conservation of energy, it controls the power generation of the pitch motor to avoid excessive bus voltage, thereby achieving the purpose of suppressing excessive bus voltage, and further solving the problem of frequent overvoltage faults on site, thereby improving the power generation efficiency of the wind power generation system and increasing the safety and reliability of the wind power generation system.

[0021] It will be apparent to those skilled in the art that the invention is not limited to the details of the exemplary embodiments described above and that the invention can be implemented in other specific forms without departing from the spirit or essential features of the invention. Therefore, the embodiments should be considered exemplary and non-limiting in all respects, and the scope of the invention is defined by the appended claims rather than the foregoing description, and it is intended that all variations falling within the meaning and scope of the equivalent elements of the claims be included in the invention. Any reference numeral in a claim should not be considered as limiting the claim to which it relates.

[0022] In addition, it should be understood that although the present specification is described according to implementation modes, not every implementation mode contains only one independent technical solution. This description of the specification is only for the sake of clarity. Those skilled in the art should regard the specification as a whole. The technical solutions in each embodiment may also be appropriately combined to form other implementation modes that can be understood by those skilled in the art.

Claims

1. A method for suppressing overvoltage control of a pitch motor controller, wherein the bus voltage of the controller is connected to an inverter module after passing through a rectifier module and a filter module, and the output end of the inverter module is connected to the pitch motor; characterized in that: The input end of the inverter module is externally connected to a braking resistor (R5); wherein the overvoltage suppression control method comprises: Based on the resistance value of the braking resistor (R5) and the bus voltage U, a maximum limit value Pmax of the power generation of the pitch motor is calculated; The maximum torque limit Tlim is calculated based on the maximum power limit Pmax of the pitch motor and the speed omega of the pitch motor. max , the torque Tlim of the pitch motor is less than the maximum torque limit Tlim max The variable pitch motor controller is used as the torque command limit value for driving operation to ensure that the controller bus voltage does not exceed the maximum limit value Umax of the bus voltage.

2. The method for suppressing overvoltage control of a pitch motor controller according to claim 1, characterized in that: The maximum limit of the bus voltage Umax=1.05-1.1 times the bus voltage U.

3. The overvoltage suppression control method of the pitch motor controller according to claim 1 is characterized in that: The resistance of the brake resistor (R5) ranges from 18 to 22 ohms.

4. The method for suppressing overvoltage control of a pitch motor controller according to claim 1, characterized in that: The bus voltage U ranges from 780V to 820V, and the maximum limit value Umax of the bus voltage ranges from 850V to 880V.

5. The method for suppressing overvoltage control of a pitch motor controller according to claim 1, characterized in that: The calculation formula for the maximum limit value Pmax of the power generation power of the variable pitch motor is: Pmax=U*U / R5.

6. The method for suppressing overvoltage control of a pitch motor controller according to claim 1, characterized in that: The maximum torque limit Tlim max The calculation formula is: max =Pmax / omega.

7. The method for suppressing overvoltage control of a pitch motor controller according to claim 1, characterized in that: The bus voltage U is 800V, and the maximum limit value Umax of the bus voltage is in the range of 860-870V.

8. The method for suppressing overvoltage control of a pitch motor controller according to claim 7, characterized in that: The maximum limit value Pmax of the power generation power of the pitch motor is 32kw.

9. The method for suppressing overvoltage control of a pitch motor controller according to claim 1, characterized in that: A braking resistor (R5) and a MOS tube are connected in sequence between the output end of the filter module and the bus voltage between the inverter module; wherein a diode is connected in parallel between the braking resistor (R5) and the bus voltage.

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