Drive system for a switch and method for driving a switch

Abstract

Drive system (3) for a switch (17), said drive system (3) comprising a drive shaft (16) connecting the drive system (3) with the switch (17), a motor (12) for driving said drive shaft (16), and a feedback system (4) arranged for determining at least one value for the position of the drive shaft (16) and for generating a feedback signal on the basis of said at least one value, and a control device (2) arranged for influencing the operation of the motor (12) in dependence on the feedback signal.

Description

Technical Field

[0001] The present invention relates to a drive system for a switch and a method for driving a switch. Background Technology

[0002] Substations contain multiple switches for different tasks and with varying requirements. These switches must be operated via a drive system to function. These switches include, in particular, on-load tap changers, load switching switches, selectors, double commutators, commutators, preselectors, power switches, load switches, and circuit breakers.

[0003] Thus, on-load tap changers are used, for example, to make uninterrupted switching between different winding taps of electrical operating devices, such as power transformers or adjustable chokes. This can, for example, change the transformer's turns ratio or the choke's inductance. Dual commutators are used to switch the winding poles during power transformer operation.

[0004] All these switches are highly safety-related components of the operating electrical equipment. Switching occurs while the equipment is in operation and, consequently, connected to the power grid, for example. Disturbances during operation can have severe technical and economic consequences in extreme cases. Summary of the Invention

[0005] Therefore, the objective of this invention is to provide an improved scheme for driving switches, thereby enhancing operational safety.

[0006] The task is accomplished by a drive system for at least one switch according to the invention.

[0007] Another objective of the present invention is to provide a method for driving at least one switch, the method providing an improved scheme for driving the switch, thereby improving the flexibility of driving and the safety during switching.

[0008] The task is accomplished by a method according to the invention for driving at least one switch.

[0009] The improved solution is based on the concept of equipping the drive shaft used to drive the switch with a feedback system capable of detecting at least one value representing the position of the drive shaft. The feedback signal is generated based on this value, as it influences the operation of the motor.

[0010] According to the improved scheme, a drive system for a switch is provided. The drive system includes: a drive shaft connecting the drive system and the switch; a motor for driving the drive shaft; and a feedback system. The feedback system is configured to: determine at least one value for the position of the drive shaft, and generate a feedback signal based on the at least one value. Furthermore, the drive system includes a control device configured to act on the operation of the motor according to the feedback signal.

[0011] According to at least one embodiment, the switch may be configured as an on-load tap changer, a load switching switch, a selector, a double commutator, a commutator, a preselector, a power switch, a load switch, or a circuit breaker.

[0012] The term "value for the position of the drive shaft" also includes values ​​of measurement parameters such that the position of the drive shaft can be uniquely determined (within tolerances, if necessary).

[0013] By determining at least one value for the position of the drive shaft, the control device can improve the safety of position determination and reduce the corresponding residual risk of incorrect position determination.

[0014] According to at least one embodiment, the drive system is used to drive a switch, such as the shaft of an on-load tap changer or a corresponding component of an on-load tap changer. This causes the on-load tap changer to perform one or more operations, such as switching between two winding taps of a running device or portions of said switching, such as load switching, selector operation, preselector operation, or dual commutator operation.

[0015] According to at least one embodiment, the drive shaft is directly or indirectly, particularly via one or more transmission devices, connected to a switch, particularly the shaft of the switch.

[0016] According to at least one embodiment, the drive shaft is directly or indirectly, particularly via one or more transmission devices, connected to a load changer, selector, double commutator, commutator, power switch, load switch, or circuit breaker, particularly connected to the shaft of the load changer, selector, double commutator, commutator, power switch, load switch, or circuit breaker.

[0017] According to at least one embodiment, the drive shaft is directly or indirectly, particularly via one or more transmission devices, connected to a motor, particularly the motor shaft of the motor.

[0018] In at least one embodiment, the position, particularly the absolute position, of the motor shaft corresponds to the position, particularly the absolute position, of the drive shaft. That is, the position of the drive shaft can be uniquely inferred from the position of the motor shaft (within tolerance, if necessary).

[0019] According to at least one embodiment, the generating action includes open-loop control, closed-loop control, braking, acceleration, or stopping of the motor. Closed-loop control may include, for example, position control, speed control, acceleration control, or torque control. At least in the case of such closed-loop control, the drive system can be described as a servo drive system.

[0020] According to at least one embodiment, the drive system includes a monitoring unit configured to monitor, based on feedback signals, one or more operations of a switch, on-load tap changer, load switching switch, selector, double commutator, commutator, preselector, power switch, load switch, or circuit breaker. Monitoring specifically includes monitoring whether each operation or part thereof is performed in accordance with a predetermined schedule, particularly within a predefined time window.

[0021] According to at least one embodiment, the control device includes a control unit and a power supply element for powering the motor under open-loop or closed-loop control. The control unit is configured to drive the power element according to at least one rated value, particularly a position rated value, a speed rated value, or an acceleration rated value.

[0022] According to at least one embodiment, the power component is designed as a converter or servo converter or as an equivalent electronic unit for driving equipment, particularly a purely electronic unit.

[0023] Depending on the implementation, the control device may include a feedback system, either wholly or partially.

[0024] According to at least one embodiment, the feedback system is configured to obtain a first value for the position of the drive shaft according to a first method.

[0025] In at least one embodiment, the value for the position of the drive shaft is a value for the absolute position of the drive shaft.

[0026] According to at least one embodiment, the value for the position of the drive shaft is an incremental value for the position of the drive shaft or a value for the relative position of the drive shaft.

[0027] In at least one embodiment, the feedback system is configured to determine the rotor position of the motor and thereby determine a value for the position relative to the drive shaft based on the rotor position.

[0028] In at least one embodiment, the rotor position is an angular range in which the rotor of the motor is located, and the angular range is, if necessary, combined with the number of complete rotations of the rotor.

[0029] Based on the rotor design, particularly the number of pole pairs, the position or absolute position of the motor shaft can be precisely determined, except for at least 180° (e.g., via a control device). The achievable accuracy of the drive shaft position is significantly improved by means of speed reduction via one or more transmission devices. The evaluation performed via the control device here corresponds to, to some extent, the function of a virtual encoder. This combination is also known as a virtual rotary encoder.

[0030] According to at least one embodiment, the feedback system includes an encoder that is an absolute encoder and is configured to: detect the absolute position of a drive shaft or the absolute position of another shaft connected to the drive shaft, and generate at least one output signal based on the detected position. The feedback system is configured to determine, based on the at least one output signal, a value for the position of the drive shaft relative to the absolute position.

[0031] According to at least one embodiment, the encoder is directly or indirectly fixed to a motor shaft, drive shaft, or shaft coupled thereto.

[0032] According to at least one embodiment, the encoder has a first output terminal for outputting a first value for absolute position.

[0033] The term "encoder" includes not only means for obtaining two values ​​for a position in different ways, but also means for means that include two separate encoders, at least one of which is an absolute encoder.

[0034] According to at least one embodiment, the encoder includes an absolute encoder, a multi-turn rotary encoder, or a single-turn rotary encoder.

[0035] According to at least one embodiment, the encoder is configured to detect the position of the drive shaft or the position of the other shaft according to a first scanning method.

[0036] According to at least one embodiment, the scanning method includes optical, magnetic, capacitive, resistive, or inductive scanning methods.

[0037] In at least one embodiment, the encoder is engaged with a drive shaft, a motor shaft, or the other shaft.

[0038] According to at least one embodiment, the encoder is additionally force-locked or material-locked, for example by adhesive connection, to the drive shaft, motor shaft, or the other shaft.

[0039] The fixation of the encoder is further improved by form-locking connections and additional material-locking or force-locking connections, and ultimately operational safety is further enhanced.

[0040] In another embodiment, the feedback system is configured to: determine at least one value for the position of the drive shaft by means of an encoder and an auxiliary contact, and generate a feedback signal based on said at least one value. Here, the encoder and the auxiliary contact can each generate separate values, which are then combined into a single value to generate the feedback signal. Furthermore, the corresponding values ​​of the encoder and the corresponding values ​​of the auxiliary contact—which together reflect the position of the drive shaft—can directly generate a common feedback signal.

[0041] The drive system has a control device configured to act on the operation of the motor based on a feedback signal, which is based on a common value of the encoder and auxiliary contacts or on their respective individual values.

[0042] By determining two values—from which the position of the drive shaft is derived—the concept of this invention can be implemented in different hardware. Ultimately, this improves the operational safety of the drive system, switches, and operating devices.

[0043] According to at least one embodiment, the feedback system is configured to obtain a first value via an encoder according to a first method and at least a second value via an auxiliary contact according to a second method. The values ​​are then combined into a single value.

[0044] The methods described can be distinguished by different technical or physical principles or different components (hardware components).

[0045] According to at least one embodiment, the first value of the encoder's position relative to the drive shaft is a first value of the absolute position relative to the drive shaft.

[0046] According to at least one embodiment, the second value of the auxiliary contact relative to the drive shaft is a second value of the relative position of the auxiliary contact relative to the drive shaft.

[0047] The first value and the second value form the absolute position of the drive shaft.

[0048] In at least one embodiment, the feedback system is configured to determine the rotor position of the motor and, based on the rotor position, determine one of at least two values ​​for the position relative to the drive shaft. Here, the feedback system has an encoder, which is a so-called virtual rotary encoder.

[0049] According to at least one embodiment, the feedback system includes an encoder and an auxiliary contact, the encoder and the auxiliary contact being configured and set to detect, in combination, the absolute position of the drive shaft or the absolute position of another shaft connected to the drive shaft and generate at least one output signal based on the detected position.

[0050] According to at least one embodiment, the encoder and the auxiliary contact are directly or indirectly fixed to the motor shaft, drive shaft, or shaft coupled thereto.

[0051] According to at least one embodiment, the encoder has a first output terminal for outputting a first value, and the auxiliary contact has a second output terminal for outputting a second value, wherein each of the values ​​forms the absolute position of the drive shaft.

[0052] In at least one embodiment, the auxiliary contact is configured to additionally detect the position of the drive shaft or the position of the other shaft according to the scanning method.

[0053] According to at least one embodiment, the scanning method includes mechanical, optical, magnetic, capacitive, resistive, or inductive scanning methods.

[0054] According to at least one embodiment, the auxiliary contact is additionally force-locked or material-locked, for example by adhesive connection, to the drive shaft, motor shaft, or the other shaft.

[0055] By using form-locking connections and additional material-locking or force-locking connections, the operational safety is further improved by fixing the auxiliary contacts.

[0056] According to the improved scheme, a method for driving an on-load tap changer is also provided. The method includes: determining at least one value of the absolute position of a drive shaft for driving the on-load tap changer; generating a feedback signal based on the at least one value; and controlling a motor for driving the on-load tap changer according to the feedback signal.

[0057] Other design forms and implementations of the method are directly derived from different design forms of the tap changer. In particular, one or more of the components and / or arrangements described with respect to the tap changer can be implemented accordingly to carry out the method. Attached Figure Description

[0058] The invention will now be described in detail with reference to the accompanying drawings and exemplary embodiments. Identical, functionally identical, or effect-equivalent components may be provided with the same reference numerals. Identical or functionally identical components may be described with reference only to the drawings in which they first appear. The description is not necessarily repeated in subsequent drawings.

[0059] In the picture:

[0060] Figure 1 A schematic diagram illustrating an exemplary implementation of a drive system according to an improved scheme; and

[0061] Figure 2 A schematic diagram illustrating another exemplary implementation of the drive system according to the improved scheme is shown. Detailed Implementation

[0062] The same reference numerals are used for the same or equivalent elements in this invention. Furthermore, for clarity, only the reference numerals necessary for illustrating the respective figures are shown in the individual figures. The figures merely illustrate embodiments of the invention; however, the invention is not limited to the illustrated embodiments.

[0063] Figure 1 A schematic diagram illustrating an exemplary embodiment of a drive system 3 for switch 1 is shown. The drive system 3 is connected to switch 1 via a drive shaft 16. The drive system 3 includes a motor 12, which can drive the drive shaft 16 via a motor shaft 14 and optionally via a transmission 15. The control unit 2 of the drive system 3 includes: a power element 11, which includes, for example, a converter (not shown) for powering the motor 12 under open-loop or closed-loop control; and a control unit 10 for driving, for example, the power element 11 via a bus 18. The drive system 3 has an encoder 13, which serves as a feedback system 4 or is part of a feedback system 4 and is connected to the power element 11. Furthermore, the encoder 13 is directly or indirectly coupled to the drive shaft 16.

[0064] Encoder 13 is configured to detect at least one first value relating to the position of drive shaft 16, particularly angular position, such as absolute angular position. For this purpose, encoder 13 may include, for example, an absolute encoder, particularly a multi-turn absolute encoder, fixed to drive shaft 16, motor shaft 14, or another shaft whose position is uniquely associated with the absolute position of drive shaft 16. For example, the position of drive shaft 16 may be uniquely determined by the position of motor shaft 14, for example, via the transmission ratio of a drivetrain.

[0065] Feedback system 4 is configured to detect the position value for drive shaft 16.

[0066] The control device 2, particularly the control unit 10 and / or the power unit 11, is configured to control the motor 12 in an open-loop or closed-loop manner based on a feedback signal, and the feedback system 4 generates the feedback signal based on the value.

[0067] Figure 2Another schematic diagram illustrating an exemplary embodiment of the drive system 3 is shown. Here, an auxiliary contact 9 may be attached to the encoder 13, which may be configured as an absolute encoder, a multi-turn absolute encoder, a single-turn absolute encoder, a single-turn rotary encoder, an incremental encoder, or a virtual rotary encoder. The drive system 3 thus has an encoder 13 and an auxiliary contact 9, which serve as a feedback system 4 or are part of a feedback system 4 and are connected to the power unit 11.

[0068] The auxiliary contact 9 can be configured as at least one microswitch, resolver, or sine-cosine encoder. The position of the drive shaft 16 can be uniquely determined by means of the encoder 13 in conjunction with the auxiliary contact 9.

[0069] Alternatively or additionally, the control device 2 may be configured to determine the position value of the drive shaft 16 from the rotor position of the motor 12. This relates to the encoder 13, which has already been described as a virtual rotary encoder.

[0070] Furthermore, the induced feedback can be fully utilized, for example, by the movement of the rotor in the motor windings of motor 12. Because the intensity of the feedback varies periodically, the rotor position can be approximately determined, particularly by means of signal analysis, such as Fast Fourier Transform (FFT) analysis. Since one complete rotation of drive shaft 16 corresponds to multiple rotations of the rotor, the position of drive shaft 16 can thus be inferred with much higher accuracy. Additionally, auxiliary contact 9 can supplement the determination of the position of drive shaft 16.

[0071] Control device 2, particularly control unit 10 and / or power unit 11, is configured for open-loop or closed-loop control of motor 12 based on a feedback signal, wherein feedback system 4 generates the feedback signal based on the first value. According to the design, the value is generated via the output signal of encoder 13 or via the output signal of encoder 13 combined with auxiliary switch 9.

[0072] List of reference numerals in the attached diagram:

[0073] 1 switch

[0074] 2 Control device

[0075] 3 drive system

[0076] 4 Feedback System

[0077] 9 auxiliary contacts

[0078] 10 control units

[0079] 11 power components

[0080] 12 motors

[0081] 13 encoders

[0082] 14 motor shafts

[0083] 15 Transmission Device

[0084] 16 drive shafts

[0085] 18-bus

Claims

1. A drive system (3) for a switch (17), the drive system (3) comprising: - Drive shaft (16), which connects the drive system (3) and the switch (17); - Motor (12), the motor being used to drive the drive shaft (16); and - Feedback system (4), the feedback system being configured to: determine at least one value for the position of the drive shaft (16); and generate a feedback signal based on the at least one value; and - Control device (2), the control device being configured to act on the operation of the motor (12) according to the feedback signal, in, The feedback system (4) includes at least one encoder (13), characterized in that the encoder is configured as a single-turn rotary encoder, and the feedback system includes an auxiliary contact (9), the at least one encoder and the auxiliary contact being configured together for: detecting the absolute position of the drive shaft (16) or the absolute position of another shaft connected to the drive shaft (16), and generating at least one first output signal based on the detected position; and the feedback system being configured for determining a value of the position for the drive shaft (16) based on the at least first output signal.

2. The drive system (3) according to claim 1, wherein, The value for the position of the drive shaft (16) is the value for the absolute position of the drive shaft (16).

3. The drive system (3) according to claim 1 or 2, wherein, The auxiliary contact (9) is implemented as at least one microswitch or resolver.

4. The drive system (3) according to claim 1 or 2, wherein, The switch (17) is an on-load tap changer or load switching switch or load selector or selector or commutator or double commutator or preselector or power switch or load switch or circuit breaker.

5. A method for driving a switch (17) by means of a drive system (3) according to any one of claims 1 to 4, the method comprising: - Determine at least one value for the absolute position of the drive shaft (16) used to drive the switch (17); - Generate a feedback signal based on at least one of the values; as well as - The motor (12) used to drive the switch (17) is controlled according to the feedback signal.

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