DE102014114787A1 - Pitch motor drive circuit for a wind or hydroelectric power plant and associated operating method - Google Patents

Abstract

The invention relates to a pitch motor drive circuit (40, 42, 44, 46, 48, 98) for a wind or hydro power plant (100) comprising at least one motor inverter device (52) associated with a pitch motor (28), the motor inverter device (52) comprises a chargeable emergency power supply (56). It is proposed that the at least one motor converter device (52) is preceded by at least one charging converter device (50) connected to a supply network PG (12), wherein the charging converter device (50) is set up, the motor converter device (52) having a multi-phase, in particular three-phase local network (54). Furthermore, an operating method for such a pitch motor drive circuit (40, 42, 44, 46, 48, 98) is proposed, wherein depending on a charging current and / or a state of charge of at least one in an emergency power supply device (58) included energy storage an amplitude height, voltage waveform and / or frequency of the local area network (54) of the charge converter device (50).

Description

The present invention relates to a pitch motor drive circuit for adjusting the angle of attack of one or more rotor blades of a wind or hydroelectric power plant and an associated operating method. In particular, the invention relates to a pitch motor drive circuit with a high capacity, rechargeable emergency power supply that has the ability to tolerate overvoltages and undervoltages of the grid.

STATE OF THE ART

Various pitch motor drive circuits for wind or hydroelectric plants are known from the prior art, which are known in particular by emergency running properties, for example in case of mains voltage failure, damage to control components or under or over voltage of the network.

Generic pitch drives are used to adjust the angle of attack (pitch) of a rotor or turbine blade against a Anströmmedium such as wind or water. Due to the high forces acting on a rotor or turbine blade, electric three-phase motors are used for the adjustment in the rule, which are supplied via a converter device with a variable rotational frequency and amplitude in order to provide different speeds and torques can. A converter device generally comprises a rectifier device, which provides a DC voltage from a network-side alternating or three-phase voltage and feeds it into a DC intermediate circuit. From the DC voltage using an inverter device variable in frequency and amplitude alternating or rotating voltage is generated, which is supplied to the three-phase motor. So is schematic in 1 a wind turbine with such pitch motors shown, wherein in 2 a drive circuit known from the prior art is described.

The circuit of rectifier device, DC voltage intermediate circuit and inverter device is referred to below as a converter device. An inverter device comprises a plurality of electronic power semiconductor switches and generally has three half-bridges, which are equipped with MOSFET, IGBT or IGCT transistors. As a rule, these are two-stage half-bridges, which, however, can also be designed in three stages or in several stages in order to be able to supply variable output voltages. By a pulse width modulation of the switching behavior of the semiconductor switching components variable frequencies, phases and amplitudes can be controlled in a wide range to drive asynchronous or synchronous AC or three-phase pitch motors.

To increase reliability and to ensure safety travel in the event of a power failure, pitch drive circuits may comprise an emergency power supply device, for example batteries or accumulators or high-power capacitors, in particular so-called supercaps for storing electrical energy for an emergency operation. Supercapacitors, also referred to as ultracapacitors, have an extremely high electrical storage capacity, bridging a gap between capacitors and accumulators. They can achieve capacitance values of 10 kilofarads per 1.2 volts and have capacitance values that can be 10,000 times greater than conventional electrolytic capacitors. To charge high-capacity capacitors, accumulators or supercaps, it is necessary to provide a sophisticated charging electronics, which can provide a controllable DC voltage and a regulated charging current available. The aim is to keep the AC component in the charging current as low as possible. Therefore, simple circuit designs based on B6 bridges or Thyristorladeschaltungen rather unsuitable. Particularly in the case of greatly varying voltage conditions in a supply network, as occurs in the environment of regenerative energy generation systems, it is technically difficult to realize a component-saving and short charging operation.

From the prior art, there is thus the problem of providing a robust drive circuit and a corresponding operating method for pitch motors, which can ensure safe operation of a wind or hydroelectric power plant both in the case of line-side undervoltage and overvoltage. In particular, the possibility of low voltage ride through (LVRT) operation and high voltage ride through (HVRT) operation, i. interference-free operation in case of grid under- and overvoltage is problematic in volatile supply networks with a variety of regenerative energy sources. In addition, there is the problem of providing a reliable and high-quality charging method for high-capacity emergency power supply devices that ensures safe charging and long-term operation with reliable emergency operation even in adverse conditions.

Based on the aforementioned disadvantages, it is therefore an object of the invention to overcome the disadvantages known from the prior art.

This object is achieved by a pitch motor drive circuit and an operating method according to the independent claims. Advantageous developments of the invention are the subject of the dependent claims.

DISCLOSURE OF THE INVENTION

According to the invention, a pitch motor drive circuit for a wind or hydropower plant is proposed which comprises at least one pitch motor associated with a motor converter device comprising a rectifier device, an inverter device and a DC intermediate circuit in the interposed charging rechargeable emergency power supply device. The at least one motor converter device is connected upstream of at least one load converter device connected to a supply network, wherein the load converter device is set up to supply the motor converter device with a local network. The local area network can be single-phase or multi-phase.

In other words, a series connection of two converter devices between a supply network and a pitch motor is proposed, wherein a local network is provided between the first converter device and the second motor converter device, which is supplied by the converter device and to the needs of the motor converter device, in particular a charging operation for the latter contained emergency operation device can be adjusted. This ensures that the network can be decoupled from the local area network with too low or too high a voltage, or a controllable local area network can be provided independently of the voltage and frequency level of the supply network to optimally supply the motor converter device and in particular a charging mode of the emergency operating device can provide. In particular, supercapacitors or double-layer capacitors must be charged in a controlled way, with high charging times being required for high capacitances and large charging currents. Suitable chargers are relatively expensive and expensive and are usually centrally installed, for example, in a nacelle or in a rotating hub of a wind or hydro power plant to independently supply three or more pitch motor inverter devices. A central charging converter device, which can be connected upstream of the individual motor converter devices, makes it possible to dispense with separate chargers, whereby large charging currents can be provided without problems even under varying network conditions. In order to improve the charging current quality, the charging converter device and the provided local network can be optimally adjusted to be able to provide an optimized charging current during charging phases of the emergency operating devices.

In an advantageous development, a single charging device is provided, which provides the local area network for all engine conversion devices of the wind or hydroelectric power plants. As a result, a single, high-performance, load converter device can centrally provide the electrical energy for all pitch motor inverter devices. Alternatively, it is also conceivable to associate a separate charging converter device, in particular a structurally identical charging converter device, with each motor converter device. For this purpose, advantageously and component-saving the central or each motor converter device upstream Ladeumrichtervorrichtung depending on the operating mode pitch operation or charging operation and depending on the state of charge provide different frequencies and voltages in the local network or in the various pitchmotorbezogene local networks.

Basically, the loader device provides a local area network that may have a network synchronous frequency. In an advantageous embodiment, the charging converter device can be set up to operate a local area network with a frequency greater than the network frequency of the supply network, in particular with 400 Hz or a higher frequency. By increasing the local network frequency by atypical higher values of 400 Hz or more, charging current ripple can be reduced and thus, especially in charging operation, charging of emergency power supply devices comprising double-layer capacitors or supercaps can be gently charged. As a result, a longevity is achieved and the storage capacity of the emergency operation power supply device is maintained. The provision of an AC network as a local area network also offers advantages in the selection of necessary system components, e.g. Fuses and contactors in comparison to a DC power supply.

In an advantageous development, a control device of the at least one charging converter device can be set up to receive charge current control information of the emergency power supply device, in particular charge current and / or charge state of an energy store included in the emergency power supply device, in particular an integrated double-layer capacitor or supercap energy store, and can furthermore be set up, to use this control information to control the amplitude level, waveform shape and / or frequency of the local area network. In this development, it is proposed that a control device controlling the charging converter device, in particular a Control device that provides switching signals for the inverter device of the charging converter device, receives control information of the emergency operating device. In particular, these control information can characterize a charging current or charging state or a charging voltage of the emergency operating device, in particular an electrical state of an energy store contained therein. This makes it possible to individually adapt voltage and frequency, in particular amplitude height and amplitude shape of the local area network, to a charging cycle in order to provide an optimized charging current in charging phases in which the emergency operating facilities are charged and to ensure a gentle charging of the energy stores contained therein. As a result, an optimized charging current can be provided, whereby the energy efficiency and the longevity of the emergency operating device can be improved.

Advantageously, at least one charging converter device can be arranged in the stationary part of the wind or hydropower plant, in particular in a nacelle, and the motor converter device can be arranged in the rotating part, in particular in the rotor hub, in the pitch motor drive circuit. As a result, the limited space of the rotor hub can be used elsewhere and arranged a relatively powerful charger converter device in the stationary part, in particular in a nacelle or in the stationary part of a hydropower plant.

Furthermore, control information from the motor converter device, in particular the emergency operating energy storage device to the charging converter device contained therein, and vice versa may be transferable via an information transfer device, in particular via a slip ring contact device from the rotating to the stationary part of the power plant. The charging current control information can for example be taken directly via voltage and current sensors, but can also be derived indirectly, such as the behavior of the motor converter control device. Control information must be transmitted from a rotating part, namely from the pitch motor inverter devices, to a stationary part, namely the nacelle or to a stationary external area of the wind or hydro plant, to provide an optimized state of the local area network. This control information can be transmitted wirelessly such as wireless or Bluetooth or wired, for example via additional slip rings a slip ring contact device, for example. In particular, it is also possible to transmit information signals, for example in the form of modulated data signals of a carrier frequency system such as Powerline or the like, via the existing power slip ring contact devices which are provided for current transmission of the operating energy of the pitch motor. By modulating data information, for example on the state of charge, charging voltage or charging current of the emergency operating power supply via the supply energy transferring slip rings between rotor hub and stationary part can be set up without additional wiring effort optimized behavior of the charger assembly to the operating condition of the motor drive device. As a result, cabling is saved. In addition, parameters, control values and actual values between the inverter and a higher-level control device can be exchanged via this communication channel.

In a further advantageous embodiment, a filter device can be arranged between the charging converter device and the motor converter device. The filter device may comprise capacitors and inductors and may filter or smooth current ripple or high-frequency pulse components of the local area network in order to be able to provide as uniform as possible a charging current with a low harmonic content for charging the emergency operation power supply device.

In an advantageous development, a voltage adjustment device, in particular a transformer device or a phase control device, can be arranged between the charging converter device and the motor converter device and / or between the supply network and the charging converter device. By means of a transformer or a phase control either between the supply network and charger converter device and / or between charger and motor device in the local network voltage differences can be compensated in particular, so voltage levels are increased or decreased and dynamically effective voltage levels are adapted for example in phase control devices to the motor inverter devices optimally with a constant operating voltage to supply. The operating voltage can thus be varied in the motor converter device depending on the active pitch operation or charging operation, and a higher or a lower local network frequency and / or a higher and / or lower voltage level can be provided. In particular, this increases the HVRT / LVRT capability of the pitch drive. The amplitude of the voltage islands of the local area network can be limited by the charging converter device, so that the motor converter devices are protected against overvoltage. Also, the charger converter device can be protected from over or under voltage by an upstream transformer or a phase control. Advantageously, the aforesaid transformer means may comprise a Yyd or Dyd transformer using, for example, B12 rectification with a transformer having two secondary windings to minimize network perturbations.

In an advantageous development, at least one of the motor converter devices and / or the at least one charging converter device may comprise an active rectifier device or a phase control device. An active rectifier is an inverter device that can be controlled so that it can produce a DC voltage from an AC voltage, thus being reciprocally adapted to normal operation of an inverter. By means of a phase angle control device, amplitude components can be controllably cut out of a change or three-phase current in order to provide a rectification, wherein an adjustment of the level of the DC voltage and the harmonic distortion can be achieved. Thus, the use of passive diodes can be dispensed with, and an improved and adaptive DC power supply can be provided.

In an advantageous development, the at least one charging converter device and / or at least one motor converter device can be bridged by a bridging switching device. By means of a bridging switching device, for example, the charging converter device can be switched out of the pitch motor drive circuit or a motor converter device can be bridged. This can be advantageous, in particular in the event of a fault, since, for example, if a motor converter device fails, the charging converter device can take over its function and control the pitch motor. Likewise, if the charging converter device is damaged, the motor converter devices can be connected directly to the supply network, so that a redundant design and thus an increased robustness of the drive circuit against errors and breakdown can be achieved.

Advantageously, at least two charging converter devices can be included, wherein by means of a switching matrix which comprises a plurality of clutch switching devices, at least one charging converter device can be connectable to each motor converter device. The presence of two or more power converter devices associated with one or a group of motor drive devices and a switching matrix that enables the power converter devices to be connected in parallel or independently to different motor drive devices increases redundancy and further reduces the probability of failure of the drive circuit in order to achieve a robust and long-lasting operation of the drive circuit.

The formed local area network between the charging converter device and the motor converter device can be grounded or groundless. If it is operated without earth as a so-called IT network, the local area network can advantageously be monitored by an insulation monitoring device for insulation faults, which is preferably arranged in or downstream of the charging converter device. The IT network has good EMC characteristics and, in addition, a simple ground fault does not result in immediate disconnection of the network in this network. In particular, when using a secondary-side transformer in the local area network, the secondary side can be monitored by an insulation monitoring device. An IT network is fail-safe, so that no failure of the drive circuit occurs in a single ground fault. Thus, a further operation can be guaranteed in an insulation fault first. The insulation monitoring device makes it possible to detect earth faults in the local network early and to indicate insulation faults before a failure of the control circuit takes place. The IT network has much higher reliability than other TN or TT networks. In terms of security of supply, IT systems offer the most advantages of all network forms.

In a sidelined aspect, the invention proposes an operating method for the pitch motor drive circuit, wherein, depending on the charging current and / or the state of charge of at least one energy store included in an emergency operating device, an amplitude level, voltage waveform and / or frequency of the local network of the charging converter device, in particular for smoothing harmonics is set. Thus, the charging converter device is controlled such that it outputs a voltage in the local area network whose amplitude level, whose voltage profile and / or frequency depends on an active pitch operation or a charging operation of the emergency operating device in the motor converter device. Thus, in deep-discharged emergency operation facilities, a higher amplitude and possibly a high harmonic content in the local area network can be provided, while low harmonics and a low local network voltage can be applied to a fully charged or uploaded emergency operation facility. Thus, optimized for the state of charge, the local network voltage of the charger device can be adjusted.

For example, in the case of a decreasing state of charge, advantageously a trapezoidal amplitude characteristic of the charging voltage can be selected, so that a predetermined maximum permissible Charging current is not exceeded. Accordingly, the maximum amplitude of the charger for the local area network can be selected at 100% of the maximum amplitude in the case of a low state of charge, while only 70% of the maximum amplitude in the local area network is input when the state of charge is increased. As a result, depending on the state of charge of the emergency power supply device, a different voltage waveform, frequency and voltage level is used for the local area network in order to achieve an optimized charging speed and energy efficiency.

In particular, it is the task of the operating method to set the charging current so that harmonics can be smoothed in order to be able to set an optimized charging current. By using a phase control or IGBT inverter for rectification, i. an active rectifier device, in particular overvoltages of the network can be compensated so that a HVRT / LVRT operation of the pitch drive circuit is made possible.

The charging converter device can be designed as an active front end and, in a central arrangement, can supply all pitch motor converter devices together with supply voltage in an optimal local network, so that a voltage supply optimized for the applications can be ensured both in active pitch mode and in charging mode.

DRAWINGS

Further advantages result from the present description of the drawing. In the drawings, embodiments of the invention are shown. The drawing, the description and the claims contain numerous features in combination. The person skilled in the art will expediently also consider the features individually and combine them into meaningful further combinations.

Show it:

1 a wind turbine with pitch-controlled rotor blades;

2 a pitch motor drive circuit of the prior art;

3 A first embodiment of a drive circuit according to the invention,

4 a further embodiment of a drive circuit according to the invention;

5 another example of a drive circuit according to the invention;

6 two examples of drive circuits according to the invention;

7 another example of a drive circuit according to the invention;

8th a further embodiment of a drive circuit according to the invention;

9 a further embodiment of a drive circuit according to the invention.

10 a combination of transformer and rectifier means for optimally providing a DC voltage for an embodiment of the invention;

11 an embodiment of an inverter device with active rectifier device for use in an embodiment of the invention;

12 an amplitude waveform for a local power voltage at low state of charge for an embodiment of the invention.

In the figures, the same or similar components are numbered with the same reference numerals.

The 1 shows a wind turbine 100 in which a gondola 104 on a mast 102 rests. In the gondola 104 is a rotor hub 106 introduced, on the three rotor blades 108 are arranged. For adjusting an angle of attack of the rotor blades 108 opposite to the wind are pitch adjusters 110 provided at the transition between rotor hub 106 and rotor blade 108 attached, and a pitch angle 116 can adjust. Especially in heavy weather such as storms, thunderstorms, snowfall or hail the wind turbine is exposed to harsh environmental conditions, with violent wind changes can take place. As a rule, the increased incidence of regenerative energies causes strong voltage fluctuations in the supply network, so that the pitch actuators are driven 110 a robust drive circuit is provided.

In the 2 is a pitch motor drive circuit known in the art 10 shown. On a three-phase supply network PG 12 is a converter device 14 connected to a three-phase pitch motor 28 supplied with electrical energy. The pitch motor 28 drives over a pitch drive shaft 114 and a pitch gear 112 a pitch adjustment device 110 on, which is a rotor blade 106 in their pitch angle 116 adjusted against the incoming wind. This allows the speed and power of the wind turbine 100 adapt to different wind conditions. For electrical supply of the three motor strings 30 of pitch motor 28 become the three phases of the supply network 12 via a rectifier device 16 in a DC link 34 rectified. The rectifier device 16 includes six rectifier diodes 22 which are arranged in a bridge circuit. In the DC link 34 is a DC smoothing device 20 used in the form of a capacitor, which can also form an emergency operation supply device with a correspondingly high capacity, and, for example, a short-term maintenance of the intermediate circuit voltage allows in case of power failure, so that the pitch angle 116 can be adjusted so that a safe flag setting of the rotor blade 108 is reached, thus the wind turbine 100 to put out of service. The DC voltage of the DC link 34 is in an inverter device 18 by means of a bridge circuit of six IGBT inverter switching elements 24 converted into a three-phase voltage of variable frequency and amplitude. Every IGBT 24 is a freewheeling diode 26 connected in parallel, which allows a directed current flow through the inverter half-bridge. By a control device, not shown, the switching frequency of the inverter device 18 be changed to a variable frequency and voltage level of the supply voltage for the supply phases 32 of the pitch motor 28 To set, thus different speeds and torques of the pitch motor 28 to be able to provide.

In the illustrated drive circuit 10 The prior art has the disadvantage that variable supply voltages of the network PG 12 have a direct influence on the level of DC link voltage, and a directed charging current for the emergency power supply 20 can not be guaranteed. In particular, high-capacitance capacitor arrangements or supercaps can be used in such a drive circuit 10 do not integrate, since a necessary charge control causes a high circuit complexity and therefore high costs.

In the 3 is a first embodiment of a drive circuit 40 shown. A charging converter device 50 is three-phase with a supply network PG 12 connected. The charging converter device 50 includes a rectifier device 16 using a bridge rectifier with passive diodes 22 includes. The rectifier device 16 provides a DC link 34 available for smoothing a DC smoothing device 20 having. At the DC link 34 is an inverter device 16 connected with three inverter bridges, each containing IGBT switching elements 24 with freewheeling diodes 26 a three-phase local network 54 supply. The charging converter device 50 serves to the voltage and frequency variable local network 54 to power to the three motor inverter devices 52 for controllable operation of three pitch motors 28 are arranged. Each motor inverter device 52 in turn comprises a DC intermediate circuit, which via a charge controller, not shown, with a high-capacity emergency power supply device 56 connected is. In case of failure of the charging converter device 50 or a failure of the supply network 12 can the emergency power supply 56 at least in the short term the motor converter device 52 provide energy to the respective pitch drive 28 to move into a flag position. The for charging the emergency operation device 56 required electrical energy is transmitted through the local area network 54 provided, wherein the Ladeumrichtervorrichtung 50 for active pitch operation and for charging operation different voltages and frequencies in the local area network 54 can provide.

In the 4 is another embodiment 42 a drive circuit shown. As a progression to the in 3 illustrated embodiment 40 indicates the charger converter device 50 a connected charging converter control device 60 on. The control device 60 can voltage waveform, frequency and maximum amplitude of the local network 54 fed energy of the charger converter device 50 influence. The charge converter control device 60 is with charging current sensor devices 58 connected to a state of charge or charging current between the Motorumrichtervorrichtungen 52 and the emergency service facilities 56 can measure. Depending on the charging current, the voltage in the local network 54 to be controlled. To reduce harmonics and switching frequency signal components is a filter device 70 the load converter device 50 downstream, dampen the harmonics and a sinusoidal course of the local network 54 provides. For voltage adjustment, a transformer 76 in the local network 54 be on to the voltage in the local area network 54 to a target voltage of the motor converter devices 52 adapt.

An advancement of in 4 shown drive circuit 42 is as a drive circuit 44 in 5 shown. Here is the charger converter 50 , the filter device 70 with filter choke 72 and filter capacity 74 and a transformer device 76 in a gondola 104 a wind turbine 100 , ie arranged in a stationary part of the energy system. Via a slip ring contact device 62 Electricity is transmitted through three phases of the local network 54 in the rotating part, ie in the rotor hub 106 transferred to electrical energy for the motor inverter devices 52 provide. To control frequency, amplitude shape and phase in local area network 54 are charging current control devices 58 , which may be, for example, current and voltage measuring devices or indirectly by the control behavior of the motor converter devices 52 the charging current and the charging capacity of the low-power supply device 56 determine via an information transfer device 64 with the slip ring contact devices 62 connected. The information transmission device 64 may be a powerline connection that provides an information frequency signal via the slip ring contactor 62 in the dormant part of the power plant 100 transfers. In the dormant part is a powerline coupling device 68 , by the information signals from the pitch drive power supply of the local area network 54 extracted and the control device 60 be supplied. Thus, with no additional cabling overhead, carrier information can be transmitted via a grinder 62 Control information of the load converter device 50 the emergency power supply 56 monorized or bidirectionally transmitted to the local area network 54 depending on the operating state, and to control the inverters and / or to monitor.

In the embodiments of the 6a and 6b of drive circuits according to the invention 46 are between loader device 50 and supply network PG 12 a voltage adjustment device in the form of a transformer device 76 in 6a and in the form of a phase control device 36 in 6b shown. The transformer device 76 allows a fixed adjustment of the voltage level of the supply network 12 to the input of the charger converter device 50 , An adaptive voltage adjustment can be achieved by a phase angle control device 36 in particular to enable a low / high voltage ride-through operation. Thus, in the case of overvoltage, the phase control device 36 allow the voltage level to be lowered to the load converter device 50 to protect against overvoltage.

In a further embodiment in 7 that of the embodiment in 3 are for adaptive shutdown of the load converter device 50 or the motor inverter devices 52 parallel switching elements 78 provided as a bridging switching devices, by the example, a switching off in case of failure of a converter device 50 . 52 can be performed to high redundancy and emergency operation safety of the drive circuit 46 to ensure. Thus, in case of failure of the central converter device 50 these are bridged, and one in 2 shown drive circuit 10 form the state of the art. In case of failure of a single motor inverter device 52 can be a selective operation of the affected pitch motor 28 through the charge converter device 50 to be provided.

The local area network 54 can be designed as an IT network without grounding, with an insulation monitoring device 118 monitor the insulation conditions of the phases with respect to conductive parts, with the conclusion of a single phase, first, a further operation is possible. Only when two phases have a ground fault, there would be a failure of the drive circuit. As a result, a reduction in the susceptibility to errors and a higher robustness of the drive circuit 46 guaranteed.

In a further embodiment 48 in 8th is every engine converter device 52 a separate charger converter device 50 upstream. Through a switching matrix, consisting of coupling switching devices K312, K313 and K323 80 can be virtually any charger device 50 with every motor converter device 52 be connected at will, so that in case of failure of one or two Ladeumrichtervorrichtungen 50 another operation of a motor converter device 52 can be guaranteed. Furthermore, each converter device 50 . 52 a lock-up switching device 78 connected in parallel, so that a motor converter device 52 and / or a load converter device 52 can be bridged and thus another operation of the pitch motor 28 through the respectively further upstream charger converter / motor converter device 50 . 52 can guarantee. Thus, the highest possible redundancy and freedom of choice in the operation of the drive circuit is given, so that a high degree of robustness and longevity can be achieved. Advantageously, the motor and charger converter device 50 . 52 constructed identically, so that many Gleichbaugruppen can be used.

In the 9 is another embodiment 98 a drive circuit according to the invention shown. This can in normal operation according to the prior art, the respective pitch motors 28 by motor inverter devices 52 drive. In a charging mode in which no drive of the pitch motors 28 can be performed by a switching matrix comprising feedback switching devices 94 every motor converter device 52 as a load converter device 50 for another motor inverter device 52 serve, and so a controlled charging of a in the motor converter device 52 integrated emergency power supply device 56 provide. Thus, at least two out of three emergency power supply facilities 56 simultaneously by a reverse operation of a motor converter device 52 to be charged. This will be done with only three inverter devices 52 achieved the inventive advantages, usually no simultaneous pitching and loading operation can take place. For activation against the supply network 12 are network disconnection devices 96 for uncoupling the respective motor converter devices to be charged 52 intended. Furthermore, the respective pitch motors are in charge mode 28 as the loader device 50 serving engine converter device 52 from the inverter device 52 uncoupled, which means by means of motor decoupling switching device 92 is reached.

It is quite conceivable, individual features of the embodiments of drive circuits of 3 to 9 to combine to achieve advantageous developments of the invention.

In the 10 is a B12 rectifier 88 shown a Y transformer 88 includes the six-phase 12p rectifier device 90 fed. The YΔ transformer 88 includes two sets of transformer coils, one connected in delta and one star. The 12p rectifier device 90 includes two bridge rectifier circuits, wherein a bridge rectifier circuit rectifies the phases of the star transformer circuit and a bridge rectifier circuit rectifies the phases of the triangular transformer coils. With this, a three-phase current can be converted into a high-quality DC voltage with low harmonics in order to obtain a charging voltage for a high-capacitance emergency power supply 56 to be able to provide. A B12 rectifier 88 can be used advantageously in an embodiment of the invention for providing a DC link and charging voltage.

In the 11 is an AFE inverter device 82 shown (active front end), which is an active rectifier device 84 , a DC link 34 and an inverter device 16 includes. The rectifier device 84 is identical to an inverter device 16 built up. The AFE inverter device 82 Can be used both as a charger converter 50 as well as a motor converter device 52 be used. The active rectifier device 84 Alternatively, it may comprise a phase control device in order to be able to set a variable level of the intermediate circuit voltage.

Finally shows 12 a trapezoidal voltage waveform of a three-phase local network 54 , Wherein each offset by 120 ° phases U, V, W can provide a trapezoidal shape and thus a continuous maximum voltage. This will provide a maximum power delivery to a local area network 54 allows a high charging current, especially at low state of charge, the emergency operation power supply device 56 to be able to provide.

The individual switching devices 80 . 92 . 94 in the 7 . 8th and 9 are individually switchable and can be interconnected independently of each other in a wide variety of switching positions. They can be designed as mechanical switching relays, but also as electronic power switching elements, and are generally formed in three phases.

If the charging converter device is arranged centrally in a nacelle or in the stationary part of a power generation plant, the environmental conditions such as thermal stress or mechanical stress of the charging converter device are reduced. An information transfer, for example, the state of charge, via the slip ring contact device 62 be made possible for example by a carrier frequency transmission. A phase gating controller or transformer device in front of the load converter device may achieve adaptation to a varying supply network voltage. If a transformer device or a phase control is provided between the charger in the local area network and in front of the motor converter devices, the local mains voltage can be set to a suitable charging voltage of the emergency operating device in the charging mode, and the charging device can achieve efficient and gentle charging with low currents and reduced electrical losses. By using an increased frequency in the local area network, a transformer can be made structurally small. When a transformer device is used in front of the load converter device, a B12 transformer and a 6p rectifier device are available to minimize network feedback. An insulation monitoring device can advantageously be integrated in the charging converter device in order to be able to monitor a floating local network. For a carrier frequency information transmission, a carrier frequency standard of relatively low data rate may be used, for example, the information transmission of a state of charge of a single motor conversion device may be transmitted through one phase of the local area network. By using a choke coil, the charging of an emergency operating device can be further improved because the AC component can be reduced. The load converter device may be implemented as a block-commented regenerative active front-end to enable the energy exchange between the inverter devices. As an alternative to a variable voltage in the local area network, the voltage in the local area network can also be fixed and the charging current can be set via a controlled input rectifier device in the motor converter device.

LIST OF REFERENCE NUMBERS

10

 Pitch motor drive circuit of the prior art

12

 supply network

14

 Pitch motor-inverter

16

 Rectifier means

18

 Inverter means

20

 DC smoother / Notbetriebsversorgungseinrichtung

22

 Rectifier diode

24

 Inverter IGBT

26

 Freewheeling diode

28

 pitch engine

30

 motor phase

32

 Engine supply phase

34

 DC link

36

 Phase angle control device

38

40

 Pitch motor drive circuit

42

 Pitch motor drive circuit

44

 Pitch motor drive circuit

46

 Pitch motor drive circuit

48

 Pitch motor drive circuit

50

 Ladeumrichtervorrichtung

52

 Motorumrichtervorrichtung

54

 local area network

56

 High capacity emergency power supply

58

 Charging current sensor device

60

 Ladeumrichter controller

62

 Slip ring contact device

64

 Information transmission apparatus

66

 Powerline coupling device rotation side

68

 Powerline coupling device-stationary side

70

 filter means

72

 filter inductor

74

 filter capacity

76

 transformer device

78

 Bypass switch means

80

 Coupling switching device

82

 AFE inverter

84

 Active rectifier device

86

 B12 transformer and rectifier device

88

 YΔ transformer

90

 6p-rectifier device

92

 Motor decoupling switching device

94

 Feedback switching device

96

 Network disconnection device

98

 Pitch motor drive circuit

100

 Wind turbine

102

 mast

104

 gondola

106

 rotor hub

108

 rotor blade

110

 Pitch actuator

112

 pitch gear

114

 Pitch gearbox input shaft

116

 pitch angle

118

 Insulation monitoring device

Claims (13)

Pitch motor drive circuit ( 40 . 42 . 44 . 46 . 48 . 98 ) for a wind or hydroelectric power plant ( 100 ) comprising at least one, a pitch motor ( 28 ) associated motor converter device ( 52 ) comprising a rectifier device ( 16 ), an inverter device ( 18 ) and one in the DC link ( 34 ) intermediate rechargeable emergency power supply ( 56 ), characterized in that the at least one motor converter device ( 52 ) at least one with a supply network PG ( 12 ) connected load converter device ( 50 ), wherein the charging converter device ( 50 ), the motor converter device ( 52 ) with a local area network ( 54 ) to supply. Pitch motor drive circuit ( 40 . 42 . 44 . 46 . 48 . 98 ) according to one of the preceding claims, characterized in that a charging converter device ( 50 ) the local area network ( 54 ) for all motor inverter devices ( 52 ) of the wind or hydroelectric power plant ( 100 ). Pitch motor drive circuit ( 40 . 42 . 44 . 46 . 48 . 98 ) according to one of the preceding claims, characterized in that the charging converter device ( 50 ), the local area network ( 54 ) having a frequency greater than the network frequency of the supply network PG ( 12 ), in particular to operate at 400Hz or higher. Pitch motor drive circuit ( 40 . 42 . 44 . 46 . 48 . 98 ) according to one of the preceding claims, characterized in that a control device ( 60 ) of the at least one charging converter device ( 50 ), charging current control information of the emergency operating device ( 56 ), in particular charging current and / or state of charge of an emergency power supply device ( 56 ) Energy storage, in particular an integrated double-layer capacitor or supercap energy storage, and is further configured, this control information for controlling the amplitude height, amplitude shape and / or frequency of the local area network ( 54 ). Pitch motor drive circuit ( 40 . 42 . 44 . 46 . 48 . 98 ) according to one of the preceding claims, characterized in that the at least one charging converter device ( 50 ) in the stationary part of the wind or hydroelectric power plant ( 100 ), especially in a gondola ( 104 ) of a wind turbine ( 100 ) and the motor inverter devices ( 52 ) in the rotating part, in particular in a rotor hub ( 106 ), wherein preferably control information from a motor converter device ( 52 ) to the charging converter device ( 50 ) and vice versa via an information transmission device ( 64 ), in particular via a slip ring contact device ( 62 ) are transferable. Pitch motor drive circuit ( 40 . 42 . 44 . 46 . 48 . 98 ) according to one of the preceding claims, characterized in that between the charging converter device ( 50 ) and motor converter device ( 52 ) a filter device ( 70 ) is arranged. Pitch motor drive circuit ( 40 . 42 . 44 . 46 . 48 . 98 ) according to one of the preceding claims, characterized in that between the charging converter device ( 50 ) and motor converter device ( 52 ) and / or between supply network PG ( 12 ) and load converter device ( 50 ) a voltage adjustment device, in particular a transformer device ( 76 ) or a phase control device ( 36 ) is arranged. Pitch motor drive circuit ( 40 . 42 . 44 . 46 . 48 . 98 ) according to one of the preceding claims, characterized in that at least one of the motor converter devices ( 52 ) and / or the at least one charging converter device ( 50 ) an active rectifier device ( 84 ) or a phase control device ( 36 ). Pitch motor drive circuit ( 40 . 42 . 44 . 46 . 48 . 98 ) according to one of the preceding claims, characterized in that the at least one charging converter device ( 50 ) and / or at least one motor converter device ( 52 ) by a bridging switching device ( 78 ) is bridgeable. Pitch motor drive circuit ( 40 . 42 . 44 . 46 . 48 . 98 ) according to one of the preceding claims, characterized in that at least two charge converter devices ( 50 ), wherein a plurality of coupling switching devices ( 80 . 94 ) at least one charging converter device ( 50 ) with each motor converter device ( 52 ) is connectable. Pitch motor drive circuit ( 40 . 42 . 44 . 46 . 48 . 98 ) according to one of the preceding claims, characterized in that an insulation monitoring device ( 118 ) in the local area network ( 54 ), which are preferably located in or adjacent to the charging converter device ( 50 ) and the local area network ( 54 ) is monitored for insulation faults. Method for operating a pitch motor drive circuit ( 40 . 42 . 44 . 46 . 48 . 98 ) according to any one of the preceding claims, characterized in that depending on the charging current and / or the state of charge at least one in an emergency operating device ( 20 ) Energy storage included an amplitude level, voltage waveform and / or frequency of the local area network ( 54 ) of the charging converter device ( 50 ) is adjusted in particular for smoothing harmonics. A method according to claim 12, characterized in that in the case of a decreasing state of charge, a trapezoidal amplitude curve of the charging voltage is selected so that a predetermined maximum allowable charging current is not exceeded.

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