Abstract

The invention provides an improved stator (28) for rotating electrical machines with single-layer stator windings consisting of a plurality of pre-formed coils (22) of equal angular pitch. The stator (28) has a first cylindrical surface in which a plurality of circumferentially spaced winding slots (30) are formed and in which the axially- extending winding runs (24) of the pre-formed coils (22) are positioned. The two winding runs (24) of each coil (22) will each be positioned in a winding slot (30) and the two winding slots (30) that receive the coil (22) define a winding slot pair. The improvement arises from the fact that the winding slots (30) of each winding slot pair extend into the stator (28) in substantially parallel directions. This means that the axially-extending winding runs (24) of each pre-formed coil (22) may also be substantially parallel and need not be angled towards each other. This enables the stator (28) to be easily wound as each pre-formed coil (22) may be simply and easily slotted into a parallel winding slot pair.

IPC Classes  ?

• H02K 1/16 - Stator cores with slots for windings

Abstract

The present invention provides_a power converter that can be used to interface a generator (4) that provides variable voltage at variable frequency to a supply network operating at nominally fixed voltage and nominally fixed frequency and including features that allow the power converter to remain connected to the supply network and retain control during supply network fault and transient conditions. The power converter includes a generator bridge (10) electrically connected to the stator of the generator (4) and a network bridge (14). A dc link (12) is connected between the generator bridge (10) and the network bridge (14). A filter (16) having network terminals is connected between the network bridge (14) and the supply network. A first controller (18) is provided for controlling the operation of the semiconductor power switching devices of the generator bridge (14). Similarly, a second controller (46) is provided for controlling the operation of the semiconductor power switching devices of the network bridge (14). The first controller (18) uses a dc link voltage demand signal (VDC_GEN*) indicative of a desired dc link voltage to control the semiconductor power switching devices of the network bridge (10) to achieve the desired level of dc link voltage that corresponds to the dc link voltage demand signal (VDC_GEN*). The second controller (46) uses a power demand signal (P*) indicative of the level of power to be transferred from the dc link to the supply network through the network bridge (14), and a voltage demand signal (VTURB*) indicative of the voltage to be achieved at the network terminals of the filter (16) to control the semiconductor power switching devices of the network bridge (14) to achieve the desired levels of power and voltage that correspond to the power and voltage demand signals (P* and VTURB*).

IPC Classes  ?

• H02P 9/04 - Control effected upon non-electric prime mover and dependent upon electric output value of the generator
• H02J 3/38 - Arrangements for parallelly feeding a single network by two or more generators, converters or transformers
• F03D 7/02 - Controlling wind motors the wind motors having rotation axis substantially parallel to the air flow entering the rotor

Abstract

The electronic commutator circuits of the present invention provide forced commutation means that can be embedded within a known electronic commutator to overcome its low speed torque limitation. The forced commutation means consists of forced commutation enhancements to the basic switched stage using a pair of thyristors (1, 4). Capacitors (3, 6) may be pre-charged and synchronised to supplement coil voltages when discharged, thereby reducing commutation overlap duration and maximising the turn-off time available to allow the thyristors (1, 4) to attain forward blocking capability. Two means of providing such a capacitive discharge can be used. The first means initiates the capacitive discharge by the same thyristor that will carry the current following the commutation. The second means initiates the capacitive discharge by an auxiliary thyristor.

IPC Classes  ?

• H02P 6/14 - Electronic commutators

Abstract

An electric power converter combination converts AC power from a main AC supply network (1) to DC power to supply a DC load (2), the converter combination comprising a phase controlled thyristor supply bridge rectifier (4) and an auxiliary PWM converter (10) connected across a DC output filter (8) of the thyristor supply bridge (4), the auxiliary PWM converter (10) also being connected to a power supply comprising either the main AC supply network (1), an AC supply independent of the main AC supply network, or a low voltage DC supply.

IPC Classes  ?

• H02M 7/17 - Conversion of AC power input into DC power output without possibility of reversal by static converters using discharge tubes with control electrode or semiconductor devices with control electrode using devices of a thyratron or thyristor type requiring extinguishing means using semiconductor devices only arranged for operation in parallel
• H02M 7/23 - Conversion of AC power input into DC power output without possibility of reversal by static converters using discharge tubes with control electrode or semiconductor devices with control electrode using devices of a triode or transistor type requiring continuous application of a control signal using semiconductor devices only arranged for operation in parallel