MXPA06004530A - Electrical machine and method of controlling the same - Google Patents

Abstract

A method of controlling an electrical machine having a stator and a rotor. The stator includes a core and a plurality of windings disposed on the core in a three-phase arrangement. The three-phase arrangement includes a first, second, and third phases having a first, second, and third terminals, respectively. The rotor is disposed adjacent to the stator to interact with the stator. The method includes applying a pulsed voltage differential to the first and second terminals resulting in movement of the rotor;monitoring the back electromotive force (BEMF) of the third phase to sense rotor movement;after the applying and monitoring steps, monitoring the BEMF of each of the first, second, and third phases to determine whether the rotor is rotating in a desired direction, and electrically commutating the motor when the rotor is rotating in the desired direction and zero or more other conditions exist.

Description

ELECTRICAL MACHINE AND METHOD TO CONTROL THE SAME RELATED REQUEST This application claims the benefit of the Patent Application of United States number 60 / 514,366, filed on October 24, 2004, entitled "Electrical Machine", the entire contents of which is incorporated herein by reference.

FIELD OF THE INVENTION The invention relates to an electrical machine and specifically to a brushless electric machine.

BACKGROUND AND BRIEF DESCRIPTION OF THE INVENTION Direct current brushless motors (BLDCs) are becoming more common in industries that typically do not use BLDC motors. For example, the need for greater efficiency in the heating and air conditioning market has led to the use of BLDC motors to energize the blower. The BLDC motors, which may also be called electrically commutated motors (ECM), include a rotor having a plurality of magnetic poles (e.g., a plurality of poles produced with permanent magnets) of alternating polarity disposed on a surface of a center of rotor, and a stator that receives electrical power and produces magnetic fields in response to this. The magnetic field of the stator interacts with the magnetic field of the rotor to cause rotor movement. BLDC motors require a method to determine the position of the rotor to switch the motor. One method of switching the motor is called "sensorless" motor switching. Switching of the sensorless motor is typically done by sensing the reverse electromotive force (BEFM) produced by the motor. Typically, the BEMF signal produced in the stator windings is not large enough for sensorless motor switching until the rotor speed reaches about ten percent of the normal motor speed. As a result, a method to start the engine without using the BEFM signal may be necessary. For a three-phase motor, one method of starting the motor is to align the rotor by supplying current to one phase of the motor and wait until the rotor has stopped oscillating, then pass through the other phases of the motor (with each of the phases subsequently becoming shorter, thus raising the speed without any position feedback) until the rotor reaches 10% of the normal speed. This method has at least two disadvantages. First, the time required during the alignment phase can be long when the inertia of the connected load is large and the friction is low (for example, if the load is a large blower). Second, information about the load (for example, inertia and torsional torque) is typically necessary to move the motor step by step. The purpose of aligning the rotor as described above is to start the engine from a known position of the rotor. One way to avoid this alignment process is knowing the position of the rotor in some other way. The second disadvantage described above can be overcome by not going step by step blindly (without information on the position of the rotor) but knowing the position of the rotor almost at zero speed. In one embodiment, the invention provides a method for controlling an electrical machine having a stator and a rotor. The stator includes a center and a plurality of windings arranged in the center in a three-phase arrangement. The three-phase array includes a first phase, a second phase, and a third phase having a first Terminal, a second Terminal, and a third Terminal, respectively. The rotor is arranged adjacent to the stator to interact with the stator. The method includes the steps of applying a pulsed voltage differential to the first and second terminals resulting in the movement of the rotor; monitor the reverse electromotive force (BEFM) of the third phase to detect the movement of the rotor; after the application and monitoring steps, it monitors the BEFM of each of the first, second and third phases to determine the direction of rotation of the rotor; determine if the rotor is rotating in a desired direction, and electrically switch the motor when the rotor is rotating in the desired direction and zero or more additional conditions exist.

BRIEF DESCRIPTION OF THE DRAWINGS Figure 1 is a partial exploded view of the stator and rotor of an electric machine with permanent magnets. Figure 2 is an isometric view showing the geometry used to define an arc of magnetization obliquity (ß) in the rotor. Figure 3 is a longitudinal view of a contrition of the rotor of Figure 1. Figure 4 is a cross-sectional view of a stator and rotor center capable of being used in the electrical machine of Figure 1. Figure 5 is a block diagram of a power electric circuit capable of energizing the electrical machine of Figure 1. Figure 6 is an example of a stator winding pattern in a double layer arrangement with compact coils for an 18-slot three-phase machine, 12 poles Figure 7 is an example of a stator winding pattern in a one-layer arrangement with compact coils for a 12-slot, 18-slot, three-phase machine. Figure 8 has schematic diagrams representing three pulses applied to a three-phase motor. Figure 9 represents a comparison of the BEFMs for a three-phase machine.

DETAILED DESCRIPTION OF THE INVENTION Before any form of the invention is explained in detail, it should be understood that the invention is not limited in its application to the details of construction and arrangement of components set forth in the following description or illustrated in the following drawings. The invention is capable of other modalities and of being practiced or carried out in various ways. Also, it should be understood that the phraseology and terminology used herein are for descriptive purposes and should not be construed as limiting. The use of "including", "comprising", or "having" and variations of the same here attempt to encompass the objects listed there and their equivalents as well as additional objects. The terms "connected", "coupled", "supported", and "assembled" and variations thereof are widely used herein and, unless otherwise specified, encompass both connections, couplings, supports, and direct and indirect assemblies. . Additionally, the terms "connected" and "coupled" and variations thereof are not restricted to physical and mechanical connections and couplings. Lots of a brushless direct current machine (BLDC) embodying the invention is shown in Figures 1-6. However, the invention is not limited to the machine described in Figures 1-6; other BLDC machines may incorporate the invention. Figure 1 is a partial exploded view of the stator and rotor of a construction of an electrical machine (e.g., engine, generator, etc.). For Figure 1, the electric machine is a motor 10 having a rotor 15 and a stator 20. The rotor 15 is coupled to the shaft 17. In general, the stator 20 receives electrical power, and produces a magnetic field in response to the same The magnetic field of the stator 20 interacts with the magnetic field of the rotor 15 to produce mechanical power on the shaft 17. The invention hereinafter refers to the electric motor 10. The rotor 15 includes a plurality of magnetic poles 25 of alternating polarity exhibited in a surface of the rotor center 30. The rotor center 30 includes laminations (e.g., laminations of magnetic steel), and / or solid material (e.g., a center of solid magnetic steel), and / or compressed powder material (e.g., powder). Magnetic steel tablet). A construction of the rotor 15 includes a sheet of permanent magnet material (eg magnetic hard) disposed at the rotor center 30. Another construction of the rotor 15 may include a plurality of strips of permanent magnet material adhered (eg, with adhesives) around the center 30. The permanent magnet material can be magnetized by a magnetizer to provide a plurality of alternating magnetic poles. Additionally, the number of magnetic strips can be different than the number of magnetic poles of the rotor. Yet another construction of the rotor 15 contains blocks of permanent magnet material placed within the rotor center 30. The description of the invention is not limited to a mechanical construction, geometry, or position of the rotor 15 in particular. For example, Figure 1 shows the rotor 15 located inside and separated by a radial air gap of the stator 20. In another construction, the rotor 15 can be positioned radially on the outside of the stator 20 (that is, the machine is a external or external rotor). A method for reducing the torsional gear and ripple torque, which may be necessary in some BLDC motors, is to bias the magnetization of the magnetic poles 25 with respect to the stator 20. Alternatively, stator teeth in the stator 20 may be biased with respect to to magnetization of the rotor. As shown in Figures 1 and 2, the "magnetization" of the rotor 15 refers to the linear pattern 31 along the length of the rotor 15 delineating alternating magnetic poles 25 in the rotor center 30. Figure 2 illustrates the concepts geometries involved in defining the magnetization bias of the rotor. The magnetization bias arc can be defined as the arc (ß), measured in radians between the longitudinal lines 32 and 33 (see figure 2) on the surface of the rotor in front of the air gap, which separates the stator and the rotor. Figure 3 is a schematic diagram of a construction of the rotor 15 divided into a plurality of axial sections 55 (for example 70, 71 and 72) along the rotational axis 50 of the rotor 15. The number of axial sections 55 may vary and It is not limiting in the invention. An axial section 55 refers to a portion of the rotor 15 differentiated by imaginary lines 60.

The imaginary lines 60 refer to locations in the rotor 15 where the bias direction of the magnetization pattern 31 changes. A construction of the rotor 15 includes alternating magnetic poles with an arc of magnetization bias (β) substantially equal along each axial section 55, resulting in a fishbone magnetization pattern. The length of each axial section 55 may vary. Figure 3 shows a construction of the rotor 15 including three axial sections 70, 71, and 72. The stator 20 interacts with one or more of the three axial sections 70, 71, and 72. The first axial section 70 includes aligned magnetic poles. with a first direction of bias, the second axial section 71 includes magnetic poles aligned with a second direction of bias, and the third axial section 72 includes magnetic poles aligned with the first direction of bias. The total number of axial sections and the total number of rates for a given engine profile are not limiting in the invention. Various designs of stators 20 can be used to interact with each construction of the rotor 15 described above and shown in Figures 1-3. The following is a description of a construction of the invention that includes the radially disposed rotor 15 of the stator 20. With reference to FIGS. 1 and 4, the stator 20 includes a stator center 105 having a plurality of stator teeth 110 and stator windings 112. In one construction, the stator center 105 includes a stack of laminations or sheets of magnetic steel. In other constructions, the stator center 105 is formed of a solid block of magnetic material, such as compressed magnetic steel powder. Stator windings 112 include electrical conductors placed in the slots 120 and around the plurality of teeth 110. Other constructions and types of stator center 105 and stator windings 112 known to those skilled in the art can be used and are not limiting. the invention. The electric current flowing through the stator windings 112 produces a magnetic field that interacts with the magnetization of the rotor 15 to provide torsional torque to the rotor 15 and to the shaft 17. The electric current can be an alternating current (AC) of phase (m), where (m) is an integer greater than or equal to two. The electric current can have several types of waveform (for example, square wave, quasi-sine wave, etc.). The stator windings 112 receive an electric current from a power electric circuit. A construction of an electrical power circuit 125 configured to energize the motor 10 is shown in FIG. 5. In general, the power circuit 125 receives power from a power source 130 and energizes the motor 10 in response to an input (for example an input device 130 such as a user input). With reference to Figure 5, the power circuit 125 receives AC power from a power source 130. The AC power is provided to a filter 140 and a rectifier 140 that filter and rectify the AC power, resulting in a common conductor voltage VDC The common conductor voltage VDC is provided to an inverter 150 and a voltage divider 155. The voltage divider reduces the common conductor voltage 155 to a value capable of being acquired by the controller 160 (at terminal 162). The controller 160 includes a processor 165 and a memory 170. Generally speaking, the processor reads, interprets, and executes instructions stored in the memory 170 to control the power circuit 125. Of course, the controller 160, which may be in the form of a microcontroller, can include other components such as a power source, an analog-to-digital converter, filters, etc. The controller 160 outputs power signals at terminals 175 and 180 to control the inverter 150. The inverter includes electronic power switches (e.g., MOSFETs, IGBTs) to vary the flow of current to the motor. For example, and in a construction, the inverter can be in the form of a bridge circuit. A detection resistor 185 is used to generate a voltage that is related to the common conductor current of the inverter 150. The voltage of the detection resistor 185 is provided to the controller 160 at terminal 187. Other methods for detecting current can be used to detect the common conductor current. It is also envisaged that the controller 160 may receive values associated with the phase currents provided by the inverter 150. The power circuit 125 also includes a voltage divider of BEMF 190 and variable gain amplifiers 195. The voltage divider of BEMF 190 and variable gain amplifiers 195A-C provide voltage values to controller 160 at terminals 200A-C. The voltage values provided to the controller 160 by the variable gain amplifiers 195A-C have a relation to the BEFM of each phase voltage.

In operation, the controller 160 controls the motor by providing power signals to the inverter based on inputs received in the controller 160. Examples of inputs include an input received from an input device 135, the common conductor voltage, the common conductor current, and the BEFM voltages. Further explanation related to the operation of the machine is provided below. Figure 4 shows a cross section profile of a cross section of the motor perpendicular to the axis 50 used in a motor construction (the stator windings 112 are not shown in Figure 6). The stator center 105 includes a plurality of stator teeth 110, grooves 120, and a rear iron portion 115. Each of the plurality of stator slots 120 receives one or more stator coils, the assembly of which constitutes the stator coils. stator windings 112. Stator windings receive a multi-phase electric current, where the number of phases (m) is an integer greater than or equal to two. The number (t) of stator teeth 110 is equal to the number of slots 120, where (t) is an integer. A slot 120 is defined by the space between adjacent stator teeth 110. The rotor 15 is produced, in one construction, by fixing three arc-shaped magnets 26 in a rotor center 30. Other designs and constructions of rotors are also possible. A magnetizer is used to produce, in the rotor 15, a number (p) of alternating magnetic poles interacting with the stator 20. The stator center 105 having the construction described above can be used to design and manufacture motors with several electric phases ( m), with windings 112 composed of compact coils (see the winding patterns in figure 6 and figure 7) and rotors having poles (p). A construction of the stator windings 112 includes a double layer arrangement of compact coils (FIG. 6), which are placed around each tooth (that is, the coils have a pitch of a groove). In this double layer arrangement, each slot is shared by two sides of coils, each of the coil sides belonging to a different coil and phase. The coil sides that share a slot can be placed side by side or one on top of the other. The double layer arrangement for an example of a winding of 18 slots, 12 poles, 3 phases is shown in figure 6. Another construction of the windings 112 includes an arrangement of a layer of compact coils (figure 7), which are placed around every second tooth (that is, the coils have a pitch of a groove and are only placed around half the number of teeth). In this single layer arrangement, each slot contains only one side of the coil. This one-layer winding pattern for an example of an 18-slot, 12-pole, 3-phase winding is shown in Figure 7. A typical manufacturing technique for providing a double-layer stator winding with compact coils includes the use of a needle or gun wire feeder. A typical manufacturing technique for providing single layer stator windings with compact coils includes the use of an insert feeder. Other types and techniques known to those skilled in the art for providing the stator windings 112 of the stator 20 can be used. As explained above, the power circuit 125 can estimate the position of the rotor 15 through what is known as sensorless control. Switching of the sensorless motor is often done by detecting the reverse electromotive force (BEMF) produced by the motor 10. Typically, the BEMF signal produced in the stator windings 112 is not large enough for the switching of the motor until the speed of the rotor 15 reaches about 10% of the normal speed of the motor 10. Described below, it is a starting procedure for starting a BLDC motor 10 using sensorless control. The start-up procedure is described below in three sections. The first section is a section for detecting the position of the rotor. The second section is a section of initial pulsation. The last section is a low speed BEMF detection section. The boot procedure is stored as software instructions in memory 170. Processor 165 reads memory instructions 170, interprets the instructions, and executes the interpreted instruction resulting in the operation of the motor 10 as described below. Of course, other circuit components (eg, an ASIC) may be used in linking of processor 165 and memory 170 to control motor 10.

A. Detection of the Initial Position of the Rotor The detection of the initial position of the rotor 15 is based on a more simplified version of U.S. Patent No. 5,001, 405 (the '405 Patent), which is fully incorporated herein by reference. The '405 patent discloses a method for exciting a phase of a three-phase motor with a polarity, and then, exciting the same phase with the opposite polarity. Through a comparison of the peak current, the rotor position is known to be within 60 degrees. The starting algorithm employed within a construction of the invention does not excite the winding with the opposite current. This reduces the initial position resolution to 120 degrees (for a three-phase motor). Using this more simplified method with the other sections provides enough information to start the engine 10 in the right direction. In one construction, the controller 160 uses the following sequence of pulses: Pulse [0] = On, Bdc, Laid (the current enters phase B and returns in phase A); Pulse [1] = Adc, Bapagado, Cencendido (the current enters phase A and returns in phase C); Pulse [2] = Agap, Bended, Cdc (current enters phase C and returns in phase B); where de represents a pulsed common conductor voltage, on represents the phase on ground, and off represents non-current on the winding (see figure 8). The current is measured at the end of each pulse. The sequence with the highest current determines the position of the rotor and to which phase to apply the first pulse movement. In another construction, the controller 160 uses the following sequence of pulses: Pulse [0] = Abandoned, Bdc, Cdc (current enters phase B and returns in phases A and C); Pulse [1] = Adc, Bdc, Cencendido (the current enters phase A and returns in phases C and B); Pulse [2] = Adc, Bended, Cdc (current enters phase C and returns in phases B and A); where de represents a common conductor voltage pulsed and on represents the phase to ground. The current is measured at the end of each pulse. The sequence with the highest current determines the position of the rotor and to which phase to apply the first pulse movement. The winding sequence with the highest current is the winding that has the magnet most aligned with the field created by the winding. It is assumed that the direction of the current is also the direction of the north pole created by the winding current. For the example shown in figure 8, phase B has the most aligned magnet (PulseParalelo [2]). Therefore, in a six-step switching sequence, the next sequence to turn on is the Switchover [0] or an intermediate sequence of Ade, Bended, Layered. Preferably, the durations of the initial rotor pulses are sufficiently fast and the current level small enough not to cause the movement of the rotor 15.

B. Initial Pulse An initial pulse, long enough to cause movement of the rotor 15, is applied to the appropriate phase of the information collected from the previous section. The duty cycle or voltage applied to winding 112 is established during the initial pulse such that the voltage for the phase that is open can be amplified to a level at which movement is detected by monitoring a change in voltage. If the initial pulse is too large then the motor accelerates too fast causing a torsional torque change that results in undesirable audible noise at start-up. If the initial pulsed voltage is too small then there may not be enough torsional torque to cause movement in the rotor. The initial movement of the rotor 15 depends on where the rotor is located within the 120 degree window. Sampling the BEMF at the start of the pulse establishes a baseline voltage before the movement has occurred. The BEMF is then monitored for a change in voltage, which is related to the movement of the rotor. During the initial pulse sequence, the rotor 15 can actually move backwards before it moves forward. If this occurs, the controller 160 applies a braking pulse to stop or encourage movement of the rotor, and the rotor 160 returns to the previous section.

C. Cruise; detect BEMF crosses (low speed BEMF detection method). Once movement is detected and all phases are turned off, the BEMF is monitored for phase crossings. The negative half of the BEMF is fixed by diodes in the inverse 150. A switching point occurs when the BEMF phases intersect (see figure 9). More specifically, the software monitors three parameters: 1) Afase > B phase 2) B phase > Cfase 3) Cfase > Afase These parameters are used to decode the rotor switching position as follows: At the first change in any of the three conditions, the software starts a timer, and then, subsequently searches for the next "proper" transition. This is to ensure that the motor 10 is rotating in the correct direction. At the second change in the condition of BEMF, the software stops the timer and measures the period. The controller 160 then switches the motor with the appropriate phase switching sequence (assuming the rotor is rotating in the correct direction). The software keeps the phase on as specified in the previous period, while searching for a conventional BEMF zero crossing event. The motor 10 can then switch as is conventionally known in the art. For example, the controller 160 may use a six-step control technique to move the motor 10. An example of a six-step phase sequence for switching the motor is Switching [0] = Adc, Bended, Lagging (current enters phase A and return in phase B); Switching [1] = Adc, Bapagado, Cencendido (the current enters phase A and returns in phase C); Switching [2] = Off, Bdc, Canceled (the current enters phase B and returns in phase C); Switching [3] = On, Bdc, Lagging (the current enters phase B and returns to phase A); Switching [4] = On, Bapagado, Cdc (current enters phase C and returns in phase A); Switching [5] = Off, Bended, Cdc (current enters phase c and returns in phase B); where de represents a common conductor voltage pulsed and on represents the ground phase.

Claims (37)

NOVELTY OF THE INVENTION CLAIMS

1. A method for controlling an electrical machine comprising a stator comprising a center and a plurality of windings arranged in the center in a three-phase arrangement, the three-phase arrangement comprises a first phase, a second phase and a third phase having a first terminal, a second terminal, and a third terminal, respectively, and a rotor disposed adjacent the stator to interact with the stator, the method comprising: applying a pulsed voltage differential from the first terminal to the second terminal resulting in the movement of the rotor; After the application step, monitor the BEMF in each of the first, second and third phases to determine the direction of rotation of the rotor, determine if the rotor is rotating in a desired direction, and electrically switch the motor when the rotor is rotating in the desired direction and zero or more additional conditions exist.

The method according to claim 1, further characterized by additionally comprising, between the application and monitoring steps, monitoring the reverse electromotive force (BEMF) of the third phase to detect the movement of the rotor.

3. The method according to claim 1, further characterized in that the pulsed voltage differential is a fourth pulsed voltage differential; and wherein the method further comprises applying a first pulsed voltage differential from the second terminal to the first terminal, the first pulsed voltage differential results in no substantial movement of the rotor, acquiring a first value having a relation to the resulting current of the first pulsed voltage differential, apply a second differential of pulsed voltage from the first terminal to the third terminal, the second differential of pulsed voltage that results in no substantial movement of the rotor, acquire a second value that is related to the current that results of the second pulsed voltage differential, apply a third differential of pulsed voltage from the third terminal to the second terminal, the third differential of pulsed voltage that results in no substantial movement of the rotor, and acquire a third value that is related to the current that results from the third voltage differential pulsed.

4. The method according to claim 3, further characterized in that the method further comprises determining which of the first, second, and third values has the greatest magnitude, and where applying the fourth pulse voltage differential and monitoring the BEMF occurs when the third value has the greatest magnitude and zero or more additional conditions exist.

The method according to claim 4, further characterized by additionally comprising: when the second value has the greatest magnitude and zero or more additional conditions exist, applying the fourth voltage differential pulsed from the second terminal to the third terminal, the fourth differential of pulsed voltage that results in the movement of the rotor; and monitor the BEMF of the first phase to detect the movement of the rotor.

The method according to claim 4, further characterized by additionally comprising: when the first value has the greatest magnitude and there are zero or more additional conditions, apply the fourth pulse voltage differential of the third terminal to the first terminal, the fourth differential of pulsed voltage that results in the movement of the rotor; and monitor the BEMF of the second phase to detect the movement of the rotor.

The method according to claim 3, further characterized in that the magnitudes of the first, second, and third pulsed voltage differentials are approximately equal.

The method according to claim 3, further characterized in that the first value has a relation to a common conductor current resulting from the first pulsed voltage differential.

The method according to claim 3, wherein further characterized in that the first value has a relation to a phase current resulting from the first pulsed voltage differential.

10. The method according to claim 1, further characterized in that the application and monitoring steps occur at least partially simultaneously.

11. The method according to claim 1, further characterized by additionally comprising: after the application and monitoring steps, monitor the BEMF of each of the first, second, and third phases to determine the rotation speed of the rotor.

The method according to claim 1, further characterized in that monitoring the BEMF of each of the first, second, and third phases comprises monitoring for changes in at least one of the following conditions if the BEMF of the first phase is greater than the MBEMF of the second phase, and if the BEMF of the second phase is greater than the BEMF of the third phase, and if the BEMF of the third phase is greater than the BEMF of the first phase; and wherein the method further comprises determining the rotation direction of the rotor based on the monitoring for step changes.

The method according to claim 12, further characterized by comprising: after the application and monitoring steps, determine the rotor speed based on the monitoring for step changes.

The method according to claim 13, further characterized in that the rotor switching is based on the speed of the rotor.

The method according to claim 1, further characterized in that the pulsed voltage differential is a fourth pulsed voltage differential; and wherein the method further comprises applying a first pulsed voltage differential to the terminals resulting in a current from the second terminal to the first and third terminals, the first pulsed voltage differential resulting in no substantial movement of the rotor, acquiring a first value having a relation to a current resulting from the first pulsed voltage differential, applying a second differential of pulsed voltage to the terminals that results in a current from the first terminal to the second and third terminals, the second differential of pulsed voltage that result in no substantial movement of the rotor, acquire a second value that is related to a current resulting from the second differential of pulsed voltage, apply a third differential of pulsed voltage to the terminals resulting in a current from the third terminal to the first and second terminals, the third pulse voltage differential that results in no movement In the case of the rotor, to acquire a third value that is related to a current that results from the third differential of pulsed voltage.

16. The method according to claim 15, further characterized in that the method further comprises determining which of the first, second and third values has the greatest magnitude; and where applying the fourth pulse voltage differential and monitoring the BEMF occur when the third value has the greatest magnitude and there are zero or more additional conditions.

The method according to claim 16, further characterized by additionally comprising: when the second value has the greatest magnitude and zero or more conditions exist, apply the fourth differential of pulsed voltage from the second terminal to the third terminal, the fourth Pulsed voltage differential resulting in rotor movement; and monitor the BEMF of the first phase to detect the movement of the rotor.

18. The method according to claim 16, further characterized by additionally comprising: when the first value has the greatest magnitude and zero or more conditions exist, apply the fourth differential of pulsed voltage from the third terminal to the first terminal, the fourth Pulsed voltage differential resulting in rotor movement; and monitor the BEMF of the second phase to detect the movement of the rotor.

19. The method according to claim 15, further characterized in that the first value has a relation to a common conductor current of the first pulsed voltage differential.

20. The method according to claim 15, further characterized in that the first value has a relation to a phase current resulting from the first pulsed differential.

21. A method for controlling an electrical machine comprising a stator comprising a center and a plurality of windings arranged in the center in a three-phase arrangement, the three-phase arrangement comprising a first phase, a second phase, and a third phase having a first terminal, a second terminal, and a third terminal, respectively, and a rotor arranged adjacent the stator to interact with the stator, the method comprising: applying a first differential of pulsed voltage from the second terminal to the first terminal, the first pulsed voltage differential that results in no substantial movement of the rotor, acquiring a first value that is related to a current resulting from the first pulsed voltage differential, applying a second pulsed voltage differential from the first terminal to the third terminal, the Second differential of pulsed voltage that results in no substantial movement of the rotor, acquire a second value that has a relation to a current that results from the second differential of pulsed voltage, apply a third differential of pulsed voltage from the third terminal to the second terminal, the third differential of pulsed voltage that results in no substantial movement of the rotor, acquire a third value that has relation to a current that results from the third differential of pulsed voltage, determine which of the first, second, and third values has the greatest magnitude; apply a fourth voltage differential pulsed to the terminals based on the determination step, the fourth pulse voltage differential that results in rotor movement; monitor the reverse electromotive force (BEMF) of the phase that has no pulse to detect the movement of the rotor; after applying the fourth pulse voltage differential and monitoring the BEMF, monitor the BEMF of each of the first, second, and third phases; monitor for changes in at least one of the following conditions if the BEMF of the first phase is greater than the BEMF of the second phase, if the BEMF of the second phase is greater than the BEMF of the third phase, and if the BEMF of the third phase is greater than the BEMF of the first phase; determine the direction of rotation of the rotor based on the monitoring by step changes; determine if the rotor is rotating in a desired direction; and electrically switching the motor when the rotor is rotating in a desired direction and there are zero or more additional conditions.

22. The method according to claim 21, further characterized by additionally comprising: after applying the fourth pulsed voltage differential and monitoring the BEMF, determining the rotor speed based on step change monitoring.

23. The method according to claim 21, further characterized in that the magnitudes of the first, second, and third pulsed voltage differentials are approximately equal.

24. The method according to claim 21, further characterized in that the first value has a relation to a common conductor current resulting from the first pulsed voltage differential.

25. The method according to claim 21, further characterized in that the first value has a relation to a phase current resulting from the first pulsed voltage differential.

26. The method according to claim 21, further characterized in that applying a fourth pulsed voltage and monitoring the BEMF to detect the movement of the rotor occur at least partially simultaneously.

27. A method for controlling an electrical machine comprising a stator comprising a center and a plurality of windings arranged in the center in a three-phase arrangement, the three-phase arrangement comprising a first phase, a second phase, and a third phase having a first terminal, a second terminal, and a third terminal, respectively, and a rotor disposed adjacent the stator to interact with the stator, the method comprising: applying a first differential of pulsed voltage to the terminals resulting in a current of the second terminal to the first and third terminals, the first differential of pulsed voltage that results in no substantial movement of the rotor, acquire a first value that is related to a current that results from the first differential of voltage pulsed, apply a second differential of voltage pulsed to the terminals resulting in a current from the first terminal to the second and third terminals, the second or pulsed voltage differential that results in no substantial movement of the rotor, acquiring a second value that is related to a current resulting from the second voltage differential pulsed, applying a third voltage differential pulsed to the terminals resulting in a current of the third terminal to the first and second terminals, the third pulsed voltage differential resulting in no substantial movement of the rotor, acquiring a third value that is related to a current resulting from the third voltage differential pulsed; Determine which of the first, second, and third values has the greatest magnitude; apply a fourth voltage differential pulsed to the terminals based on the determination step, the fourth pulse voltage differential that results in rotor movement; monitor the reverse electromotive force (BEMF) of the phase that has no pulse to detect the movement of the rotor; after applying the fourth pulse voltage differential and monitoring the BEMF, monitor the BEMF of each of the first, second, and third phases; monitor for changes in at least one of the following conditions if the BEMF of the first phase is greater than the BEMF of the second phase, if the BEMF of the second phase is greater than the BEMF of the third phase, and if the BEMF of the third phase in greater than the BEMF of the first phase; determine the direction of rotation of the rotor based on the monitoring by step changes; determine if the rotor is rotating in a desired direction; and electrically switching the motor when the rotor is rotating in the desired direction and zero or more additional conditions exist.

28. The method according to claim 27, further characterized by additionally comprising: after applying the fourth pulsed voltage differential and monitoring the BEMF, determine the rotor speed based on step change monitoring.

29. The method according to claim 27, further characterized in that the magnitudes of the first, second, and third pulsed voltage differentials are approximately equal.

30. The method according to claim 27, further characterized in that the first value has a relationship with a common conductor current resulting from the first pulsed voltage differential.

31. The method according to claim 27, further characterized in that the first value has a relation to a phase current resulting from the first differential pulse.

32. The method according to claim 27, further characterized in that applying a fourth pulsed voltage differential and monitoring the BEMF to detect rotor movement occurs at least partially simultaneously.

33. A method for controlling an electrical machine that includes a stator having a center and a plurality of windings arranged in the center in a multi-phase arrangement, and a rotor disposed adjacent the stator to interact with the stator, the method comprising : applying a first pulsed voltage to a first terminal of a first phase of the multi-phase array; monitor the inverse electromotive force (BEMF) of at least one phase of the multi-phase array; determine a peak value of BEMF; obtain a first monitored value of BEMF; compare the peak value of BEMF against the first monitored value of BEMF; and determine if the rotor is rotating based on the comparison.

34. The method according to claim 33, further characterized in that it further comprises determining a period indicative of rotational movement of the rotor in response to the first monitored value of BEMF that is less than the peak value of BEMF; and determining a rotational direction of the rotor.

35. The method according to claim 34, further characterized in that it further comprises determining the rotational speed of the rotor in response to the rotational direction of the rotor that is in a desired rotational direction; and electrically switching the motor in response to the rotational speed of the rotor that is less than a predetermined parameter.

36. The method according to claim 33, further characterized in that it further comprises preventing the movement of the rotor in response to the peak value of BEMF that is substantially similar to the first monitored value of BEMF.

37. The method according to claim 34, further characterized in that it further comprises preventing the movement of the rotor in response to determining that the rotational direction of the rotor is different from a rotational direction of the desired rotor.