WO2014089314A1

WO2014089314A1 - System, method, and circuitry to rectify an alternating current signal with mosfet half-bridge circuitry

Info

Publication number: WO2014089314A1
Application number: PCT/US2013/073355
Authority: WO
Inventors: German Holguin PALLARES
Original assignee: Remy Technologies, Llc
Priority date: 2012-12-05
Filing date: 2013-12-05
Publication date: 2014-06-12

Abstract

A system for rectifying an alternating current signal including MOSFET half-bridge circuitry, and magnitude detector circuitry configured to determine whether the peak magnitude of a phase signal is at least equal to a turn-on threshold level and enable the MOSFET half-bridge circuitry to rectify the phase signal in response to the peak magnitude of the phase signal at least equaling the turn-on threshold level. Also, a method for rectifying an alternating current signal including: receiving an alternating current signal from a stator; determining whether the magnitude of the alternating current signal is at least substantially equal to a turn-on threshold level; and, in response to a determination that the magnitude of the alternating current signal is at least equal to the turn-on threshold level, rectifying the alternating current signal to generate a supply voltage.

Description

SYSTEM, METHOD, AND CIRCUITRY TO RECTIFY AN

ALTERNATING CURRENT SIGNAL WITH MOSFET HALF-BRIDGE

CIRCUITRY

CROSS-REFERENCE TO RELATED APPLICATIONS

[0001] This application is related to PCT International Patent Application No.

PCT/US 13/72829 entitled ELECTRIC MACHINE AND ACCESSORY filed on December 3, 2013 (Attorney Docket No. 22888-0150), which claims priority to U.S. Provisional Patent Application Serial No. 61/733,552 entitled ELECTRIC MACHINE AND ACCESSORY filed on December 5, 2012 (Attorney Docket No. 22888-0080); and PCT International Patent Application No. PCT/US 13/73078 entitled ELECTRIC MACHINE HAVING ELECTRICAL BUSS AND MANUFACTURING METHOD THEREFOR filed on December 4, 2013 (Attorney Docket No. 22888-0149), which claims priority to U.S. Provisional Patent Application Serial No. 61/733,263 entitled SYSTEMS, DEVICES, AND METHODS FOR PROVIDING A POWER SUPPLY BUSS IN AN ELECTRICAL MACHINE filed on December 4, 2012 (Attorney Docket No. 22888-0079). This application claims priority to U.S. Provisional Patent Application Serial No. 61/733,679 entitled SYSTEM, METHOD, AND CIRCUITRY TO RECTIFY AN

ALTERNATING CURRENT SIGNAL WITH MOSFET HALF-BRIDGE CIRCUITRY filed on December 5, 2012 (Attorney Docket No. 22888-0082). The entire disclosures of all the above- listed patent applications are incorporated herein by reference.

BACKGROUND

[0002] The present disclosure relates to electric machines, and more particularly to improved thermal performance of electric machines.

[0003] An electric machine typically includes a stator affixed to a frame, a rotor that rotates relative to the stator, and a stator housing configured to at least partially enclose the machine. The frame relatively positions the stator and the rotor such that magnetic flux is channeled between them, and usually includes attachment points by which the machine may be secured for operation. Typically, the stator includes a generally cylindrical stator core containing windings of electric magnet wire; the windings normally have end turns located axially outside of the cylindrical stator core. Each stator winding corresponds to a phase of an alternating current signal. For example, an electric machine having three independent stator windings may be a three-phase electric machine in which the phase of each alternating current signal is separated from the other phases by 120 degrees. Similarly, electric machines having six independent stator windings may be a six -phase electrical machine.

[0004] Generally, electric machines receive or generate mechanical torque via their rotors. Electric machines that receive mechanical torque typically operate as electric generators which produce electric current in the stator windings induced by the electromagnetic interaction of the relatively rotating rotor and stator, whereas machines that generate mechanical torque typically operate as electric motors in which rotation of the rotor is electromagnetically induced by directing electric current through the stator windings. Some electric machines can selectively operate as either a generator or a motor.

[0005] The alternating current of each of the electrical windings may be rectified to produce a direct current. The direct current may power circuitry or charge an energy storage device. An alternator, for example, may provide current to a battery. In some embodiments, the electric machine includes a supply voltage regulator configured to regulate supply voltage or current.

[0006] Converting kinetic energy to electrical energy or electrical energy to kinetic energy may generate substantial heat due to resistive losses and switching losses. Electric machines typically include a cooling system having a fan that rotates in unison with the rotor to circulate cooling air through interior regions of the machine to remove heat from the stator and electronic componentry. Improvements in the design of electric machines for improving thermal characteristics and reducing interior heat buildup can further improve the thermal management of an electric machine and are desirable.

SUMMARY

[0007] Embodiments disclosed in the detailed description relate to electric machines and systems, devices, and methods for rectifying an alternating current signal with MOSFET half- bridge circuitry. An electric machine according to the present disclosure may include magnitude detector circuitry to control startup of the electric machine and thereby limit standby current drawn from an energy storage device. The magnitude detector circuitry may control the supply voltages that are used to control the MOSFET half-bridge circuitry. The magnitude detector circuitry determines whether the magnitude of a phase signal provided from a stator of the electric machine is at least equal to a turn-on threshold level. In response to the magnitude of the phase signal at least equaling the turn-on threshold level, the magnitude detector circuitry enables the MOSFET half-bridge circuitry to rectify the phase signal to produce a supply voltage. In response to the magnitude of the phase signal falling below the turn-on threshold level, supply voltage production is disabled.

[0008] Some embodiments of a multiphase electric machine according to the present disclosure include an electronic assembly having a power board and a control board configured to rectify the alternating current signal received from the stator of an electric machine. The power board and the control board may be located in a self-contained electronic module having at least a first phase terminal and a supply voltage terminal. The first phase terminal is in communication with a stator lead wire corresponding to one of the phases of the machine. For example, an electric machine may be configured to operate as an alternator having a desired number of stator windings, where each stator winding corresponds to one of the phases of the multiphase electric machine. During operation of the alternator, the stator provides an alternating current signal to the first phase terminal. In response to the alternating current signal, the electronic module determines whether the peak-to-peak magnitude of the alternating current signal is at least equal to a threshold level, and if so, the electronic module may control the MOSFET half-bridge circuitry to provide a direct current voltage at the supply voltage terminal.

[0009] For example, an embodiment of the electronic module may include magnitude detector circuitry configured to receive the alternating current signal and determine whether the peak-to-peak magnitude of the alternating current signal is at least equal to a threshold level. The threshold level corresponds to the magnitude of the alternating current signal at which the rotor of the alternator has sufficient rotational speed to rectify the alternating current signal.

[0010] In some embodiments, the magnitude detector circuitry determines the magnitude of the peak-to-peak voltage generated by alternating current received at a load. In other

embodiments, the magnitude detector circuitry is configured as a peak detector circuit that can integrate the alternating current signal to generate a control voltage which governs the operation of a switch circuit. The switch circuit may be configured to provide a turn-on supply voltage from a supply voltage source so long as the magnitude of the peak-to-peak voltage generated by the alternating current is at least equal to a threshold level. As an example, a supply voltage may be provided by a battery in communication with the switch circuit. Closing the switch circuit may permit the supply voltage source to provide a turn-on supply voltage to charge pump oscillator circuitry which can generate switch control signals to govern the operation of charge pump circuitry configured to generate a boost supply voltage. The MOSFET half-bridge control circuitry may be configured to receive both the turn-on supply voltage and the boost supply voltage. The MOSFET half-bridge control circuitry may be enabled upon receipt of the turn-on supply voltage and the boost supply voltage. The MOSFET half-bridge control circuitry may be configured to govern the operation of MOSFET half-bridge circuitry, which rectifies the alternating current signal to provide the supply voltage as an output on the supply voltage terminal of the electronic module. The supply voltage provided by the MOSFET half-bridge circuitry may charge the supply voltage source. The magnitude detector circuitry may open the switch circuit in response to determining that the magnitude of the peak-to-peak voltage generated by the alternating current is less than a threshold level. Opening the switch circuit deprives the charge pump oscillator circuitry and the MOSFET half-bridge control circuitry of the turn-on supply voltage, resulting in disablement of the charge pump oscillator circuitry and the MOSFET half-bridge control circuitry.

[0011] Some embodiments of an electric machine include magnitude detector circuitry and MOSFET half-bridge circuitry configured to generate a supply voltage as a function of a phase signal generated by a stator. The magnitude detector circuitry may receive a phase signal from a stator winding of a stator. The magnitude detector circuitry includes a switch control output configured to assert a switch control signal in response to the magnitude of the phase signal substantially equaling at least a turn-on threshold level. The MOSFET half-bridge circuitry rectifies the first phase signal as a function of the assertion of the switch control signal.

[0012] In a method for rectifying an alternating current signal according to the present disclosure, the electric machine determines whether the magnitude of an alternating current signal generated by a stator and received from a stator winding is at least substantially equal to a turn-on threshold level. In response to a determination that the magnitude of the alternating current signal is at least equal to the turn-on threshold level, the alternating current is rectified to generate a supply voltage.

[0013] The present disclosure provides a system for rectifying an alternating current signal. The system includes MOSFET half-bridge circuitry and magnitude detector circuitry. The magnitude detector circuitry is configured to determine whether the peak magnitude of a phase signal is at least equal to a turn-on threshold level. The magnitude detector circuitry is also configured to enable the MOSFET half-bridge circuitry to rectify the phase signal in response to the peak magnitude of the phase signal at least equaling the turn-on threshold level.

[0014] The present disclosure also provides a method for rectifying an alternating current signal including: receiving an alternating current signal from a stator; determining whether the magnitude of the alternating current signal is at least substantially equal to a turn-on threshold level; and, in response to a determination that the magnitude of the alternating current signal is at least equal to the turn-on threshold level, rectifying the alternating current signal to generate a supply voltage.

[0015] A further aspect of the disclosed method is that it also includes, in response to a determination that the magnitude of the alternating current signal is less than the turn-on threshold level, disabling rectification of the alternating current signal to generate a supply voltage.

[0016] An additional aspect of the disclosed method is that the determination of whether the magnitude of the alternating current signal is at least equal to the turn-on threshold level includes: generating a pulse signal as a function of the magnitude of the alternating current signal; integrating the pulse signal to generate a switch control signal; and providing a turn-on supply voltage and a boost supply voltage to a MOSFET half-bridge control circuitry in response to an assertion of the switch control signal.

[0017] Another aspect of the disclosed method is that it also includes disabling the turn-on supply voltage and the boost supply voltage in response to a de-assertion of the switch control signal.

[0018] Another aspect of the disclosed method is that, in response to the determination that the magnitude of the alternating current signal is at least equal to the turn-on threshold level, rectifying the alternating current signal to generate the supply voltage includes generating a charge pump control signal in response to the determination that the magnitude of the alternating current signal is at least equal to the turn-on threshold level. The method may also include generating a boost supply voltage in response to the charge pump control signal. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] The above-mentioned aspects and other characteristics and advantages of an apparatus and/or method according to the present disclosure will become more apparent and will be better understood by reference to the following description of exemplary embodiments taken in conjunction with the accompanying drawings, wherein:

[0020] FIG. 1 depicts a cross-sectional view of an electric machine;

[0021] FIG. 2 depicts an isometric view of a frame assembly and a cover of the electric machine depicted in FIG. 1 ;

[0022] FIG. 3 depicts an isometric view of a frame assembly of the electric machine depicted in FIGS. 1 and 2;

[0023] FIG. 4 depicts an embodiment of the frame assembly of an electric machine that is similar to the frame assembly depicted in FIG. 3;

[0024] FIG. 5 depicts an isometric view of an embodiment of a frame assembly of an electric machine configured to operate cooperatively as a three phase electric machine;

[0025] FIG. 6 depicts a system diagram of an embodiment of an electronic module having MOSFET half-bridge circuitry configured to rectify one or more phase signals from a stator of an electric machine;

[0026] FIG. 7 depicts an embodiment of a portion of the control board depicted in FIG. 6; and

[0027] FIG. 8 depicts an embodiment of the MOSFET half-bridge control circuitry and the MOSFET half-bridge circuitry of FIG. 6.

[0028] Corresponding reference characters indicate corresponding parts throughout the several views. Although the drawings represent embodiments of the disclosed apparatus and method, the drawings are not necessarily to scale or to the same scale and certain features may be exaggerated or omitted in order to better illustrate and explain the present disclosure. Moreover, in accompanying drawings that show sectional views, cross-hatching of various sectional elements may have been omitted for clarity. It is to be understood that this omission of cross- hatching is for the purpose of clarity in illustration only. DETAILED DESCRIPTION OF EXEMPLARY EMBODIMENTS

[0029] The embodiments of the present invention described below are not intended to be exhaustive or to limit the invention to the precise forms disclosed in the following detailed description. Rather, the embodiments are chosen and described so that others skilled in the art may appreciate and understand the principles and practices of the present invention.

[0030] FIG. 1 depicts a cross-sectional view of an exemplary embodiment of an electric machine 20 that is an alternator. Other, alternative embodiments of the electric machine 20 may be configured as electric motors, or as motor/generator apparatuses controlled to operate in an alternator mode of operation or an electric motor mode of operation. As shown, the electric machine 20 includes a cover 22, a frame assembly 24, and a stator housing 26. The cover 22 is configured to mate with the frame assembly 24, which is attached to the stator housing 26 with a first fastener 28 and a second fastener 30. The stator housing 26 has an interior stator housing surface 32 and an exterior stator housing surface 34 which may join to form edges defining stator housing ventilation apertures 36.

[0031] The electric machine 20 includes a stator 38 having a stator core 40 and stator windings 42 having end turns 44 that extend beyond the stator core 40. The electric machine 20 also includes a rotor 46 that is fixed to a shaft 48 for rotation therewith, and a fan 50 located between the frame assembly 24 and the rotor and rotatable in unison with the rotor and the shaft. The fan 50 may be configured as a centrifugal fan.

[0032] Referring to FIGS. 2 and 3, the frame assembly 24 includes a rigid frame 52 formed from a metallic material such as a casting of aluminum or an aluminum alloy. The frame 52 has an exterior frame surface 56 and an interior frame surface 58 which join to form the edges 60 of frame ventilation apertures 54. The frame ventilation apertures 54 may provide passages through which cooling air may be exhausted by the fan 50 from the interior region of the electric machine 20.

[0033] The cover 22 has an interior cover surface 62 and an exterior cover surface 64 which join to form the peripheral edge 66 of a supply terminal opening 68. The machine 20 includes a supply terminal assembly 70 having a supply voltage post 72 which extends through a supply terminal opening 68. The supply voltage post 72 is formed from a rigid, electrically conductive material such as steel. As shown, the supply voltage post 72 has threads 76 configured to threadedly receive and have electrical contact with an annular fastener 74 formed from a rigid, suitably conductive material. The annular fastener 74 is disk-shaped and has opposite, substantially flat surfaces 78. Referring to FIG. 1, the upwardly facing flat surface 78 provides an electrical contact surface for an electrical cable 82 that is secured to the supply terminal assembly 70 with a nut. The fastener 74 is configured to provide surface-to-surface contact with the cable to increase the area through which they are in electrical communication, relative to mere line-to-line contact, which decreases impedance between the supply terminal assembly 70 and the cable.

[0034] When the electric machine 20 is configured as a generator or an alternator, the electric machine 20 produces a supply voltage on the supply voltage post 72. In such case, electric machine 20 converts mechanical torque applied to the rotor 46 to supply voltage at the supply terminal assembly 70. The supply voltage may be distributed to various devices via the electrical cable 82 coupled to the supply voltage post 72. Alternatively, some embodiments of the electric machine 20 may be configured to operate as an electrical motor. In such case, a supply voltage is provided via the electrical cable 82 to the supply voltage post 72, and is subsequently directed to the stator windings, which magnetically induces a mechanical torque on the rotor and its shaft.

[0035] Referring to FIG. 2, some of the frame ventilation apertures 54 may be configured to provide frame fastener passages 110 that receive fasteners similar to the first and second fasteners 28, 30 depicted in FIG. 1, by which the frame 52 and the stator core 40 may be secured together. The frame 52 may also include mounting lugs 116 (one of which is shown in the Figures). Referring to FIG. 3, each mounting lug 116 has a through hole 118 which may be configured to receive a bolt (not shown) for securing the machine 20 to mounting bracketry (not shown). The mounting bracketry, which may be attached to a vehicle engine if the machine 20 is an alternator, abuts the mounting surfaces 120 of the lugs 116 located about the through holes 118. In some embodiments, the interior surface 122 of one or more through holes 118 is tapped to threadedly engage a bolt received therein for securing the machine 20 to its bracketry.

[0036] The supply terminal assembly 70 includes a stand 124 configured to affix the supply voltage post 72. The stand 124 holds the supply voltage post 72 in relationship to an electrical buss 126. In some embodiments of the supply terminal assembly 70, the supply voltage post 72 may be integrated into the stand 124. As an example, the supply terminal assembly 70 may include a stand 124 made of an electrically non-conductive material. For example, the stand 124 may be made of a nylon or glass-filled nylon material, and formed by an injection molding process. Advantageously, in the case where the stand 124 is formed with an electrically non- conductive material, the supply voltage post 72 may be inherently electrically isolated from the frame 52 due to the stand 124 being formed from an electrically non-conductive material, thus avoiding the need for an electrical insulator between the supply voltage post 72 and the stand 124 or the frame 52 and the stand 124, which would otherwise be provided.

[0037] FIGS. 3 and 4 depict similar embodiments of frame assembly 24 of electric machine 20. The electric machine 20 may include frame assembly 24 having a stator lead wire assembly 230. The stator lead wire assembly 230 may receive stator lead wires 106 from stator 38. The stator lead wire assembly 230 may include a base 232 configured to mount to frame 52. The stator lead wire assembly 230 may incorporate a plurality of sleeves 234, each of which is associated with a respective one of stator lead wires 106. The sleeves 234 may extend partially through some of frame ventilation apertures 54. Each sleeve 234 and base 232 may be formed from an electrically insulating material. The stator lead wires 106 may be fed from the interior region of frame assembly 24 through sleeves 234 of stator lead wire assembly 230. As a non- limiting example, stator lead wire assembly 230 may be configured to receive a first stator lead wire 236, a second stator lead wire 238, a third stator lead wire 240, a fourth stator lead wire 242, a fifth stator lead wire 244, and a sixth stator lead wire 246, which correspond to stator lead wires 106 provided from stator windings 42 to form a six phase electric machine. The first stator lead wire 236, second stator lead wire 238, third stator lead wire 240, fourth stator lead wire 242, fifth stator lead wire 244, and sixth stator lead wire 246 may exit a respective sleeve 234 to permit connection to electronic assemblies 102, as also depicted in FIG. 3.

[0038] Continuing with FIG. 4, electronic assemblies 102 may include a first electronic module 248, a second electronic module 250, and a third electronic module 252. As a non- limiting example, each of the first electronic module 248, the second electronic module 250, and the third electronic module 252 may include a first phase terminal 254, a second phase terminal 256, and a supply voltage terminal 258. In some embodiments, first phase terminal 254 and second phase terminal 256 of each of first electronic module 248, second electronic module 250, and third electronic module 252 may be coupled to one of first stator lead wire 236, a second stator lead wire 238, a third stator lead wire 240, a fourth stator lead wire 242, a fifth stator lead wire 244, and a sixth stator lead wire 246. For example, a first phase lead 260 may couple first stator lead wire 236 to second phase terminal 256 of third electronic module 252. A second phase lead 262 may couple second stator lead wire 238 to first phase terminal 254 of third electronic module 252. A third phase lead 264 may couple third stator lead wire 240 to first phase terminal 254 of first electronic module 248. A fourth phase lead 266 may couple fourth stator lead wire 242 to second phase terminal 256 of first electronic module 248. A fifth phase lead 268 may couple fifth stator lead wire 244 to second phase terminal 256 of second electronic module 250. And, a sixth phase lead 270 may couple sixth stator lead wire 246 to first phase terminal 254 of second electronic module 250. Each phase lead of the stator lead wire assembly 230 is formed from a respective single, elongate piece of an electrically conducive metallic material such as copper or a copper alloy. The single conductor may be an extruded or drawn wire or stamped sheet material. The single conductor material may be substantially circular (including elliptical) or, alternatively, substantially rectangular (including square) or hexagonal in cross-section.

[0039] Each of first phase terminal 254 and second phase terminal 256 may be coupled to a corresponding first MOSFET half-bridge circuit 446 and second MOSFET half-bridge circuit 448, which are depicted in FIG. 8. As will be described below, first MOSFET half-bridge circuit 446 and second MOSFET half-bridge circuit 448 may be configured to rectify the alternating current signal to generate a supply voltage. Each corresponding MOSFET half- bridge circuit may provide the supply voltage to supply voltage terminal 258. In turn, each supply voltage terminal 258 provides the supply voltage via the supply buss 126 to the supply terminal assembly 70. For example, as discussed below, a control board may be mounted within each of the first electronic module 248, the second electronic module 250, and the third electronic module 252 to independently control the operation of each of the first MOSFET half- bridge circuit 446 and the second MOSFET half-bridge circuit 448. In this fashion, referring to FIG. 8, MOSFET half-bridge control circuitry 420 of each of the first electronic module 248, the second electronic module 250, and the third electronic module 252 controls a first MOSFET half-bridge circuit 446 to rectify the alternating current signal received on the first phase terminal 254, and a second MOSFET half-bridge circuit 448 to rectify the alternating current signal received on the second phase terminal 256.

[0040] In other embodiments, each of the first electronic module 248, the second electronic module 250, and the third electronic module 252 may each have only one phase terminal and a corresponding MOSFET half-bridge circuit (not shown). In other embodiments, the first electronic module 248, the second electronic module 250, and the third electronic module 252 may each include three or more phase terminals, and one MOSFET half-bridge circuit (not shown) for each of the three or more phase terminals. For example, in some embodiments, the electric machine 20 may be configured to operate as a three phase machine. In that case, some embodiments of the first electronic module 248, the second electronic module 250, and the third electronic module 252 may include only one phase terminal and two or more MOSFET half- bridge circuits (not shown) coupled in parallel to the one phase terminal. In this case, each of the MOSFET half-bridge circuits may operate cooperatively in parallel to generate the supply voltage on the supply voltage terminal 258. As a result, the rectifying resistance of each of the first electronic module 248, the second electronic module 250, and the third electronic module 252 may be reduced. For example, for the case where two MOSFET half-bridge circuits operate cooperatively in parallel to generate the supply voltage on the supply voltage terminal 258, the rectifying resistance is halved. Alternatively, some embodiments of the electric machine 20 may have only a single electronic assembly 102 having three phase terminals and a corresponding MOSFET half-bridge circuit (not shown) associated with each of the three phase terminals (not shown). In this case, each of the three phase terminals may be configured to respectively rectify one of the alternating current signal produced by the stator windings 42.

[0041] Figure 5 depicts an embodiment of a frame assembly 24 A of an electric machine 20 that includes the first electronic module 248, the second electronic module 250, and the third electronic module 252 configured to operate cooperatively as a three phase electric machine, which is described with continuing reference to Figures 1-4. Frame assembly 24 A includes stator lead wire assembly 230A having base 232A and a plurality of above-mentioned sleeves 234, one for each stator lead wire. In this case, there are only three stator lead wires, and the first phase terminal 254 and the second phase terminal 256 of each of the first electronic module 248, the second electronic module 250, and the third electronic module 252 may be coupled such that each MOSFET half-bridge circuit operates cooperatively to rectify a respective one of the three phase signals of the electric machine 20.

[0042] For example, an electric machine 20 having frame assembly 24A includes a stator lead wire assembly 230A configured to receive a first stator lead wire 236, a second stator lead wire 238, a third stator lead wire 240 A, A first phase lead 260 A may couple the first phase terminal 254 and the second phase terminal 256 of the third electronic module 252 to the first stator lead wire 236. A second phase lead 262A may couple the first phase terminal 254 and the second phase terminal 256 of the first electronic module 248 to the second stator lead wire 238. The third phase lead 264A may couple the first phase terminal 254 and the second phase terminal 256 of the second electronic module 250 to the third stator lead wire 240 A. Each phase lead of the stator lead wire assembly 23 OA is formed from a respective single, elongate piece of an electrically conducive metallic material such as copper or a copper alloy. The single conductor may be an extruded or drawn wire or stamped sheet material. The single conductor material may be substantially circular (including elliptical) or, alternatively, substantially rectangular

(including square) or hexagonal in cross-section.

[0043] Each of the first electronic module 248, the second electronic module 250, and the third electronic module 252 may include a first MOSFET half-bridge circuit 446 associated with the first phase terminal 254 and a second MOSFET half-bridge circuit 448 associated with the second phase terminal 256. The first MOSFET half-bridge circuit 446 and the second MOSFET half-bridge circuit 448 of each of the first electronic module 248, the second electronic module 250, and the third electronic module 252 may operate in parallel to rectify the alternating current signal received respectively from the first stator lead wire 236, the second stator lead wire 238, and the third stator lead wire 240A.

[0044] Each of the first phase lead 260A, the second phase lead 262A, and the third phase lead 264A includes an extended j -loop 272A configured to be resistively welded to both the first phase terminal 254 and the second phase terminal 256 of the electronic module 248, 250, 252 to which it is respectively connected. The extended j -loops 272A which, as shown, may differ in configuration between the their respective phase leads 260A, 262A, 264A, each include a first conductor portion 274A and a second conductor portion 276A unitarily formed of a conductive material. The first conductor portion 274A and the second conductor portion 276A are configured to contact the first phase terminal 254 and the second phase terminal 256 of each electronic module 248, 250, 252. In some embodiments, the first phase terminal 254 and the second phase terminal 256 of an electronic module 248, 250, 252 are disposed between the first conductor portion 274A and the second conductor portion 276A of the respective phase lead 260A, 262A, 264A. The weld heads of a resistive welding machine (not shown) may contact the first conductor portion 274A and the second conductor portion 276A of a phase lead to mechanically place the first phase terminal 254 and the second phase terminal 256 of the associated electronic module in contact with that phase lead. For example, in some

embodiments, the weld heads (not shown) may pinch the first phase terminal 254 and the second phase terminal 256 of an electronic module between the first conductor portion 274A and the second conductor portion 276A of the associated phase lead. Thereafter, electrical energy may be provided by the resistive welding machine to join the first and second phase terminals 254, 256 of the electronic module to the phase lead. In some cases, the weld heads (not shown) may contact the first and second conductor portions 274A, 276A a midpoint between the first and second phase terminals 254, 256 of the electronic module. The electrical energy may be applied by the weld heads to the first and second portions 274A, 276A simultaneously to resistively weld the first and second phase terminals 254, 256 of an electronic module 248, 250, 252 to their associated phase lead 260A, 262A, 264A.

[0045] FIG. 6 depicts an exemplary embodiment of an electronic module 400 representative of one of the first electronic module 248, the second electronic module 250, and the third electronic module 252. Electronic module 400 may be configured to rectify at least one of the alternating current signals generated by stator 38. For example, electronic module 400 may include a first phase terminal 254 configured to receive a first phase signal 426, a second phase terminal 256 configured to receive a second phase signal 428, and a supply voltage terminal 258 configured to be in communication with supply voltage device 402. Supply voltage device 402 may be configured to provide a supply voltage 404 to electronic module 400. For example, supply voltage device 402 may provide supply voltage 404 to electronic module 400 while electronic module 400 is in a standby state of operation. In addition, supply voltage device 402 may receive a charging voltage 406 from electronic module 400. For example, electronic module 400 may provide charging voltage 406 to supply voltage device 402 while electronic module 400 is in an active mode of operation. Supply voltage terminal 258 is typically formed as a two-terminal structure having a positive and a negative leg, whereby the charging voltage 406 may be present on both positive and negative terminals. Electronic module 400 may include a control board 408 and a power board 410. Power board 410 may include a ceramic substrate holding electronic devices for rectifying at least one of the alternating current signals generated by stator 38.

[0046] As an example, stator 38 may include a number of stator windings that generate a corresponding number of alternating current signals. For example, stator 38 may generate the above-mentioned first phase signal 426 and second phase signal 428, and other phase signals 430 in response to a rotation of rotor 46. Illustratively, for the case where stator 38 is configured as a six -phase electric machine, the other phase signals 430 may include a third phase signal, a fourth phase signal, a fifth phase signal, and a sixth phase signal (not shown).

[0047] Control board 408 may include phase magnitude detector circuitry 412, switch circuitry 414, charge pump oscillator circuitry 416, charge pump circuitry 418, and the above- mentioned MOSFET half-bridge control circuitry 420. Phase magnitude detector circuitry 412 may be configured to minimize a leakage current drawn from supply voltage device 402 while electrical machine 20 is operating in a standby state. In addition, phase magnitude detector circuitry 412 may be further configured to energize charge pump circuitry 418 and enable MOSFET half-bridge control circuitry 420.

[0048] In some embodiments, phase magnitude detector circuitry 412 may be configured to receive one of the alternating current signals generated by the stator 38. Phase magnitude detector circuitry 412 may determine whether the magnitude of the alternating current signal is at least equal to a threshold level. Based on a determination that the magnitude of the alternating current signal is at least equal to a threshold level, phase magnitude detector circuitry 412 may generate a switch control signal 424, which is provided to switch circuitry 414. As an example, phase magnitude detector circuitry 412 receives first phase signal 426, detects the magnitude of first phase signal 426, and generates switch control signal 424 when the magnitude of first phase signal 426 is at least equal to a threshold level voltage.

[0049] As depicted in FIG. 7, some embodiments of phase magnitude detector circuitry 412 may include an inverting amplifier 438 and integrator circuitry 440. Inverting amplifier 438 follows the phase pulses when the peak voltage of the phase signal is greater than a predetermined threshold. A pulsing signal 442 may be asserted in response to first phase signal 426 having a magnitude that exceeds a threshold level voltage. Pulsing signal 442 may be de- asserted in response to first phase signal 426 having a magnitude that falls below the threshold level. The pulsing signal may be integrated to maintain a switch control signal 424 that is substantially constant so long as the magnitude of the first phase signal 426 repeatedly exceeds the threshold level voltage for a minimum time period.

[0050] Returning to Figure 6, some embodiments of the phase magnitude detector circuitry 412 may assert the switch control signal 424 based on a determination that the magnitude of the first phase signal 426 is at least equal to one -half of the peak-to-peak voltage swing developed during normal operation of the stator 38. Alternatively, in embodiments where the supply voltage device 402 is configured to have a storage voltage substantially equal to 12 V, the threshold level voltage may be substantially near or about between 7.0 V and 8.5 V.

[0051] In some embodiments, the phase magnitude detector circuitry 412 compares the magnitude of the first phase signal 426 to a threshold level. Based on a determination that the magnitude of the first phase signal 426 is at least equal to the threshold level, the phase magnitude detector circuitry 412 asserts a switch control signal 424 to activate the switch circuitry 414. Upon activation, the switch circuitry 414 switchably provides a turn-on supply voltage 432 derived from the supply voltage 404 to the charge pump oscillator circuitry 416 and the MOSFET half-bridge control circuitry 420.

[0052] Upon receipt of turn-on supply voltage 432, charge pump oscillator circuitry 416 commences to generate a charge pump control signal 434. Charge pump oscillator circuitry 416 may include an oscillator or it may be structured for receiving an oscillation signal, and issues charge pump control signal 434 to the charge pump circuitry 418 in response to the charge pump oscillator circuitry 416 receiving an oscillation signal. Timing and oscillation frequency may be adjusted according to a resistor-capacitor derived time constant. In some embodiments, the charge pump control signal 434 is a charge pump clock signal. In response to the switching action of charge pump control signal 434, charge pump circuitry 418 switchably charges and discharges at least one flying capacitor to provide a boost supply voltage 436 to MOSFET half- bridge control circuitry 420. [0053] MOSFET half-bridge control circuitry 420 may receive turn-on supply voltage 432, boost supply voltage 436, and one or more phase signals to be rectified, to generate charging voltage 406. As a non-limiting example, MOSFET half-bridge circuitry 422 may receive first phase signal 426 and second phase signal 428. In response to receipt of turn-on supply voltage 432, boost supply voltage 436, first phase signal 426 and second phase signal 428, MOSFET half-bridge control circuitry 420 may enable output circuitry (not depicted) configured to control the operation of MOSFET half-bridge circuitry 422. As an example, in some embodiments, MOSFET half-bridge control circuitry 420 may include open collector outputs configured to drive MOSFET half-bridge circuitry 422. Boost supply voltage 436 and turn-on supply voltage 432 may be provided to pull-up resistors to enable operation of the open collector outputs of MOSFET half-bridge control circuitry 420. MOSFET half-bridge control circuitry 420 may provide MOSFET control signals 444 to govern the operation of MOSFET half-bridge circuitry 422.

[0054] As depicted in FIG. 8, power board 410 includes MOSFET half-bridge circuitry 422. MOSFET half-bridge circuitry 422 may be configured to rectify one or more alternating current signals generated by stator 38 as a function of MOSFET control signals 444. As an example, MOSFET half-bridge circuitry 422 may include a first MOSFET half-bridge circuit 446 configured to rectify first phase signal 426 to generate the charging voltage 406. MOSFET half- bridge circuitry 422 may also include a second MOSFET half-bridge circuit 448 configured to rectify second phase signal 428 to generate charging voltage 406. MOSFET half-bridge control circuitry 420 may be configured to control operation of first MOSFET half-bridge circuit 446 as a function of first phase signal 426. Similarly, MOSFET half-bridge control circuitry 420 may be configured to control operation of second MOSFET half-bridge circuit 448 as a function of second phase signal 428.

[0055] FIG. 7 depicts an embodiment of phase magnitude detector circuitry 412 including inverting amplifier 438 configured to generate a pulsing signal 442 in response to first phase signal 426, and integrator circuitry 440 configured to integrate pulsing signal 442 generated by inverting amplifier 438 to provide a switch control signal 424 to switch circuitry 414. For example, inverting amplifier 438 may include a first resistor 450 (Rl), a second resistor 452 (R2), a first capacitor 454 (CI), a first zener diode 456 (Zl), and a first transistor 458 (Ql). The first resistor 450 (Rl) may include a first terminal in communication with stator 38. First resistor 450 (Rl) may receive a first phase signal 426 from one of the stator windings of stator 38, which provides a phase voltage to the first terminal of first resistor 450 (Rl). First capacitor 454 (CI) may be coupled between a second terminal of first resistor 450 (Rl) and a reference voltage 460. In some embodiments, reference voltage 460 may be ground.

[0056] The first zener diode 456 (Zl) and the second resistor 452 (R2) may be coupled in series between the second terminal of the first resistor 450 (Rl) and the reference voltage 460. In particular, the first zener diode 456 (Zl) may include a cathode in communication with the second terminal of the first resistor 450 (Rl) and an anode in communication with the first terminal of the second resistor 452 (R2). The second terminal of the second resistor 452 (R2) may be in communication with the reference voltage 460. The first transistor 458 (Ql) may include a control terminal 462 in communication with the anode of the first zener diode 456 (Zl) and the first terminal of the second resistor 452 (R2). The first transistor 458 (Ql) may also include a non-inverting output 464 in communication with the reference voltage 460 and an inverting output 466 configured to provide the pulsing signal 442 in response to the first phase signal 426.

[0057] In addition, the integrator circuitry 440 may include a second capacitor 470 (C2), a third resistor 472 (R3), and a fourth resistor 474 (R4) configured to provide a switch control signal 424 to the switch circuitry 414. The third resistor 472 (R3) may include a first terminal configured to receive the supply voltage 404 and a second terminal in communication with a first terminal of the fourth resistor 474 (R4). The fourth resistor 474 (R4) may include a second terminal in communication with the inverting output 466 of the first transistor 458 (Ql) and a first terminal of the second capacitor 470 (C2). The second terminal of the second capacitor 470 (C2) may be in communication with the reference voltage 460. The phase magnitude detector circuitry 412 may provide a voltage level at the second terminal of the third resistor 472 (R3) as a switch control signal 424.

[0058] The switch circuitry 414 may include a second transistor 476 (Q2) having a control terminal 478 in communication with the second terminal of the third resistor 472 (R3), and configured to receive the switch control signal 424. The second transistor 476 (Q2) may include a non-inverting output 480 configured to receive the supply voltage 404 and an inverting output 482 in communication with a first terminal of a fifth resistor 486 (R5). A third capacitor 488 (C3) and a second zener diode 490 (Z2) may be coupled in parallel between the second terminal of the fifth resistor 486 (R5) and the reference voltage 460. The combination of the fifth resistor 486 (R5) and the second zener diode 490 (Z2) may provide a degree of overvoltage protection by absorbing excess voltage provided from the supply voltage 404 through the second transistor 476 (Q2) in a fault condition. An example of a fault condition may include a load dump due to a sudden interruption of the communication between the supply voltage device 402 and the electronic module 400.

[0059] A turn-on supply voltage 432 may be developed across the third capacitor 488 (C3) in response to the second transistor 476 (Q2) operating in an on state. When the second transistor 476 (Q2) is in the on state, the turn-on supply voltage 432 may substantially equal the supply voltage 404. When the second transistor 476 (Q2) is in the off state, the turn-on supply voltage 432 may substantially equal the reference voltage 460. The turn-on supply voltage 432 may be provided to the charge pump oscillator circuitry 416 and the MOSFET half-bridge control circuitry 420.

[0060] Operationally, the first terminal of the first resistor 450 (Rl) may receive the first phase signal 426. The first resistor 450 (Rl) and the first capacitor 454 (CI) may filter the first phase signal 426. The first zener diode 456 (Zl) may operate in the break down mode of operation as a function of the zener break down voltage. For example, the first zener diode 456 (Zl) may have a zener break down voltage substantially equal to 7.5 volts. The current passing through the first zener diode 456 (Zl) may generate a control voltage across the second resistor 452 (R2). The control voltage may appear between the control terminal 462 of the first transistor 458 (Ql) and the non-inverting output 464 of the first transistor 458 (Ql).

[0061] So long as the magnitude of the first phase signal 426 is less than the threshold level voltage, the first transistor 458 (Ql) remains in an off state. The second capacitor 470 (C2) may be charged from the supply voltage 404 through a series resistance formed by the third resistor 472 (R3) and the fourth resistor 474 (R4). As a result, the switch control signal 424 may substantially equal the supply voltage 404, which turns off the second transistor 476 (Q2). In response to the first phase signal 426 having a magnitude that is less that the threshold level voltage, the MOSFET half-bridge control circuitry 420 is disabled, which in turn disables the MOSFET half-bridge circuitry 422.

[0062] For example, the first transistor 458 (Ql) may generate the pulsing signal 442 as a function of the first phase signal 426 and a time constant formed by the second capacitor 470 (C2) and the series resistance formed by the third resistor 472 (R3) and the fourth resistor 474 (R4). The first transistor 458 (Ql) may become active once the magnitude of the first phase signal 426 at least equals a threshold level voltage, which may substantially equal the sum of the zener break down voltage and a turn-on voltage of the first transistor 458 (Ql). In response to the first phase signal 426 having a voltage level at least equal to the threshold voltage level, the first transistor 458 (Ql) may sink current at the inverting output 466 to discharge the second capacitor 470 (C2). Simultaneously, the first transistor 458 (Ql) may sink current through the third resistor 472 (R3) and the fourth resistor 474 (R4). When the magnitude of the first phase signal 426 is less than the threshold voltage level, the first transistor 458 (Ql) turns off, and the second capacitor 470 (C2) may begin recharging. The capacitance of the second capacitor 470 (C2) in combination with the combined resistance of the third resistor 472 (R3) and the fourth resistor 474 (R4) may form a time constant that governs the magnitude of the switch control signal 424 while the first transistor 458 (Ql) is transitioning between the on state and the off state. When the second capacitor 470 (C2) is fully discharged, the third resistor 472 (R3) and the fourth resistor 474 (R4) form a voltage divider to produce the switch control signal 424, and the second transistor 476 (Q2) may be turned on to provide the turn-on supply voltage 432. The second transistor 476 (Q2) may remain in the on state of operation as long as the voltage across the third resistor 472 (R3) has a magnitude at least equal to the turn-on voltage of the second transistor 476 (Q2).

[0063] The charge pump oscillator circuitry 416 may include an amplifier circuit 492 configured to generate a charge pump control signal 434 in response to receiving the turn-on supply voltage 432 from the switch circuitry 414. For example, the amplifier circuit 492 may be powered by the turn-on supply voltage 432. In some embodiments, amplifier circuit 492 may have an open collector output. In this case, the charge pump oscillator circuitry 416 may include a sixth resistor 494 (R6) coupled between the turn-on supply voltage 432 and an output of the amplifier circuit 492. In addition, the charge pump oscillator circuitry 416 may include a seventh resistor 496 (R7) and an eighth resistor 498 (R8) coupled in series between the turn-on supply voltage 432 and the reference voltage 460. The seventh resistor 496 (R7) and the eighth resistor 498 (R8) may form a resistive divider network coupled to the non-inverting input of the amplifier circuit 492, which sets a threshold voltage at which the output of the amplifier circuit 492 may switch between an on state and an off state. The charge pump oscillator circuitry 416 may further include a ninth resistor 500 (R9) coupled between the output of amplifier circuit 492 and the inverting input of the amplifier circuit 492. In addition, a fourth capacitor 502 (C4) may be coupled between the inverting input of the amplifier circuit 492 and the reference voltage 460. A tenth resistor 504 (R10) may be coupled between the output of the amplifier circuit 492 and the non-inverting input of the amplifier circuit 492. Operationally, the tenth resistor 504 (R10) may provide hysteresis to ensure the stability of charge pump oscillator circuitry 416.

[0064] In response to receiving the turn-on supply voltage 432 substantially equal to the supply voltage 404, the fourth capacitor 502 (C4) may be substantially discharged such that the inverting input of the amplifier circuit 492 receives an input voltage substantially equal to the reference voltage 460. The resistive divider network formed by the seventh resistor 496 (R7) and the eighth resistor 498 (R8) may provide the non-inverting input of the amplifier circuit 492 an input voltage greater than the reference voltage 460.

[0065] As a result, the output of the amplifier circuit 492 may be turned off to set the charge pump control signal 434 substantially equal to the turn-on supply voltage 432. The fourth capacitor 502 (C4) may be charged through the eighth resistor 498 (R8) until the voltage at the inverting input of the amplifier circuit 492 is at least equal to the input voltage received at the non-inverting input of the amplifier circuit 492. In response to the input voltage received at the inverting input of the amplifier circuit 492 being at least equal to the input voltage receive at the non-inverting input of the amplifier circuit 492, the output of the amplifier circuit 492 may turn- on to sink current through the sixth resistor 494 (R6), which sets the charge pump control signal 434 substantially equal to the reference voltage 460. The resistance of the tenth resistor 504 (R10) is placed in parallel with the resistance of the eighth resistor 498 (R8) to downwardly adjust the input voltage received by the non-inverting input of the amplifier circuit 492.

[0066] While the output of the amplifier circuit 492 is substantially equal to the reference voltage 460, the fourth capacitor 502 (C4) may discharge through the eighth resistor 498 (R8). In response to the voltage across the fourth capacitor 502 (C4) falling below the input voltage received at the non-inverting input of the amplifier circuit 492, the output of the amplifier circuit 492 may turn off to permit the sixth resistor 494 (R6) to set the charge pump control signal 434 substantially equal to the turn-on supply voltage 432. The rate of oscillation of the charge pump control signal 434 may be set as a function of the hysteresis provided by the ninth resistor 500 (R9) and the time constant formed by the combination of the fourth capacitor 502 (C4) and the eighth resistor 498 (R8).

[0067] The charge pump circuitry 418 may include a fifth capacitor 506 (C5) configured to operate as a flying capacitor as a function of the charge pump control signal 434. Some embodiments of the charge pump circuitry 418 may include an eleventh resistor 508 ( Rl 1) having a first terminal configured to receive the charge pump control signal 434 and a second terminal in communication with a first terminal of a twelfth resistor 510 (R12) and the control terminal of a third transistor 514 (Q3). The second terminal of twelfth resistor 510 (R12) and the non-inverting output of the third transistor 514 (Q3) may be in communication with the reference voltage 460. The inverting output of the third transistor 514 (Q3) may be configured to provide a switching signal 516 to the control input of a fourth transistor 518 (Q4) via a thirteenth resistor 520 (R13) and a fourteenth resistor 522 (R14) coupled in series to the supply voltage 404. The first terminal of the thirteenth resistor 520 (R13) and the non-inverting output of the fourth transistor 518 may be in communication with the supply voltage 404. The second terminal of the thirteenth resistor 520 (R13) and the first terminal of the fourteenth resistor 522 (R14) may be coupled to the control input of the fourth transistor 518 (Q4). The second terminal of the fourteenth resistor 522 (R14) may be in communication with the inverting output of the third transistor 514 (Q3). The inverting output of the fourth transistor 518 (Q4) may be coupled to the reference voltage 460 via a fifteenth resistor 524 (R15). The inverting output of the fourth transistor 518 (Q4) may also be coupled to the control input of a fifth transistor 526 (Q5). The non-inverting input of the fifth transistor 526 (Q5) may be coupled to the supply voltage 404. The inverting output of fifth transistor 526 (Q5) may be in communication with a second terminal of the fifth capacitor 506 (C5) and inverting output of a sixth transistor 528 (Q6). A non-inverting output of the sixth transistor 528 (Q6) may be coupled to the reference voltage 460. The control input of the sixth transistor 528 (Q6) may be configured to receive the charge pump control signal 434 via the resistive divider network formed by the sixteenth resistor 530 (R16) and the seventeenth resistor 532 (R17). The first terminal of the sixteenth resistor 530 (R16) may be configured to receive the charge pump control signal 434. The second terminal of the sixteenth resistor 530 (R16) may be coupled to the control input of the sixth transistor 528 (Q6) and the first terminal of the seventeenth resistor 532 (R17). The second terminal of the seventeenth resistor 532 (R17) may be in communication with the reference voltage 460.

[0068] An anode of a first switching diode 534 (Dl) may be coupled to the supply voltage 404. A cathode of the first switching diode 534 (Dl) may be coupled to a first terminal of the fifth capacitor 506 (C5) and the anode of a second switch diode 536 (D2). The cathode of the second switching diode 536 (D2) may be coupled to a first terminal of a sixth capacitor 540 (C6), which acts as a storage capacitor for the charge pump circuitry 418. A second terminal of the sixth capacitor 540 (C6) may be in communication with the reference voltage 460. The first terminal of the sixth capacitor 540 (C6) may provide the boost supply voltage 436.

[0069] Operationally, in response to the charge pump control signal 434 providing an input voltage substantially equal to the turn-on supply voltage 432, the third transistor 514 (Q3) and the sixth transistor 528 (Q6) are simultaneously turned on. As a result, the fourth transistor 518 (Q4) may turn on to set the voltage at the control input of the fifth transistor 526 (Q5)

substantially equal to the supply voltage 404. As a result, the fifth transistor 526 (Q5) is turned off while the second terminal of the fifth capacitor 506 (C5) is pulled down through the sixth transistor 528 (Q6) to the reference voltage 460. In response, the first switching diode 534 (Dl) may be forward biased to charge the fifth capacitor 506 (C5). The charge stored on the fifth capacitor 506 (C5) may develop a voltage across on the first terminal of the fifth capacitor 506 (C5) substantially equal to the supply voltage 404 less the forward bias voltage of the first switching diode 534 (Dl).

[0070] In response to the charge pump control signal 434 having a voltage level substantially equal to the reference voltage 460, the third transistor 514 (Q3) and the sixth transistor 528 (Q6) simultaneously turn off. As a result, the fourth transistor 518 (Q4) also turns off, which allows fifth transistor 526 (Q5) to turn on. In this case, the fifth transistor 526 (Q5) may pull up the second terminal of the fifth capacitor 506 (C5) to the supply voltage 404, which reverse biases the first switching diode 534 (Dl) and forward biases the second switching diode 536 (D2). The charge stored in the fifth capacitor 506 (C5) may be transferred to the sixth capacitor 540 (C6) through the second switching diode 536 (D2). Accordingly, a boost supply voltage 436 developed across the sixth capacitor 540 (C6) may be substantially equal to twice the supply voltage 404 less the forward biased voltage of the first switching diode 534 (Dl) and the forward biased voltage of the second switching diode 536 (D2).

[0071] In some embodiments, the charge pump circuitry 418 may also include a seventh capacitor 542 (C7) having a first terminal configured to receive the first phase signal 426 and a second terminal coupled to the first terminal of the sixth capacitor 540 (C6). In addition, the charge pump circuitry 418 may further include an eighth capacitor 544 (C8) having a first terminal configured to receive the second phase signal 428 and a second terminal also coupled to the first terminal of the sixth capacitor 540 (C6). During initial startup of the electronic module 400, the seventh capacitor 542 (C7) and the eighth capacitor 544 (C8) may be configured to operate as bootstrap capacitors to speed the charging process of the sixth capacitor 540 (C6).

[0072] FIG. 8 depicts an embodiment of the MOSFET half-bridge control circuitry 420 including a first comparator 546 and a second comparator 548 configured to control a first MOSFET half-bridge circuit 446 as a function of the first phase signal 426. In addition, the MOSFET half-bridge control circuitry 420 may further include a third comparator 550 and a fourth comparator 552 configured to control a second MOSFET half-bridge circuit 448 as a function of the second phase signal 428.

[0073] In some embodiments, the first comparator 546, the second comparator 548, the third comparator 550, and the fourth comparator 552 may be contained in a single integrated chip. For example, the third comparator 550 may include a comparator supply voltage input coupled to the boost supply voltage 436 via an eighteenth resistor 554 (R18). A third zener diode 556 (Z3) may be coupled between the comparator supply voltage input of the third comparator 550 and the reference voltage 460. The eighteenth resistor 554 (R18) and the third zener diode 556 (Z3) may operate cooperatively to protect the first comparator 546, the second comparator 548, the third comparator 550, and the fourth comparator 552 from damage as a result of an over voltage condition created by an overvoltage event, such as a load dump or other event.

[0074] During a load dump event, the supply voltage 404 may spike due to a sudden disconnection of the supply voltage device 402. When the supply voltage device 402 is suddenly disconnect from the electronic module 400, energy stored in the stator 38 may cause the charging voltage 406 to spike because the supply voltage device 402 is not available to receive the energy of the charging voltage 406. An embodiment of the MOSFET half-bridge control circuitry 420 may include load dump protection circuitry 598 suitably configured to disable portions of the MOSFET half-bridge control circuitry 420 in the event of a load dump.

[0075] In some embodiments, the first comparator 546, the second comparator 548, the third comparator 550, and the fourth comparator 552 may be configured as open collector devices. As an example, an output of the first comparator 546 may be coupled to the boost supply voltage 436 via a nineteenth resistor 558 (R19). An output of the third comparator 550 may also be coupled to the boost supply voltage 436 via a twentieth resistor 560 (R20). An output of the second comparator 548 may be coupled to the turn-on supply voltage 432 via a twenty first resistor 562 (R21). An output of the fourth comparator 552 may be coupled to the turn-on supply voltage 432 via a twenty second resistor 564 (R22).

[0076] An inverting input of first comparator 546 may be coupled to supply voltage 404 through a parallel combination of a twenty third resistor 566 (R23) and a ninth capacitor 568 (C9). The first terminal of a twenty- fourth resistor 570 (R24) is configured to receive the first phase signal 426 and the second terminal of the twenty- fourth resistor 570 (R24) is in

communication with a non-inverting input of the first comparator 546. The output of first comparator 546 may be configured to generate a first high gate control signal 572 as a function of the voltage difference between first phase signal 426 and supply voltage 404. A first terminal of a twenty fifth resistor 574 (R25) may include a first terminal configured to receive first phase signal 426 and a second terminal in communication with an inverting input of second comparator 548. A twenty sixth resistor 576 (R26) and a tenth capacitor 578 (CIO) may be coupled in parallel between a non-inverting input of second comparator 548 and reference voltage 460. The output of the second comparator 548 may be configured to generate a first low gate control signal 580 as a function of the voltage difference between first phase signal 426 and reference voltage 460.

[0077] An inverting input of third comparator 550 may be coupled to supply voltage 404 through a parallel combination of a twenty seventh resistor 582 (R27) and an eleventh capacitor 584 (CI 1). A first terminal of a twenty eighth resistor 586 (R28) may include a first terminal configured to receive second phase signal 428 and a second terminal in communication with a non-inverting input of third comparator 550. The output of third comparator 550 may be configured to generate a second high gate control signal 588 as a function of the voltage difference between second phase signal 428 and supply voltage 404. A first terminal of a twenty ninth resistor 590 (R29) may include a first terminal configured to receive second phase signal 428 and a second terminal in communication with an inverting input of fourth comparator 552. A thirtieth resistor 592 (R30) and a twelfth capacitor 594 (C12) may be coupled in parallel between a non-inverting input of fourth comparator 552 and reference voltage 460. The output of fourth comparator 552 may be configured to generate a second low gate control signal 596 as a function of the voltage difference between second phase signal 428 and reference voltage 460. Although not illustrated, a resistor is typically placed in series between each comparator output and the associated MOSFET gate input. In addition, a zener diode (not shown) is typically placed in parallel between the gate and source terminals of each MOSFET for protection against static voltage and ESD.

[0078] An embodiment of the MOSFET half-bridge control circuitry 420 may include load dump protection circuitry 598 configured to disable portions of the MOSFET half-bridge control circuitry 420 in the event of a load dump. During a load dump event, the supply voltage 404 may spike due to a sudden disconnection of the supply voltage device 402. When the supply voltage device 402 is suddenly disconnect from the electronic module 400, energy stored in the stator 38 may cause the charging voltage 406 to spike because the supply voltage device 402 is not available to receive the energy of the charging voltage 406.

[0079] FIG. 8 depicts a non-limiting example of power board 410 including a first MOSFET half-bridge circuit 446 and a second MOSFET half-bridge circuit 448, which is described with continuing reference to FIGS. 4-7. In some embodiments, power board 410 may include a ceramic substrate having low thermal impedance. The power board 410 may be separate from control board 408. For example, control board 408 may include a laminated circuit board.

Although not depicted, control board 408 and power board 410 may be coupled via leads or a connector disposed within electronic module 400. For example, power board 410 may be mounted on a metallic or thermally conductive substrate. The control board 408 may be mounted proximate to power board 410. In some embodiments, control board 408 may be mounted above power board 410. A connector or leads may provide an electrical connection between control board 408 and power board 410. For example, MOSFET control signals 444 from MOSFET half-bridge control circuitry 420 may communicate with MOSFET half-bridge circuitry 422 via conductive connections provided by the connector or lead coupled between control board 408 and power board 410.

[0080] The first MOSFET half-bridge circuit 446 may include a first power MOSFET 642 (Ml) and a second power MOSFET 644 (M2) configured to rectify a first phase signal 426 to generate a charging voltage 406. The charging voltage 406 may charge supply voltage device 402. The first power MOSFET 642 (Ml) may include a drain in communication with the supply voltage terminal 258 (FIG. 6) of the electronic module 400, a source in communication with a drain of second power MOSFET 644 (M2) and configured to also receive first phase signal 426 from stator 38. In some embodiments, first power MOSFET 642 (Ml) may include a gate configured to receive first high gate control signal 572. The second power MOSFET 644 (M2) may include a gate configured to receive first low gate control signal 580. The source of second power MOSFET 644 (M2) may be coupled to reference voltage 460.

[0081] The second MOSFET half-bridge circuit 448 may include a third power MOSFET 656 (M3) and a fourth power MOSFET 658 (M4) configured to rectify second phase signal 428 to generate charging voltage 406. The charging voltage 406 may charge supply voltage device 402. The third power MOSFET 656 (M3) may include a drain in communication with the supply voltage terminal 258 (FIG. 6) of the electronic module 400, a source in communication with a drain of fourth power MOSFET 658 (M4) and configured to also receive second phase signal 428 from stator 38. In some embodiments, third power MOSFET 656 (M3) may include a gate configured to receive second high gate control signal 588. The fourth power MOSFET 658 (M4) may include a gate configured to receive second low gate control signal 596. The source of fourth power MOSFET 658 (M4) may be coupled to reference voltage 460. A fourteenth capacitor 670 (CI 4) may be coupled between the drain of first power MOSFET 642 (Ml) and the reference voltage 460.

[0082] While exemplary embodiments incorporating the principles of the present invention have been disclosed hereinabove, the present invention is not limited to the disclosed

embodiments. Instead, this application is intended to cover any variations, uses, or adaptations of the invention using its general principles. Further, this application is intended to cover such departures from the present disclosure as come within known or customary practice in the art to which this invention pertains and which fall within the limits of the appended claims.

Claims

WHAT IS CLAIMED IS:

1. A system for rectifying an alternating current signal comprising:

MOSFET half-bridge circuitry; and

magnitude detector circuitry configured to:

determine whether the peak magnitude of a phase signal is at least equal to a turn- on threshold level; and

enable the MOSFET half-bridge circuitry to rectify the phase signal in response to the peak magnitude of the phase signal at least equaling the turn-on threshold level.

2. A method for rectifying an alternating current signal comprising:

receiving an alternating current signal from a stator;

determining whether the magnitude of the alternating current signal is at least substantially equal to a turn-on threshold level; and

in response to a determination that the magnitude of the alternating current signal is at least equal to the turn-on threshold level, rectifying the alternating current signal to generate a supply voltage.

3. The method for rectifying the alternating current signal of claim 2, further comprising:

in response to a determination that the magnitude of the alternating current signal is less than the turn-on threshold level, disabling rectification of the alternating current signal to generate a supply voltage.

4. The method for rectifying the alternating current signal of claim 3, wherein determining whether the magnitude of the alternating current signal is at least equal to the turn- on threshold level comprises:

generating a pulse signal as a function of the magnitude of the alternating current signal; integrating the pulse signal to generate a switch control signal; and

providing a turn-on supply voltage and a boost supply voltage to a MOSFET half-bridge control circuitry in response to an assertion of the switch control signal.

5. The method for rectifying the alternating current signal of claim 4, further comprising:

disabling the turn-on supply voltage and the boost supply voltage in response to a de- assertion of the switch control signal.

6. The method of claim 4, wherein in response to the determination that the magnitude of the alternating current signal is at least equal to the turn-on threshold level, rectifying the alternating current signal to generate the supply voltage comprises:

generating a charge pump control signal in response to the determination that the magnitude of the alternating current signal is at least equal to the turn-on threshold level.

7. The method of claim 6, further comprising:

generating a boost supply voltage in response to the charge pump control signal.