Abstract: An apparatus and method for protecting synchronous generators against off-nominal frequency deviation and alternating forces excitation is provided. Particular application can be found with generators within a power generator plant integrated into a power transmission grid system. A electrical relay system is in operative association with an electrical signal representative of an actual frequency at which the generator is operating and to an electrical signal representative of an actual forcing amount at which the generator is operating. The relay system is adapted to respond to the actual frequency signal and the actual forcing signal such that the relay system compares the actual frequency signal with a predetermined desired frequency range and compares the actual forcing signal with at least one predetermined forcing amount, and selectively alarms the unit operator or trips the generator to an off-line mode depending upon the comparisons.

Abstract: A wound field synchronous machine control system comprises: an auxiliary winding for obtaining auxiliary AC voltage from the wound field synchronous machine; a phase controlled rectifier for rectifying the auxiliary AC voltage and supplying rectified DC voltage to the wound field synchronous machine; and a controller. The controller is configured for using a voltage signal across the auxiliary winding to obtain volt-second values of the auxiliary winding and using the volt-second values for firing angle control of switches of the phase controlled rectifier. Alternatively or additionally, the controller is configured for obtaining airgap flux values of the wound field synchronous machine and using the airgap flux values for firing angle control of switches of the phase controlled rectifier.

Abstract: A power factor control apparatus comprises a target power factor setting section which sets a target power factor range of the plurality of power generators in a fixed cycle, a comparing section which compares a voltage of a bus with a predetermined voltage value range, a first control section which performs control, based on a result of the comparing section, to drop a voltage of at least one power generator whose power factor is the lowest, and raise a voltage of at least one power generator whose power factor is the highest, and a second control section which performs control of a voltage of a power generator, whose power factor is out of the target power factor range, such that the power factor thereof falls within the target power factor range.

Abstract: The invention is based on a method for operating an electrical machine (1) for the production of electrical power (13) comprising an excitation winding (2) and a stator winding (4). A converter configuration (6), e.g., a pulse-width modulation inverter, is located downstream from the electrical machine (1). In the lower speed range, the output of electrical power (12) takes place along the torque line (29) independently of the number of coils w1, w2 in a stator winding (4). In the upper speed range, the output of electrical power (12) takes place via a stator winding (4) having a small number of coils w2.

Abstract: A system includes a generator and a circuit. The generator is coupled to provide power to a power grid. The circuit is coupled to the generator and is adapted to use a scheme to detect a shut down of the power grid and prevent the generator from providing power to the power grid in response to the detection of the shut down of the power grid. The circuit is also adapted to receive an indication to modify the scheme and modify the scheme based on the indication.

Abstract: A power adjustment apparatus includes a phase shifter including a stator having a stator winding and a rotor having a rotor winding, a winding terminal of one of the stator winding and the rotor winding being connected to a power-system bus, and a winding terminal of the other being connected to the power-system bus via an impedance load, a driver axially coupled to the rotor to drive the rotor, and a controller which gives the driver a command value to adjust the phase difference between the stator and the rotor to a desired value.

Abstract: A power factor control apparatus comprises a target power factor setting section which sets a target power factor range of the plurality of power generators in a fixed cycle, a comparing section which compares a voltage of a bus with a predetermined voltage value range, a first control section which performs control, based on a result of the comparing section, to drop a voltage of at least one power generator whose power factor is the lowest, and raise a voltage of at least one power generator whose power factor is the highest, and a second control section which performs control of a voltage of a power generator, whose power factor is out of the target power factor range, such that the power factor thereof falls within the target power factor range.

Abstract: A system includes a generator and a circuit. The generator is coupled to provide power to a power grid. The circuit is coupled to the generator and is adapted to use a scheme to detect a shut down of the power grid and prevent the generator from providing power to the power grid in response to the detection of the shut down of the power grid. The circuit is also adapted to receive an indication to modify the scheme and modify the scheme based on the indication.

Abstract: A method of controlling a permanent magnet turbogenerator/motor includes providing a protected load connected in parallel with the turbogenerator/motor through a pulse width modulated inverter configured in a first operating mode to supply controlled current from the turbogenerator/motor to a utility electrical power source, and selectively connected to the utility electrical power source through an isolation device, monitoring the utility electrical power source, and automatically disconnecting the protected load from the utility electrical power source while reconfiguring the pulse width modulated inverter in a second operating mode to supply controlled voltage to the protected load when a fault is detected in the utility electrical power source.

Abstract: An integrated system for comprehensive control of an electric power generation system utilizes state machine control having particularly defined control states and permitted control state transitions. In this way, accurate, dependable and safe control of the electric power generation system is provided. Several of these control states may be utilized in conjunction with a utility outage ride-through technique that compensates for a utility outage by predictably controlling the system to bring the system off-line and to bring the system back on-line when the utility returns. Furthermore, a line synchronization technique synchronizes the generated power with the power on the grid when coming back on-line. The line synchronization technique limits the rate of synchronization to permit undesired transient voltages.

Abstract: An integrated system for comprehensive control of an electric power generation system utilizes state machine control having particularly defined control states and permitted control state transitions. In this way, accurate, dependable and safe control of the electric power generation system is provided. Several of these control states may be utilized in conjunction with a utility outage ride-through technique that compensates for a utility outage by predictably controlling the system to bring the system off-line and to bring the system back on-line when the utility returns. Furthermore, a line synchronization technique synchronizes the generated power with the power on the grid when coming back on-line. The line synchronization technique limits the rate of synchronization to permit undesired transient voltages.

Abstract: A method for optimized power and efficiency regulation of rotary current generators with an associated converter bridge, in particular synchronous machines, is described in which at least three regulation ranges are defined, within which ranges the regulation of the generator takes place by different criteria. The definition of the regulation ranges is done in particular as a function of rpm and as a function of the desired set-point power. The regulation extends both to the exciter current and to the stator current and is done by means of various regulators that exchange information with one another.

Abstract: A genset controller that is configurable for controlling a variety of types of gensets, as well as a method of configuring a genset controller for controlling a genset, are disclosed. The genset controller includes a memory for storing a plurality of software routines, a personality profile data set, and a user-settable data set, and further includes a processor coupled to the memory for executing the software routines and reading data from the personality profile data set and the user settable data set to control the genset. The genset controller additionally includes an input port coupled to the memory for enabling changes to the personality profile data set and the user-settable data set to be downloaded into the memory. The personality profile data set and the user-settable data set include data that configures the genset controller for operation with a particular genset.

Abstract: Process for supplying electrical energy to the network with an AC generator associated with a turbine, by means of a transformer, characterized in that it consists in evaluating the generator precisely as a function of the needs of the site by lowering its nominal voltage as low as possible while continuing to satisfy the capacity of the generator to send active power delivered by the turbine and the reactive power corresponding to this active power required by a consumer or the network manager.

Abstract: A generating system having a rotating type generator to interconnect a power system in order to output power of the generator to the power system comprises a generator, an exciting circuit and an excitation control section. It also comprises short-cycle stabilizing sections for outputting a short-cycle stabilizing signal for suppressing short-cycle power fluctuations according to at least one of an electric parameter and a mechanical parameter of the generator and a long-cycle stabilizing section for outputting a long-cycle stabilizing signal for suppressing long-cycle power fluctuations having a cycle time longer than short-cycle power fluctuations according to the mechanical parameter of the generator. The outputs of the short-cycle stabilizing sections and the long-cycle stabilizing section are sent to the excitation control section.

Abstract: An integrated system for comprehensive control of an electric power generation system utilizes state machine control having particularly defined control states and permitted control state transitions. In this way, accurate, dependable and safe control of the electric power generation system is provided. Several of these control states may be utilized in conjunction with a utility outage ride-through technique that compensates for a utility outage by predictably controlling the system to bring the system off-line and to bring the system back on-line when the utility returns. Furthermore, a line synchronization technique synchronizes the generated power with the power on the grid when coming back on-line. The line synchronization technique limits the rate of synchronization to permit undesired transient voltages.

Abstract: The invention relates to a procedure of connecting a polyphased asynchronous generator on a polyphased alternating voltage network. The connecting is carried out by means of an adjustable, electronic connecting based on thyristors or similar variable (adjustable) connecting items, the connecting degree of which is varied during a controlled connecting course, which is controlled in consideration of the wish of a “soft” connecting on the network and a limitation of the maximum amperage during the connecting course. During the whole connecting course a continuous determination of the generator phase angle &phgr; is carried out, and on basis of this determination a continuous adjustment of thyristors—the aperture angle is carried out, thus the aimed, successive load connection of the generator on the network (soft-connecting) is obtained.

Abstract: An integrated system for comprehensive control of an electric power generation system utilizes state machine control having particularly defined control states and permitted control state transitions. In this way, accurate, dependable and safe control of the electric power generation system is provided. Several of these control states may be utilized in conjunction with a utility outage ride-through technique that compensates for a utility outage by predictably controlling the system to bring the system off-line and to bring the system back on-line when the utility returns. Furthermore, a line synchronization technique synchronizes the generated power with the power on the grid when coming back on-line. The line synchronization technique limits the rate of synchronization to permit undesired transient voltages.

Abstract: A method and apparatus for compensating, consistent with variations in cooling conditions, protection and limit functions of a generator. Limits of the capability curve of the generator, including the overexcited region, underexcited region and region limited by stator current heating, are modified in response to changes in coolant pressure or temperature depending on the type of generator being compensated. Feedback signals and setpoints being provided to fixed protection and limit functions are intercepted and modified in accordance with the relationship between generator rated values and generator performance in view of altered coolant conditions. Protection and limit functions are automatically coordinated. As a result, overall generator performance is improved.

Abstract: A system for controlling reactive currents in a generator is provided. A control system receives current and voltage feedback from the generator. The control system determines a phase angle based on the current and voltage feedback. The control system determines a compensation signal corresponding to the phase angle and current. The control system modifies a generator excitation signal based on the compensation signal and a bi-linear transformation technique.

Abstract: Two generation systems 3, 8 each including inverter 8 are switched over between series connection and parallel connection by switching section 5. Reference waveform signals are mutually communicated between the two generation systems through communication lines 6. When a phase difference between these two reference waveform signals is within a predetermined range, the inverters are driven to generate an output alternating current. One of the conduction angles of thyristors 3a, 3a in two converters 3, 3 which is larger than the other is inputted to a deviation detector 42. Based on a deviation of the conduction angle inputted from a target conduction angle, an updated target rotational speed is set in a calculator 44. A throttle controller 48 controls a throttle opening angle so that an actual rotational speed converges into the target rotational speed.

Abstract: An excitation controller sets an output terminal reference voltage of a synchronous machine from a reactive current output from the synchronous machine and a high side reference voltage of a transformer, and controls the field current supplied to the field winding of the synchronous machine in response to the deviation between the reference voltage and the output terminal voltage. Although a conventional excitation controller can maintain the transmission voltage on the transmission bus at a fixed value, an expensive potential detector is needed for detecting the transmission voltage on the transmission bus, which increases the manufacturing cost of the excitation controller.

Abstract: A method is described for regulating a generator, in particular a three-phase generator which has an excitation coil through which the regulatable excitation current (IE) used to generate the excitation field flows, and has stator coils in which currents are produced that are conveyed to the consumers via pulse inverters. By controlling the pulse inverters, the stator current can be impressed with respect to value and phase in relation to the excitation current so that the output power of the generator is optimized in the required speed range.

Abstract: An alternator system having a single voltage sensor and a half-wave controlled rectifier bridge for increasing/decreasing alternator output power is disclosed. The half-wave controlled rectifier bridge includes three diodes and three active switches. The alternator system further includes a controlled field winding coupled to a three-phase stator winding; a battery; and, a controller for controlling the active switches and the field winding for increasing/decreasing the alternator output power. The controller uses edges sensed by the single voltage sensor for determining optimum activation and deactivation times for the three active switches in the bridge, and then controlling the switches in accordance with the determined optimum switching times.

Abstract: A method and apparatus for compensating, consistent with variations in cooling conditions, protection and limit functions of a generator. Limits of the capability curve of the generator, including the overexcited region, underexcited region and region limited by stator current heating, are modified in response to changes in coolant pressure or temperature depending on the type of generator being compensated. Feedback signals and setpoints being provided to fixed protection and limit functions are intercepted and modified in accordance with the relationship between generator rated values and generator performance in view of altered coolant conditions. Protection and limit functions are automatically coordinated. As a result, overall generator performance is improved.

Abstract: A cross current compensation system for controlling reactive currents in a generator is provided. A control system for receives voltage feedback from a first generator of a plurality of generators and cross current feedback from at least a second generator of the plurality of generators. The control system determines a phase angle based on the voltage feedback from the first generator and cross current feedback from the at least a second generator. The control system determines a compensation signal corresponding to the phase angle and cross current feedback. The control system modifying a generator excitation signal for the first generator based on the respective compensation signal and a bi-linear transformation technique.

Abstract: A method and apparatus for compensating, consistent with variations in cooling conditions, protection and limit functions of a generator. Limits of the capability curve of the generator, including the overexcited region, underexcited region and region limited by stator current heating, are modified in response to changes in coolant pressure or temperature depending on the type of generator being compensated. Feedback signals and setpoints being provided to fixed protection and limit functions are intercepted and modified in accordance with the relationship between generator rated values and generator performance in view of altered coolant conditions. Protection and limit functions are automatically coordinated. As a result, overall generator performance is improved.

Abstract: A rotary induction machine in which operating characteristics of the machine are controlled by adding impedance elements to the rotor windings in which the impedance elements are stationary and connected to the rotor windings by a rotary transformer.

Abstract: An alternator having a sensorless power angle control includes a three phase stator winding and three stator winding outputs connected to a controlled full wave rectifier bridge with a dc output. The controlled full wave rectifier bridge includes upper MOSFET switches and lower MOSFET switches with body diodes. Operation of the alternator results in a three phase back EMF generated in the stator windings and phase voltages across each of the stator windings. The output of the alternator is increased by introducing a phase shift between the back EMF and the phase voltages, resulting in an optimized power angle. In order to provide a reference for the phase of the back EMF, a zero crossing detector is provided which monitors the zero voltage crossings across the body diodes of the lower MOSFET switches. The negative to positive zero voltage crossings across the body diodes of the lower MOSFET devices correspond to the negative to positive zero crossings of the three phase back EMF.

Abstract: A line synchronous generator with an exciter and generator stage. The exciter stage includes an exciter stator and an exciter rotor, and the generator stage includes a generator stator and generator rotor. In one embodiment, the stators are wound with primary windings for connection to an AC power source and the rotors are wound with secondary windings. In an alternative embodiment, the rotors are wound with primary windings for connection to the AC power source and the stators are wound with secondary windings. The proper phase angle alignment of the secondary windings are determined by connecting the primary windings of the exciter and generator stages to the AC power source, and connecting the a secondary winding of the exciter stage to a secondary winding of the generator stage. The remaining open secondary leads are then tested for two pairs having a voltage equal to two times the line voltage, and two pairs having a voltage equal to .sqroot.3 times the line voltage.

Abstract: A generating apparatus for feeding a current to a battery using a magneto as a power supply is disclosed which is capable of varying a magnetic field acting on generating coils to widely control characteristics of the magneto. A rectifying/switch circuit is arranged between the magneto and a load, which incorporates the battery. The rectifying/switch circuit includes diodes and switch elements. The diodes are 2n (n.gtoreq.2) in number and are bridge-connected to each other. The switch elements are connected to the diodes by reverse parallel connection. A switch control unit applies an AC control voltage of a predetermined phase from the battery through the rectifying/switch circuit to the generating coils, so that a phase of the AC control voltage may be varied to widely vary characteristics of the magneto.

Abstract: A regulator for a polyphase alternator for a motor vehicle, the regulator including detector means for detecting a voltage difference between the phase terminals of said alternator, which comprise at least one transistor circuit forming a current mirror whose two branches are connected at one end to respective ones of the two phase terminals and are connected at the other end to transistors forming current sources that supply said branches with currents of the same magnitude, those branches also having resistors of different resistances such that one of the transistors becomes non-conductive when a voltage difference in excess of a given threshold appears between the two phase terminals, said transistor becoming non-conductive giving rise to a change in the level of a logic output controlled by the voltage at a point on said branch between the current source transistor and the current mirror transistor.

Abstract: A regulator for a polyphase alternator for a motor vehicle, the regulator including detector means for detecting a voltage difference between the phase terminals that are to receive the phase voltages from said alternator, and means for detecting a trigger signal for triggering operation in an accelerated mode, wherein the means for detecting a trigger signal comprise means for detecting a particular level of the voltage or current on at least one of the phase terminals, and means for triggering accelerated mode operation when said voltage or current level is detected, and wherein the detector means for detecting a voltage difference between the phase terminals are suitable for detecting said voltage difference at the said current or voltage level on said phase terminal.

Abstract: A rotary induction machine having wound primary and secondary windings with resistive means connected in series with secondary windings and inductive reactive means connected across said resistive means, with the inductive reactance means and resistive means selected to provide an effective resistance which controls the current in the generator secondary windings, whereby the generator rated current is reached at the highest slip for the range of desired power output.

Abstract: A method of linearizing the output performance of a switched reluctance generator, comprises the steps of exciting the switched reluctance generator during a first phase of operation at a turn-on angle which need not be accurately calculated to produce the desired excitation current. Next, during a second phase of commutation, the switched reluctance generator is freewheeled when a phase current of the switched reluctance generator exceeds a first calculated current level. This freewheeling continues until the phase current of the switched reluctance generator exceeds a second calculated current level, at which point the switched reluctance generator enters the generation phase of its commutation cycle. The linearization of the performance occurs because the first and second calculated current levels are calculated as a function of energy converted per electrical cycle.

Abstract: A synchronous condenser has a rotor, a rotor shaft on which the rotor is mounted, and collector rings electrically connected to a source of D.C. voltage. A fluid drive has an output shaft connected to the synchronous condenser rotor shaft through a quick disconnect mechanism, an input shaft, and a motor connected to drive the input shaft. In bringing the synchronous condenser onto line, the speed of rotation of the output shaft of the fluid drive is brought to a speed slightly greater than the synchronous speed, a D.C. voltage is applied to the collector rings of the rotating field to generate a polyphase A.C. voltage in the windings in the stator core, and the polyphase breaker is closed just as the phases are brought into synchronization with the corresponding phases of the power grid. After the synchronization is complete, the disconnect coupling is operated to separate the starting mechanism and the starting mechanism is shut down. The entire process can be accomplished by remote control.

Abstract: A method for detecting islanding operation of a rotating-machine type dispersed generator. The dispersed generator is interconnected with a main electric source through a circuit breaker to constitute an electric power system. The estimating method is implemented as follows: (a) changing electric power of the electric power system; (b) detecting frequency component of the electric power; and (c) deciding that an islanding operation of the dispersed generator is executed if the change of the frequency component becomes greater than a predetermined value. With this method, it becomes possible to detect the islanding operation of the dispersed generator even if the power flow at the interconnecting circuit breaker is generally zero.

Abstract: A variable speed wind turbine generator system to convert mechanical power into electrical power or energy and to recover the electrical power or energy in the form of three phase alternating current and return the power or energy to a utility or other load with single phase sinusoidal waveform at sixty (60) hertz and unity power factor includes an excitation controller for generating three phase commanded current, a generator, and a zero sequence filter. Each commanded current signal includes two components: a positive sequence variable frequency current signal to provide the balanced three phase excitation currents required in the stator windings of the generator to generate the rotating magnetic field needed to recover an optimum level of real power from the generator; and a zero frequency sixty (60) hertz current signal to allow the real power generated by the generator to be supplied to the utility.

Abstract: An apparatus for controlling the output and torque of a synchronous alternator has a controlled bridge rectifier operable off synchronous for rectifying the alternating output and establishing a desired phase relationship between the alternating voltage and alternating current of the output winding. Phase locked loop control may be employed for establishing and maintaining a desired phase relationship to control the output and torque.

Abstract: Duty ratio of a power switching transistor connected to the field coil is controlled according to whether or not a high-power load is connected. When the high power load is not connected, the duty ratio is made 60%, for example, so that excessive power not generated. On the other hand, when the high power load is connected, the duty ratio is increased to 100% so that full power is generated by the generator. The power switching transistor is also controlled according to the battery voltage in a well known manner.

Abstract: In a power generating system having an AC power generator, a quantity which is related to the state of power generation of the power generator and varies according to the supply of a leading phase current to the power generator, is detected. When the passage of the leading phase current through each armature winding is determined as necessary based on the detected status quantity, the leading phase current is supplied to each armature winding (an increase in the amount of supply of the leading phase current is included). If passage is determined as unnecessary, then the supply of the leading phase current to each armature winding is stopped (a decrease in the leading phase current is included). If so, then a change (improvement) in the state of power generation such as an increase in output or the like due to the above supply can be achieved by supplying the leading phase current thereto when its change is required.

Abstract: An exciting current controlling transistor or a high-side switch or low-side switch of a three-phase full-wave rectifier for an on-vehicle a.c. generator is formed of a MOS power transistor made of a monocrystalline SiC semiconductor. Further, at high output condition time, for example, a state wherein the generator is in a condition of low temperature and a battery capacity is decreased, a controller suppresses the duty ratio of the exciting current controlling transistor to thereby limit a field coil exciting current. As a result, an increase in cross-sectional area of the electric wire or a temporary rapid increase in torque of the engine load is avoided. Also, by limiting the rate of increase in the duty ratio, the controller prevents a fall in the engine speed.

Abstract: A variable velocity apparatus includes a wound-rotor induction machine having a primary winding connected to a power system having a power system frequency, a secondary winding excited by an alternating current (AC), a generator-motor shaft, and a load united with the generator-motor shaft. The apparatus includes a frequency detection element for detecting a change in the power system frequency, and a controller for changing a rotational speed of the induction machine based on the detected change in the power system frequency. The change in the rotational speed is made substantially equivalent to the detected change in the power system frequency, so as to maintain a slip frequency of the induction machine essentially constant when the power system frequency changes.

Abstract: In order to restrain increase in rotor temperature and reduction in field magnetic flux in an AC power generator, advanced-phase currents are supplied to stator windings of a stator via semiconductor switching devices by controlling the semiconductor switching devices during the power generating operation of the power generator. By this control, the advanced-phase currents will increase the field magnetic flux and, accordingly, increases in generated voltage. By reducing a field current to a field winding of a rotor by an amount corresponding to the increase in the power generation output, the temperature increase in the field winding can be reduced.

Abstract: Leading current or lagging current of an alternator is supplied by a simple structure including short-circuit switch elements. The short-circuit switch elements are connected across output terminals of the alternator three-phase armature windings, and are turned on and off at fixed timings to supply a suitable amount of the leading current to armature windings regardless of the rotational speed. Thus, the leading current can be supplied without phase-leading-capacitors so that the apparatus can be made compact, lightweight and powerful. Even if any of the short-circuit switch elements can not turn off, the battery discharge can be prevented.

Abstract: A power-generating voltage outputted from a vehicle synchronous power generator is adjusted to a first voltage for charging a battery under the control of a field current. Further, a leading phase current that leads a phase voltage is supplied to each of multiple armature windings and the field current is supplied to the field winding, whereby the power-generating voltage can be adjusted to a second voltage higher than the first power-generating voltage. Owing to the above construction, a voltage higher than the normal voltage can be generated by supplying each leading phase current from the vehicle synchronous power generator; hence power can be supplied to a high-voltage load based on the generated high voltage.

Abstract: A system information input means takes in system information and a system state determining means determines states of the system. A component operation state determination means determines operation states of system stabilizing components. A control plan deciding means decides a control plan of the system in consideration of operation states of the system and the system stabilizing components. In deciding the control plan, a swing mode analyzing means firstly analyzes the swing mode at each place of the system on the basis of waveforms of time domain response simulations. Then, a control allotment setting means determines control allotment for each of the system stabilizing components based on the mode analysis and a control parameter setting means control sets the control parameters of each of the system stabilizing components. If plural control plans are obtained, the optimal one is selected based on eigenvalues of dynamics of the system or by evaluating time domain system responses by simulation method.

Abstract: On a stator core, there are wound T-connection primary generating windings such that the second and third single-phase windings are respectively arranged at positions electrically orthogonal to the first single-phase winding. The winding number of the first single-phase winding is 31/2 times that of the second single-phase winding or the third single-phase winding. The stator excitation windings are also wound on the stator core, which are connected to the center taps of the primary generating windings through a control rectifier. A plurality of field windings are wound on a rotor core. The field windings are arranged at positions where they are magnetically coupled with both the odd-order spatial higher harmonic components of armature reaction magnetic fields produced by currents flowing in the primary generating windings and the static magnetic fields produced by current flowing in the stator excitation windings.

Abstract: A system for determining rotor position of an n-phase alternator driven by an inverter uses as inputs the stator terminal voltages of the alternator with respect to the negative power bus, which are already also provided as inputs to the inverter, and provides as outputs simulated rotor positions states. The simulated rotor position states are provided to one or more inverter controllers which, in turn, provide firing signals to one or more corresponding inverters which are used to crank an engine, e.g., an internal combustion engine of a diesel electric locomotive.

Abstract: A digital voltage regulator for an electrical power system including a permanent magnet generator (PMG), an exciter, and a main generator. A controller multiplies the frequency of the generator output voltage by a predetermined value to provide a sampling signal having the multiplied frequency and synchronized with the generator output voltage. The controller also provides a sawtooth voltage signal having a repetition rate equal to the frequency of the sampling signal and an incrementing rate determined by the system clock signal. The generator output voltage is sampled at the frequency of the sampling signal. When the difference between the sampled signal and a reference voltage is greater than the sawtooth voltage, the PMG voltage is switched to provide voltage for the exciter field winding.