Abstract: A fan device with improved speed control module includes a stator, a rotor, and a speed control module. The stator has a driving unit outputting currents for the stator to generate alternative magnetic fields and thus turn the rotor. The speed control module includes a control unit and a speed adjusting circuit, with the control unit generating a control command for the driving unit and further outputting a state signal for the speed adjusting circuit to control whether a PWM signal enters the control circuit or not.

Abstract: A drive circuit comprising: a direct current power source; a control unit for supplying control signals; a power switch topology comprising a first switch and a second switch each having an input terminal, an output terminal, and a control terminal, the input terminals being respectively connected to the power source, the control terminals being connected to the control unit for receiving the control signals there from, the output terminals being connected to a node; and an inductance connected with a capacitive load in series between the node and the power source, wherein the control signals control the switches to alternately conduct to thereby cause the node to output a pulse signal.

Abstract: A control method of the electromotor comprises: setting a target alternating axis current based on the rotor angular velocity of the electromotor and a target direct axis current based on the torque of the motor; simultaneously detecting three-phase currents and current rotor position angle of the electromotor; converting the three-phase currents to an actual alternating axis current and an actual direct axis current by Park and Clark conversions; inputting the difference between the target current and the actual current to a current loop, outputting the required direct axis current and the required alternating axis current; determining the three phase voltages according to the required direct axis current and alternating axis current and the angle of the electromotor rotor position; obtaining PWM control waveform through three-phase voltages, wherein said PWM control waveform is configured to control the conversion from direct current to alternating current and drives the electromotor.

Abstract: A system for compensating the characteristics of a fan, applied to a heat-dissipating fan of an electronic device. This system comprises of an analyzing module for analyzing the relation between the duty ratio of pulse width modulation (PWM) and the rotational speed of the fan to generate analyzing data, and a compensating module for generating compensating data basing on the analyzing data and a specific proportion relation between the temperature and the duty ratio of PWM.

Abstract: To estimate a fluctuation component of the torque generated at the motor accurately, a motor control device (3) which controls a motor with a stator having armature winding and a rotor having a permanent magnet is provided to include a torque fluctuation component estimation unit for estimating a torque fluctuation component generated at the motor based on flux-linkage of the armature winding and an armature current that flows the armature winding. The torque fluctuation component estimation unit estimates the torque fluctuation component (Trp) based on an inner product (Fd·id+Fq·iq) of a flux-linkage vector which is a vectorial representation of the flux-linkage and a current vector which is a vectorial representation of the armature current.

Abstract: A dead-time compensation method is applied to a PWM inverter, which is provided to drive an induction motor using a constant V/f control. The method first calculates a root-mean-square current of the output instantaneous current of the inverter. Afterward, a lookup table of the root-mean-square current is used to obtain a dead-time compensation base voltage and a dead-time compensation per-unit voltage. Finally, the dead-time compensation base voltage is multiplied by the dead-time compensation per-unit voltage to produce a dead-time compensation voltage of the PWM inverter. Accordingly, the method reduces complexity of converting the current to the voltage to reach a faster real-time response. Furthermore, a more accurate dead-time compensation voltage is obtained without increasing hardware costs and the efficiency of operating the induction motor is improved at low speed and light load condition.

Abstract: The invention relates to electric engineering, in particular to methods for controlling an ac electronic motor. The inventive control method consists in starting and rotating a rotor upon EMF signals in current-free sections of an armature winding, in converting the EMF signals into discrete logical level signals by a normalizer, in detecting switching points by means of a microcontroller and in displacing said points according to a load current quantity, the rotor speed of rotation and the inductance of the armature winding sections, wherein the switching points are calculated and displaced with respect to bridging times of the free sections EMF whose voltage levels are different from zero. The inventive device is characterized in that it comprises a reference level displacing unit (26), which is arranged in the normalizer between a divider 22 and a comparator unit (23) and which consists of a current sensor (27), a voltage sensor (27), two adders (29, 30) and an inverter (31).

Abstract: A device for filtering a carrier frequency of a PWM waveform. The device includes a low-pass filter for converting the PWM waveform into an analog signal. The device further includes a sampling analog-to-digital converter receiving the analog signal from the low-pass filter and the device also includes a controller for causing the non-integrating analog to digital converter to sample the PWM waveform at the pulse frequency rate thereby rejecting the carrier frequency. As already stated the PWM waveform includes a pulse which has a leading edge, a top portion, and a trailing edge. In one embodiment, the controller causes the A/D converter to sample during the top of the pulse. Preferably, the controller causes the A/D converter to sample at substantially the center of the pulse.

Abstract: A motor control device includes a dq-axis current control unit for generating a dq-axis voltage reference based on a dq-axis current reference and a dq-axis current signal, an initial magnetic pole position estimation unit for estimating a magnetic pole position of the motor upon power-on to generate a magnetic pole position signal, and a magnetic pole position estimation precision confirming unit for supplying a current in a d-axis direction after generation of the magnetic pole position signal with the initial magnetic pole position estimation unit, and checking an error of the magnetic pole position signal based on an angle of movement of the motor.

Abstract: A controller is capable of executing direct couple control that directly couples a first power device and a second power device without causing a DC/DC converter to convert voltage. During the direct couple control, a drive signal that causes no voltage conversion is intermittently output to at least one of a plurality of switching devices.

Abstract: An overmodulation PWM controller includes a voltage instruction calculation unit which calculates a d axis voltage instruction and a q axis voltage instruction in which a voltage amplitude exceeds a peak value of a triangular wave carrier; a voltage instruction correction unit which corrects the d axis voltage instruction and the q axis voltage instruction so that a pulse width modulation voltage applied to an AC motor has a fundamental wave amplitude corresponding to the voltage instruction amplitude, according to the synchronization value K which is the number of the triangular carriers per one cycle of the phase voltage instruction; and a voltage instruction conversion unit which converts the corrected d axis voltage instruction and the q axis voltage instruction into a phase voltage instruction. The pulse width modulation voltage is controlled according to the result of comparison between the phase voltage instruction and the triangular wave carrier.

Abstract: A method and computer program product for defining a PWM drive signal having a defined voltage potential. The PWM drive signal has a plurality of “on” portions and a plurality of “off” portions that define a first duty cycle for regulating, at least in part, a flow rate of a pump assembly. At least a portion of the “on” portions of the PWM drive signal are pulse width modulated to define a second duty cycle for the at least a portion of the “on” portions of the PWM drive signal. The second duty cycle regulates, at least in part, the percentage of the defined voltage potential applied to the pump assembly.

Abstract: A controller for an induction motor includes a storage device which stores values in a plurality of addresses, a first counter which transits circularly among first to N-th states, a second counter which transits circularly among first to fourth states, a calculating section which calculates calculation values, and a signal generation section which generates PWM signals and synchronous interruption signals at constant time pitch such that pulse widths of the PWM signals are adjusted based on the calculation values respectively. An inverter supplies electric power to an induction motor based on the PWM signals. The first counter transits from one to next of the first to N-th states synchronously to each of the synchronous interruption signals. The second counter transits from one to next of the first to fourth states synchronously to each transition of the first counter from the N-th state to the first state.

Abstract: An integrated circuit for controlling a DC motor is disclosed. The integrated circuit includes at least one digital position and speed circuit (DPS) for providing measurements of speed, position, and direction of the motor, the DPS being in signal communication with the motor for receiving a pair of signals having a quadrature relationship; and at least one programmable gain amplifier (PGA) electrically coupled to the motor, the PGA being configured to receive a feedback signal indicative of current flowing through the motor and to apply a second signal to the motor for adjusting the speed of the motor; and at least two analog-to-digital converters (A/D), one A/D being used to quantize the output of the PGA for an off-chip processor; and another A/D to provide motor reference position from an analog sensor, such as a potentiometer; and at least two digital-to-analog converters (D/A), one D/A used to set the motor voltage; and another D/A used to set the motor current limit.

Abstract: The semiconductor device according to the present invention generates pulse width modulation signals for controlling inverter circuits that drive a motor. The semiconductor device includes: a first register which holds values for determining a period in which each pulse width modulation signal becomes active; a correction buffer which holds a correction value; a first counter; a second counter which counts a value obtained by temporally advancing or delaying a count value of the first counter; a selector which selects the count value of the first counter or the count value of the second counter; and a pulse width modulation control unit which generates each pulse width modulation signal, logical values of which are switched in a timing when the selected count value matches the value held by the first register.

Abstract: Method and system are provided for controlling an alternating current (AC) motor via an inverter. The method includes selecting a pulse sequencing method based on a modulation index of the inverter, and providing a voltage to the AC motor based on the pulse sequencing method. The system includes an inverter having a modulation index (Mi) and a controller coupled to the inverter. The controller selects a pulse sequencing method based on Mi and produces a signal based on the pulse sequencing method. The inverter includes a switch network producing a voltage in response to the signal, and the voltage drives the AC motor.

Abstract: A frequency converter for outputting a power to drive a motor, having: an inverter unit for inverting a d.c. power to an a.c. power; a control unit for controlling the inverter unit; and a housing for supporting at least the inverter unit and control unit, wherein a rise time change unit is provided in the housing, the rise time change unit changes a rise time of a waveform of a voltage output from the inverter unit.

Abstract: Power electronics equipment includes air-cored insulating transformers inserted between a control circuit grounded to a vehicle body and an upper arm biased at a high voltage, and air-cored insulating transformers between the control circuit grounded to the vehicle body and the lower arm biased at a high voltage. Each of the air-cored insulating transformers includes a primary winding and a secondary facing to each other. The power electronics equipment facilitates improving resistance against hazardous environments, suppressing the deterioration by aging, reducing the adverse effects of noise caused by external magnetic flux, and transmitting and receiving signals while insulating the low and high voltage sides electrically from each other.

Abstract: A controller for a motor is capable of reducing the amount of energization required to operate a motor under a predetermined condition, the motor having two rotors disposed around a rotating shaft.

Abstract: A controller for a motor permits efficient energization control according to an operating condition of a motor without depending on a number of revolutions of the motor when operating a motor having two rotors disposed around a rotating shaft. The controller includes a voltage-between-terminals increaser which carries out at least one of first processing for increasing a voltage between terminals in which a rotor phase difference is changed by an actuator in a direction for reducing the magnetic fluxes of fields of the motor, second processing for increasing a voltage between terminals in which an output voltage of a DC power source is increased by a DC/DC converter, and third processing for increasing a voltage between terminals in which d-axis current is increased in the case where the magnitude of a resultant vector of a command value of a d-axis voltage and a command value of a q-axis voltage in the motor exceeds the radius of a target voltage circle.

Abstract: A method for controlling an alternating current (AC) motor includes choosing a pulse sequence based on a ripple current in the AC motor at a sampling instant; and providing a voltage to the AC motor based on the pulse sequence.

Abstract: A coordination control device of a power output apparatus includes a coordination control unit. The coordination control unit calculates an intermediate value between the maximum value and minimum value among voltage controls for a first motor generator, and voltage control from an AC voltage control generation unit to generate an AC voltage across neutral points of first and second motor generators, and outputs a value that is each phase voltage control for the first and second motor generators minus the calculated intermediate value to a signal generation unit as the final voltage control for the first and second motor generators.

Abstract: A motor control device is used to control a motor to rotate. The motor control device includes a phase-wave signal sampling module, a first waveform modulating module, a second waveform modulating module and a control signal integrating module. The phase-wave signal sampling module outputs a first phase-wave signal and a second phase-wave signal in accordance with the rotation of the motor. The first waveform modulating module generates a first control signal in accordance with the first phase-wave signal. The second waveform modulating module generates a second control signal in accordance with the second phase-wave signal. The control signal integrating module generates a rotation rate control signal in accordance with the first control signal and the second control signal, and inputs the rotation rate control signal to a drive module to control a rotation rate of the motor.

Abstract: A method for controlling an alternating current (AC) motor includes choosing a pulse sequence based on a ripple current in the AC motor at a sampling instant; and providing a voltage to the AC motor based on the pulse sequence.

Abstract: A drive system for a three phase brushless AC motor that is operative to optimize a transistor switching pattern to improve power output while allowing current measurement in all of the phases using a single sensor. This is achieved by defining a voltage demand vector where more than two states are required to meet a minimum state time requirement determined by the single sensor and calculating three or more state vectors that produce the demand vector while still allowing single current sensing.

Abstract: A motor control apparatus capable of expanding a voltage output and a modulating wave signal generating method for a PWM inverter apparatus of the motor control apparatus, which is controlled by a pulse width modulating signal obtained by comparing a modulating wave signal of a voltage instruction with a carrier wave are provided. An upper limit value calculation unit 105 and a modulation wave limiter unit 4 are provided, and an upper limit value 14 of a modulating wave, which is equal to or smaller than the maximum value of the carrier wave and equal to or larger than the minimum value of the carrier wave is produced in the upper limit value calculation unit 105 and modulating wave instructions 13 for a plurality of phases are corrected by the modulating wave control unit 4 by using the upper limit value 14 of the modulating wave.

Abstract: An alternating current, multiphase, squirrel cage induction electric motor in a unique inverted design, including a method of applying the motor with controls, operator interface, batteries, and peripheral devices to propel a non-polluting electric vehicle.

Abstract: In a method of generating pulse-width modulated waveform, the cycle of a carrier wave for the waveform is determined together with a first dead time value and a second dead time value both of which are set in a plurality of up-down counters, respectively. Using the plurality of the up-down counters is effective to assign individual dead times to upper and lower arms and to linearly control a PWM duty from 0% to 100%.

Abstract: Method arid apparatus for accelerating a multi-phase motor having a rotatable rotor are disclosed. The method incorporates use of a motor control circuit to predict a subsequent loss of frequency lock between the motor control circuit and a motor while the motor control circuit and the motor remain frequency locked, and based on the prediction, steps to avert a loss of frequency lock during acceleration.

Abstract: A multi phase motor includes a switching array for interconnecting a power source to each phase. A current sensor senses current supplied from the power source via the switching array to the winding and a controller generates offset PWM signals for controlling the switching array to supply power to each of the phases of the winding. The offset timing allows the individual phase currents to be determined from a single current sensor.

Abstract: A lead-angle control device according to the present invention includes: a space voltage vector controller calculating effective vector application times necessary for obtaining output voltage vectors of an inverter from stationary-coordinate-system instruction voltage components; a lead-angle compensator comparing the sum of the effective vector application times with a sampling period, and generating lead-angle compensation values; a speed controller generating an instruction current for compensating an error caused by a difference between an instruction speed and a current speed; an instruction current generator which generates a rotating-coordinate-system instruction current component by extracting a lead-angle component at a point where maximum torque-per-ampere can be obtained from the magnitude of the instruction current and performing a mathematical calculation on the magnitude of the instruction current and a lead-angle component; and an instruction voltage generator generating a stationary-coordinat

Abstract: A controller for a variable frequency drive monitors electrical power from a variable frequency drive motor while a brake is maintaining a load driven or moved by the motor without requiring additional feedback components of a closed loop configuration. If excess electrical power is being generated by the motor, an undesirable condition in the brake is indicated. Support or maintenance of the load is assumed by the motor in that event. Appropriate alarms or indicators are also activated.

Abstract: An apparatus corrects a current value of a three-phase electric motor including a current detector that detects current of each of three phases including a first phase, a second phase, and a third phase. The apparatus includes a current-value correcting unit. When current of one of the first to third phase is zero-crossing, the current-value correcting unit corrects a current value of at least one of the others of the first to third phases on a basis of a correlation between detection values of the current detectors provided for the others of the first to third phases during a period in which the three-phase electric motor is operating.

Abstract: A frequency converter for outputting a power to drive a motor, having: an inverter unit for inverting a d.c. power to an a.c. power; a control unit for controlling the inverter unit; and a housing for supporting at least the inverter unit and control unit, wherein a rise time change unit is provided in the housing, the rise time change unit changes a rise time of a waveform of a voltage output from the inverter unit.

Abstract: A method of controlling of an induction machine using an inverter is disclosed with output LC filter. The method includes determining an inverter output current vector (iA), determining an inverter output voltage vector (uA), and forming a full-order observer having a system matrix (Â) and gain vector (K). The observer produces an estimated rotor flux linkage vector ({circumflex over (?)}R), an estimated stator current vector (îs), an estimated stator voltage vector (ûs) and an estimated inverter output current vector (îA). An estimation error (iA?îA) of the inverter output current vector is determined, and a speed adaptation law is formed based on the estimation error of the inverter output current vector for determining an estimate for electrical angular speed ({circumflex over (?)}m) of the induction machine. The induction machine is controlled based on the produced estimates and a measured inverter output current.

Abstract: A motor drive system without any portion for directly detecting the rotor position, rotation speed and motor phase currents, capable of realizing a high-performance variable speed drive even at high carrier frequencies. When detecting a current from a DC power supply of an inverter for driving a motor, applied voltages and frequencies to the motor are controlled based on sampled values by sampling a current flowing as intermittent pulses in the vicinity of each power conduction time period.

Abstract: A speed control apparatus having a high frequency generator for superposing a high frequency signal on an estimated magnetic flux axis. A high frequency component extractor extracts an error signal of a magnetic flux position from a voltage or current detection signal having the same frequency component as a frequency component of the high frequency signal. A magnetic flux observer estimates a magnitude and a position of a magnetic flux. A first adaptive regulator adaptively regulates an error signal on a high frequency superposing side. A second adaptive regulator adaptively regulates an error signal on a magnetic flux observer side. A hybrid device switches the first adaptive regulator at a very low speed, the first and second adaptive regulators at a low speed and the second adaptive regulator at a high speed. A speed estimator estimates a speed from an output of the hybrid device.

Abstract: A controller for a wound-rotor induction motor includes a first voltage-type converter connected to a secondary winding of the motor, a capacitor for smoothing DC output thereof, a second voltage-type converter to supply an AC power supply with regenerated secondary power, a speed detector of the motor, a secondary current detector of the motor, a DC voltage detector applied to the capacitor, a speed controller for controlling the speed by the speed detector and outputting a secondary referential current, a first PWM controller to control the secondary current in response to the referential current, and to output a voltage signal by witch switching elements of the first voltage-type converter are controlled by PWM, and a second PWM controller to control a voltage output from the voltage detector in response to a referential voltage, and to control by PWM switching elements of the second voltage-type converter.

Abstract: A three-phase spindle motor has three terminals each driven with pulse width modulated signals. Rotation of the motor is controlled by iteratively measuring an electrical period of the motor, determining a rotational position of the motor, and synchronizing the sinusoidal pulse width modulation of the spindle motor with the measured electrical period. The electrical period of the motor is measured by detecting zero crossings in the a back electromotive force induced at a first terminal of the motor and determining the time between successive zero crossings. The rotation position of the motor is determined based upon the last measured electrical period and a location of last detected zero crossing. The zero crossings are detected by selecting a time window during which the back electromotive force signal is sensed for zero crossings. The time window is selected as a function of the last measured electrical period and the rotational position of the motor.

Abstract: Methods and apparatus for controlling switching in a DC-to-AC inverter to prevent overvoltages applied to an AC motor by determining the switching order of the phase voltage signals, providing gating signals at switching intervals by modulating a carrier wave with the phase voltage signals, comparing the switching intervals to a predetermined minimum time interval sufficient for reflected wave transients to dissipate, and adjusting the switching intervals to be at least equal to the predetermined minimum time interval.

Abstract: A system for controlling a motor comprising: a voltage source; a motor in operable communication with an inverter, the motor responsive to a command signal from the inverter, the inverter is in operable communication with the voltage source and a controller. The inverter includes a plurality of switching devices configured to receive a command from a controller and generate a voltage command to the motor. The system also includes a voltage sensor for detecting a voltage of the voltage command to the motor at a selected instance; and a controller in operable communication with the inverter and the voltage sensor. The controller configured to provide a command to the inverter responsive to the voltage of the voltage command to the motor at a selected instance.

Abstract: A control system for an electric machine includes a flux weakening module, which includes a voltage magnitude calculator that receives d-axis and q-axis command voltages and that generates a voltage magnitude. An error circuit compares the voltage magnitude to a reference voltage and generates an error signal. A controller receives the error signal and generates a feedback flux correction signal. A limiter limits the feedback flux correction signal to a predetermined flux value and generates a limited feedback flux correction signal. A feedforward stator flux generating circuit generates a feedforward stator flux signal. A summing circuit sums the feedforward stator flux signal and the limited feedback flux correction signal to generate a final stator flux command.

Abstract: An apparatus for driving a brushless motor and method of controlling the motor, which actively changes an output time of a phase commutation signal depending on variation of a load and stably operating the motor in an overloaded state and improving an operational efficiency of a system. The apparatus for driving a brushless motor includes an inverter, a driver, a counter-electromotive voltage detector and a controller. The inverter switches driving voltages applied to multi-phase stator coils. The driver drives the inverter. The counter-electromotive voltage detector detects a counter-electromotive voltage induced from an unexcited stator coil. The controller calculates a time required to detect a counter-electromotive voltage through the counter-electromotive voltage detector after the driving voltage is turned off, determines a phase commutation point of time based on the determined elapsed time, and controls the driver to perform phase commutation at the determined phase commutation time.

Abstract: An electric motor control apparatus of this invention estimates changes in temperature of a semiconductor device to compute temperature change amplitude 108 based on an output current signal 105 computed from a current flowing through the semiconductor device of a switching circuit 5, an operating frequency signal and a carrier frequency signal by a temperature change estimation part 11, and makes conversion into the number of power cycles 110 corresponding to the temperature change amplitude 108 from power cycle curve data stored in a power cycle curve data storage part 14 and computes a thermal stress signal 111 by a thermal stress computation part 13, and does life estimation of the semiconductor device based on the thermal stress signal 111 and produces an output to a display part 16 as a life estimation result signal 112 by a life estimation part 15a.

Abstract: The motor driver having a plurality of output circuits each having two switching elements connected in series includes: a phase switch circuit for putting a switching element on one side of one output circuit among the plurality of output circuits in the ON state during a time period corresponding to a predetermined electrical angle, and performing switching operation for switching elements on the other side of plural output circuits among the remaining output circuits; and a conduction period control section. The conduction period control section generates a signal for controlling the switching operation. Specifically, when the number of times of switching operation performed during the time period corresponding to the predetermined electrical angle is equal to or less than a predetermined value, a switching element corresponding to a phase, for which the magnitude of the current should be decreased, is turned OFF in the time period corresponding to the next predetermined electrical angle.

Abstract: A motor control system for use in heating, ventilation and air conditioning applications including a blower and a motor coupled to drive the blower, an inverter coupled to provide energization to the motor, a relay capable of coupling the motor to the output of the inverter or to line power, and a controller providing signals to control the output of the inverter, where, upon startup and transfer of the motor from the line to the inverter, the output of the inverter is controlled by the inverter to provide for an enhanced startup or transfer.

Abstract: An independent back memory module is disclosed that is permanently installed at a security gate installation. The memory module has a nonvolatile memory and it is positioned within the system so that it automatically has a communication link with any gate controller installed. The memory module records a history of the operation of the system. The memory module retains operational information regarding the system and information identifying the gate controller, gate controller board and the setup of the particular installation. The memory module also retains information regarding changes made in the setup of the system. Whenever a new gate controller board is installed information in the memory module is transmitted to the new controller board.

Abstract: A method for implementing active deadtime control of an inverter associated with an electric motor is disclosed. In an exemplary embodiment, the method includes receiving a command voltage signal indicative of a desired load to be driven by the motor. Based upon the value of the command voltage signal, a determined value of deadtime is applied to switching circuitry in the inverter, wherein the value of deadtime relates to an amount of time in which the switching of a device in the switching circuitry is delayed so as to prevent a short circuit condition within the inverter.

Abstract: Embodiments of present invention may provide a motor control drive circuit for driving a motor by receiving signals from a digital signal control device. The motor control drive circuit includes a switching unit receiving signals that have undergone pulse width modulation (PWM signals) in the digital signal control device, and converting a switching state based on the input signals; and a controller receiving from the switching unit switching operational signals that vary according to a duty ratio of the PWM signals, receiving digital signals from the digital signal control device, and varying a voltage gain for control of the drive motor. In the motor control drive circuit of one embodiment of the present invention, motor rotation is controlled by the duty ratio of digital signals without the use of a DAC. This allows for the design of an independent digital signal processing device, and enables compatibility with various digital signal processing devices.

Abstract: A method and apparatus to be used with a motor controller generating firing pulses to control an inverter, the inverter providing exciting voltage to a motor corresponding to the firing pulses, the voltage having a maximum intended amplitude, the method for substantially eliminating exciting voltage overvoltage by modifying the firing pulses, the method comprising the steps of identifying characteristics of an initial firing pulse, comparing the initial pulse characteristics to an overvoltage characteristic set known to cause overvoltage, where the initial pulse characteristics match the overvoltage characteristic set, altering the initial firing pulse such that the altered firing pulse does not cause overvoltage, identifying an accumulated error corresponding to the altered firing pulse, modifying the firing pulse following the altered firing pulse as a function of the accumulated error to generate a composite firing pulse; and repeating the identifying, comparing, altering, identifying and modifying process