Abstract: A power conversion circuit having a solid-state circuit breaker integrated therein is disclosed. With a disconnect switch between a utility source and the power conversion apparatus described for meeting UL489, the power conversion circuit includes an input connectable to an AC source, a rectifier circuit connected to the input to convert an AC power input to a DC power, and a DC link coupled to the rectifier circuit to receive the DC power therefrom. The rectifier circuit comprises a plurality of phase legs each including thereon an upper switching unit and a lower switching unit, wherein at least one of the upper and lower switching units on each phase leg comprises a bi-directional switching unit that selectively controls current and withstands voltage in both directions, so as to provide a circuit breaking capability that selectively interrupts current flow through the rectifier circuit, while maintaining original power conversion functionalities.

Abstract: The present disclosure includes a system, method, and device related to data collection and communication related to after-market and external vehicle systems, such as towing systems, cargo carrying systems, trailer breakaway systems, brake systems, braking control systems, and the like. Data is sensed, processed, shared, and further leveraged throughout the discrete components of the system, and possibly via internet and other communications' links, to effect various beneficial actions with minimal driver/user interaction or intervention. In the same manner, data from the system may be used for diagnostic reasons, safety controls, and other purposes.

Abstract: A motor drive controller is provided that includes a current source inverter. The current source inverter includes driver circuitry configured to generate switching commands; a variable current source configured to generate a variable current that regulates power in a motor; and motor commutation circuitry configured to receive the variable current and switching commands, and to commutate phase currents that are output to the motor.

Abstract: An electric vehicle includes a main battery, a power converter, a relay, and a controller. The power converter is a device that converts power of the main battery to drive electric power for a motor. The power converter includes a voltage sensor that measures an input voltage. The relay is connected between the main battery and the power converter. The controller stores an output value of the voltage sensor as an offset value at time after a vehicle main switch is turned on and before the relay is closed. The controller controls the power converter based on a value acquired by subtracting the offset value from the output value of the voltage sensor after the relay is closed. The controller opens the relay when a value acquired by subtracting the offset value from the travel-time output value exceeds a first voltage threshold.

Abstract: The present disclosure relates to an apparatus and a method for controlling an electric power steering motor, and the apparatus may include: a transceiver configured to receive information on a steering angle and information on an electric power steering motor and to transmit a control signal to the electric power steering motor; a motor operation determiner configured to recognize a rack stroke range and to determine whether a motor-limitation mode must be initiated or terminated based on the received information on the steering angle and electric power steering motor; and a motor control signal generator configured to generate a control signal corresponding to the determined initiation or termination of the motor-limitation mode.

Abstract: A vehicle charging apparatus includes: an AC/DC converter configured to variably output a DC link voltage; and a DC/DC converter electrically connected to the AC/DC converter and configured to acquire an output voltage by conversion of the DC link voltage outputted by the AC/DC converter and transmit the acquired output voltage to a battery. The AC/DC converter includes: a first switch element configured to adjust a power factor of the AC/DC converter according to an operation of the first switch element, and a second switch element configured to increase the DC link voltage outputted by the AC/DC converter according to the operation of the first switch element.

Abstract: When a rotor performs an ordinary rotation operation, an axial position of the rotor is retained such that the rotor is rotatable with respect to a stator. When a parking brake switch is operated while a vehicle is at stoppage, a rotor slider slides the rotor in an axial direction against a preload of an axially preloading part. This brings an engaging portion of the rotor into engagement with an engaged portion of a housing. The reverse input holder retains the rotation angle of the rotor during the engagement due to the fact that the engagement between the engaging portion and the engaged portion is maintained against a reverse input load acting on the rotor as an external force that accompanies a reaction force of a pressing force of a brake friction member.

Abstract: A motor assembly includes a three-phase asynchronous machine equipped with three stator phases, a capacitor assembly to establish self-excited generator operation of the asynchronous machine, a load resistor assembly to establish resistive load for self-excited generator operation of the asynchronous machine, and a load resistor switch which is arranged to connect the load resistor assembly to the stator phases. The load resistor assembly is asymmetrical.

Abstract: A motor driving device controls driving of an inverter device, detects current values in two phases, and compensates a value. The motor driving device detects current values in two phases, namely, a maximum phase current value and a minimum phase current value, within a single cycle of a PWM carrier frequency. The motor driving device compensates a value obtained by subtracting an absolute value of a difference between two absolute values, namely, the detected maximum phase current value and minimum phase current value, from the smaller value of the absolute values, as the offset current component.

Abstract: Disclosed are half bridge inverter unit and inverter thereof. The half bridge inverter unit includes an inverter controlling module and inductors. The inverter controlling module provides different connection modes based on different operation modes so that the inverter meets the requirement of wide input voltage range as it can work in either voltage step-up mode or voltage step-down mode. The mid-point voltage between the DC series capacitors connected in parallel with DC power supply can be balanced automatically by taking advantage of the grid voltage symmetry with regard to positive and negative half cycles. The inverter is of single stage structure. It has advantages of low power loss, low cost, high efficiency and reliability.

Abstract: A method for operating an electric machine having a power inverter, which is electrically connected to a relative ground potential, and a ground differential voltage between the relative ground potential and a reference ground potential is monitored, and if the ground differential voltage reaches an upper limit value, the electric machine is operated in a current-delivering operating state, and if the ground differential voltage reaches a lower limit value, the electric machine is operated in a non-current-delivering operating state.

Abstract: A driver circuit for a three phase direct current (DC) brushless motor include: three bridge arms each having a first switch, a second switch, and a first diode and a second diode respectively and electrically coupled with the first switch and the second switch in parallel, and three capacitor arms each having a first capacitor and a second capacitor to electrically couple a center tap of a corresponding phase coil of the DC brushless motor to a respective on of positive and negative terminals of a DC power supply.

Abstract: The invention relates to a combined device and method for powering and charging, that comprises an AC motor (6), a converter (2), storage means (5), and switching means (4) either for enabling the powering of the motor (6) or for enabling the charging of the storage means (5) by the converter. The device includes means for compensating the magnetic fields generated during the charge of the storage means (5) in order to limit or prevent the movements of the motor (6) rotor.

Abstract: A power starting circuit used in a DC power supply circuit has a double-pole, double-throw switch electrically connected to a positive pole of a DC power supply and controls a conducting state of the circuit. A first capacitor provides a voltage signal for a first switch circuit and controls the conducting state of the first switch circuit in a continuous charging and discharging process. The first switch circuit controls the conducting state of the DC power supply circuit. A maintaining signal input end provides a maintaining signal for the first capacitor. The power starting circuit can achieve an over discharge protection function for the control circuit. Moreover, when the switch is turned on, it can automatically switch the circuit off so as to save power if the electrical product does not need to continue to work.

Abstract: Protection of a motor controller from a transient voltage and/or an over-voltage condition is described. A drive circuit includes a rectifier portion and at least one inductive device coupled to the rectifier portion. The drive circuit further includes at least one voltage clamping device coupled in parallel with the at least one inductive device, and at least one switching device configured to open as a function of a direct current (DC) link voltage value.

Abstract: A motor control apparatus includes a power conversion unit which supplies drive power to a motor, a current detection unit which detects the value of a current flowing from the power conversion unit to the motor, a delta-sigma modulation AD converter to which the current value detected by the current detection unit is input as analog data, and which includes a modulator and a plurality of digital low-pass filters and outputs digital data in accordance with the filter characteristics of the respective digital low-pass filters, and a command generating unit which is connected to the digital low-pass filter to be used for motor drive control among the plurality of digital low-pass filters, and which generates a drive command to the power conversion unit by using the digital data output from the motor drive controlling digital low-pass filter.

Abstract: A circuit disconnection element that can open or short-circuit between a power storage element and a step-up/step-down bidirectional chopper circuit is provided in a power storage system, thereby preventing a self-discharge state in a process of charging. Furthermore, at the time of occurrence of an abnormality, the power storage element is detached from other devices including the step-up/step-down bidirectional chopper circuit. Accordingly, an energy loss of the power storage element at the time of power regeneration can be reduced to improve the energy use efficiency. Further, breakage influences such that the power storage element causes breakage in other devices at the time of occurrence of the abnormality can be prevented, thereby enabling to obtain an AC motor drive device having mounted therein a highly safe power storage system.

Abstract: A method of braking a washing machine from an operational speed to a reduced non-zero speed is provided (as well as a washing machine incorporating the method) for a washing machine driven by one of a synchronous or asynchronous motor. Upon receipt of a speed reduction signal, the motor rotating magnetic fields are collapsed for a defined time period. After the defined time period, DC braking voltage is applied to the motor stator windings at a controlled ramp-up rate to an amplitude to generate a controlled ramped braking torque on the motor until the motor has slowed to a defined reduced speed. Thereafter, the amplitude of the DC braking voltage is set to 0V and the motor is soft started to an amplitude and reduced frequency needed to maintain the defined reduced speed.

Abstract: In an abnormality diagnosing system for first and second current sensors for measuring a current, an obtaining unit obtains at least one pair of measured values of the first and second current sensors. The at least one pair of measured values is measured by the first and second current sensors at a substantially same timing. A diagnosing unit diagnoses whether there is an abnormality in at least one of the first and second current sensors based on a function defining a relationship between the at least one pair of measured values of the first and second current sensors.

Abstract: The invention relates to a switch arrangement of an electric motor drive (1). The electric motor drive comprises safety switches (3) determined by the safety of the drive, a controlled mechanical brake (4), a power supply circuit (5) of the brake control, a power converter (6), which power converter comprises a network rectifier (7) and a power rectifier (8) of the motor. The power rectifier of the motor is at least partly implemented with controlled semiconductor switches (9, 10) arranged into a bridge. The power converter comprises an intermediate circuit (11, 12) between the network rectifier and the power rectifier of the motor. The switch arrangement comprises normally-open switches (13, 14) in the intermediate circuit of the power converter (6).

Abstract: An electric brake circuit for holding an alternating current motor rotor stationary uses a direct current brake acting on an AC motor rotor. The rotor has at least one groove formed therein positioned for alignment with at least one AC motor pole when switching from an alternating current to DC. The AC induction motor holds the rotor stationary against a heavier load by using the grooved rotor with the grooves formed in the rotor aligning with the AC motor's poles.

Abstract: A converter system and method, including: at least one supply module, which provides a unipolar, intermediate circuit voltage; one or more drive modules, which may be powered from the intermediate circuit voltage and each include at least one inverter for powering at least one electric motor; and at least one buffer module for storing energy.

Abstract: There is provided an inverter capable of reducing a speed in a short period of time without generating an overcurrent even in a case of an alternating current motor which is easy to be saturated magnetically. A frequency of driving a motor is calculated by using a detecting value constituted by passing a direct current bus line voltage through a first filter portion, a voltage command is corrected by using a detecting value passing through a second filter portion, by making a time constant of the second filter portion larger than a time constant of the first filter portion in reducing a speed, the motor is brought into an overexcited state and loss is brought about in the motor.

Abstract: An electric brake circuit for holding an alternating current motor rotor stationary uses a direct current brake acting on an AC motor rotor. The rotor has at least one groove formed therein positioned for alignment with at least one AC motor pole when switching from an alternating current to DC. The AC induction motor holds the rotor stationary against a heavier load by using the grooved rotor with the grooves formed in the rotor aligning with the AC motor's poles.

Abstract: A system, method, and article of manufacture for determining parameter values associated with an electrical grid in accordance with an exemplary embodiment is provided. The electrical grid has a point of interconnection where the electrical grid is electrically coupled to a power source. The method includes measuring real power at the point of interconnection of the electrical grid to obtain a plurality of real power values. The method further includes measuring reactive power at the point of interconnection of the electrical grid to obtain a plurality of reactive power values. The method further includes measuring a voltage at the point of interconnection of the electrical grid to obtain a plurality of voltage values. The method further includes estimating at least one parameter value associated with the electrical grid utilizing the plurality of real power values, the plurality of reactive power values, and the plurality of voltage values, and a mathematical estimation technique.

Abstract: A method and apparatus for braking an AC motor in the higher portion of its speed range includes substantially reducing flux before applying reverse torque commands to brake the motor. A DC link bus regulator is employed to prevent increases in bus voltage and frequency.

Abstract: A battery-powered vehicle for transporting a mined payload or supplies over the roadways existing in or around an underground mine, includes variable voltage, variable frequency drivers that convert DC voltage from a battery into an AC voltage for driving AC induction motors of a front wheel drive system of the vehicle, and a further variable frequency driver that converts DC voltage from the battery into an AC voltage for driving an AC pump motor for supplying hydraulic fluid to hydraulically operated components of the vehicle. A controller controls the operation of the variable voltage variable frequency drivers in response to commands supplied to the controller by an operator of the vehicle.

Abstract: A current detection unit of an inverter outputs currents to a load, such as a motor includes a device for measuring a DC current flowing in the inverter. The current detection unit also includes a measurement time setting device for setting a measurement time of power source currents at at least one of an uppermost point and a lowest point of a reference chopping wave with a predetermined frequency, and a current phase detection means for detecting at least two phase currents from respective power source currents measured at two or more measurement times sequential to each other. A phased current output from the inverter to a load, such as a motor, may be detected with a high degree of accuracy and at a constant period.

Abstract: A novel architecture of high-power four-quadrant hybrid power modules based on high-current trench gate IGBTs and arrays of low-current wide-bandgap diodes is conceived. The distributed physical layout of high power density wide-bandgap devices improves the cooling inside a fully-sealed module case, thus avoiding excessive internal heat flux build up and high PN junction temperature, and benefiting the converter's reliability and efficiency. The design of multiple-in-one hybrid integrated AC-switch module at high power ratings is enabled by using hybrid AC switch cells and aluminum nitride substrate structure.

Abstract: An apparatus for anti-islanding protection of a distributed generation with respect to a feeder connected to an electrical grid is disclosed. The apparatus includes a sensor adapted to generate a voltage signal representative of an output voltage and/or a current signal representative of an output current at the distributed generation, and a controller responsive to the signals from the sensor. The controller is productive of a control signal directed to the distributed generation to drive an operating characteristic of the distributed generation out of a nominal range in response to the electrical grid being disconnected from the feeder.

Abstract: A regenerative converter for a DC motor (55) having an armature (A, B) and a field (57), comprises a conventional three-phase matrix converter (6) including a three-phase bridge (7), the output of two phases being connected (52, 53) across the armature of the motor, the third phase being connected (58) to one end (I) of the DC motor field (57). The other end (K) of the DC motor field (57) is connected (59a) through a plurality of diodes (61-63) to respective phases of the input power.

Abstract: An electric trailer brake controller includes a deceleration sensor for generating a brake control signal. The controller also includes a device to decrease the sensitivity of the deceleration sensor to spurious inputs. Additionally, the controller includes a brake current limiting circuit that progressively reduces the current supplied to the controlled trailer brake when the brake current exceeds a predetermined level.

Abstract: The invention in the simplest form is a method and apparatus for reliably protecting against island situations with one or multiple power sources connected to an electric distribution grid. The method and apparatus detects variations in the voltage and frequency of the grid. An observed change in grid voltage causes a change in output power that is sufficient to cause an even larger change in grid voltage when the utility AC power source is disconnected. An observed change in grid frequency causes a change in phase or reactive output power that is sufficient to cause an even larger change in grid frequency. If several shifts in voltage or frequency happen in the same direction, the response to the change is increased in an accelerating manner.

Abstract: An electric drive apparatus and method for controlling medium-voltage alternating current motors wherein a multi-phase power transformer having multiple secondary windings provides multi-phase power to multiple power cells which provide four quadrant operation. Each power cell has a single-phase output and is controllable by a modulation controller. The power cells are connected in series thus permitting the maximum output voltage for each cell to be less than the maximum line-to-line voltage. Each power cell can have a rectifier portion to convert input AC-to-DC, capacitors, an output DC-to-AC inverter, a regenerative bridge converter connected in parallel with the rectifier portion and a local modulation controller connected to a master controller.

Abstract: The chopping power controller reduces switching error due to the noise in the current detected signal. The chopping power controller includes a switching member (18a) for supplying power to an electric load (1a) and a current sensor (2) for detecting electric current flowing through the electric load (1a). The detected electric current is compared by a comparator (16a, 30a) to a target value. The output from the comparator is supplied to a filter (23) for outputting identical signal (k) as the comparator (16a, 30a) after the comparator (16a, 30a) keeps the same level signal for a period of time. The switching member (18a) is turned off when the detected electric current continuously exceeds the target value for the period of time set at the filter (23). The filter (23) may removes the noise which has a shorter period than that of the filter (23). In other words, the filter (23) removes high frequency noise from the comparator (16a, 30a) in order to turn off the switching member (18a) accurately.

Abstract: The invention relates to a method of ensuring the stability of a synchronous machine in controlling the synchronous machine on the basis of direct control of flux and torque, in which the torque generated by the synchronous machine is increased/decreased by increasing/decreasing the instantaneous angular velocity of the stator flux. In accordance with the invention, the method comprises the steps of determining the direction of the stator flux vector (.psi.s) in rotor coordinates (dq), and forcing the stator flux vector (.psi.s) to remain in quadrants I and IV (Q1, Q4) of the rotor coordinates by rotating the stator flux in the rotor coordinates to a necessary degree.

Abstract: Disclosed is a method of controlling an internal combustion engine driven electric vehicle in power operation of the vehicle, in which control is made so that a voltage of a DC intermediate circuit is maintained to a first constant DC voltage in a first speed range of from a zero vehicle speed to a first vehicle speed, the voltage of the DC intermediate circuit is changed in proportion to the vehicle speed in the second speed range of from the first vehicle speed to a second vehicle speed, and the voltage of the DC intermediate circuit is made to be a second constant DC voltage in the third speed range not lower than the second vehicle speed, and control is further made so that an AC output of the second power converter is made to have a variable voltage and a variable frequency in the first and second speed ranges, while the AC output of the second power converter is made to have a constant voltage and a variable frequency in the third speed range.

Abstract: Disclosed is a method of controlling an internal combustion engine driven electric vehicle in power operation of the vehicle, in which control is made so that a voltage of a DC intermediate circuit is maintained to a first constant DC voltage in a first speed range of from a zero vehicle speed to a first vehicle speed, the voltage of the DC intermediate circuit is changed in proportion to the vehicle speed in the second speed range of from the first vehicle speed to a second vehicle speed, end the voltage of the DC intermediate circuit is made to be a second constant DC voltage in the third speed range not lower than the second vehicle speed, and control is further made so that an AC output of the second power converter is made to have a variable voltage and a variable frequency in the first and second speed ranges, while the AC output of the second power converter is made to have a constant voltage and a variable frequency in the third speed range.

Abstract: A unity power factor power supply for an electric motor. A switch-mode circuit is employed which, in a first mode, transfers power from AC main to a constant voltage DC bus. In a second mode, power generated on the DC bus is fed back to the main power supply. The circuit of the invention automatically maintains the DC bus voltage constant and sets an adequate operation mode by processing the DC bus voltage signal. In both operation modes, the unity power factor and sinusoidal waveform of the AC main side are maintained.

Abstract: In an electric system for an electric vehicle, DC power of a main battery is converted into AC power by an inverter which has a power regenerative function. At startup, the system charges an input smoothing capacitor on the DC side of the inverter through an initial charging circuit with an initial charging switch and resistor. A main circuit switch that can stop current is connected between the main battery and the inverter. A rheostatic braking circuit with a rheostatic braking switch and a braking resistor is connected to the DC input side of the inverter for rheostatic breaking when required. Rheostatic braking takes over after regenerative braking when the main battery loses its power absorption capability, with the main circuit switch off. Semiconductors can be used as switches, and can be placed on a cooling body or modularized. Low-noise wires can be used to reduce noise.

Abstract: A motor drive includes an invertor (5) with which a motor (6) is rotated at a variable speed. To suppress noises caused by ripple components contained in currents flowing in phase coils of the motor, the invertor (5) is controlled so as to direct a commuting current flowing from the phase coils to a d.c. power source (1) and at a time when the motor is decelerating to circulate in a path including the phase coils and the switching transistors of the invertor (5). This control is performed when the commuting currents fall below a predetermined level.

Abstract: An apparatus comprising, in combination, an AC motor, a solid state switch controlling the AC motor, the solid state switch switchable between an on state in which an electric current flows through the solid state switch and an off state in which electric current does not flow through the solid state switch, the solid state switch characterized by a turn off time such that, when the solid state switch is switched between the on state and the off state, at least a portion of the electric current flows through the solid state switch during the turn off time, a first switch circuit for switching off the solid state switch to prevent the electric current from flowing to the AC motor, a diode bridge coupled across the AC motor, a second switch circuit for controllably switching the diode bridge between an active state in which electric current may flow through the diode bridge and an inactive state in which electric current may not flow through the diode bridge, a control circuit for controlling the second switch

Abstract: A procedure and apparatus for the measurement of the currents in a frequency converter, provides that the phase currents of the frequency converter are measured by storing, in memory, signals corresponding to the current of the d.c. circuit of the converter and by producing a current value corresponding to the phase current from the previous and the momentary signals.

Abstract: An electric automobile driving apparatus installed in an electric automobile for driving the same. The driving force of the electric automobile is generated by a main battery as the rotating force of a motor. The motor is an AC motor and driven by an AC current output from the main battery and converted into a DC voltage by an inverter. Electric appliances installed in the automobile are driven by a DC voltage having a different value which is output from an auxiliary battery. The auxiliary battery is charged with the DC voltage obtained by rectifying the output from a secondary coil which is disposed in close proximity to a primary coil of the motor.

Abstract: A disc record/reproduce apparatus with a brushless dc motor having no separate dedicated position sensor, controls rotation of the dc synchronous motor by back-electromotive force signals developed in windings of the brushless dc motor using a/d converter included in one-chip microprocessor in the first mode, and controls by position and index signals recorded on the disc in the second mode. During start-up, a start-up oscillator is used. The control with a back-electromotive force signal is provided to enable the microprocessor to write a position signal on a disc and provided for inspecting the brushless dc motor independently. In the second mode, functions for executing the back-electromotive force control in the microprocessor is disabled during recording and reproducing of data to prevent overload on the microprocessor which is busy because of communication with an external computer and control of head position.

Abstract: A DC braking system for an inverter-driven induction motor, (e.g., three-phase). When a braking command occurs, the normal gating sequence of the inverter stops. Mode 1 of the braking procedure starts. In Mode 1, two semiconductor phase switches of the group connected with one of the DC buses and the semiconductor switch of the third phase that is connected with the other DC bus are latched in a conducting state. The motor essentially receives DC current, which increases until it actuates a current limit device, clearing the latch. Then all six switches are turned off. That drives the motor current through the back-biased parallel diodes. The negative DC bus voltage is available to suppress motor current despite large motor speed voltages. The apparatus repeats the Mode 1 procedure for a predetermined time interval, after which Mode 2 of the braking procedure starts. In Mode 2, just as in Mode 1, two switches of one bus and one switch of another bus conduct until an overcurrent limit is reached.

Abstract: A bridge between the inductor and the capacitor of the DC-Link of a voltage-source inverter AC motor drive includes a GTO (or transistor) device used for forced-commutation in the regenerating mode, while the current is controlled ON and OFF according to a duty-cycle defined by an hysteresis circuit to hold the current flowing into the inductor to a magnitude which establishes a boost on the capacitor voltage, so that in the motoring, as well as the regenerating mode of operation, the voltage of the capacitor is kept constant and higher than upon the converter output.

Abstract: A power supply regenerating circuit according to the present invention is used in an inductor motor drive circuit which performs motor drive control and regenerative control. The induction motor drive circuit has a parallel circuit including a reverse connected diode (D10) and a resistor (R1) connected between a circuit (C2), which rectifies and then smoothes the induced electromotive force of an induction motor (M) during deceleration, and a bridge circuit (Tr1-Tr6) which effects a conversion into AC power. Regenerative power blocked by the diode (D10) is supplied to the bridge circuit (Tr1-Tr6) as a current limited by the resistor (R1), and the regenerative power is regenerated only during a predetermined interval of a three-phase period.

Abstract: For connecting the d-c terminals of a voltage-source inverter to a direct current (d-c) power source, a d-c link capacitor is connected directly between the d-c terminals, a line capacitor is connected in parallel with the d-c link capacitor, and a series inductor is connected between the line capacitor and the source. A dynamic brake resistor and an electric power chopper are connected in series with one another across the line capacitor. Between the two capacitors, no inductance is provided but a resistor is inserted in the braking current path during electrical braking operation of the inverter.

Abstract: An apparatus for controlling an adjustable-speed alternating current motor coupled to drive an elevator cage. The apparatus includes a converter connected to a source of AC power for converting the AC power into DC power, an inverter connected through relatively positive and negative conductors to the converter for inverting the DC power into DC output power having adjustable frequency, voltage magnitude, and current magnitude to drive the motor, and a control circuit for controlling an inverter to drive the motor at an adjustable speed. When a power failure occurs, the control circuit prevents flow of power through the converter to the power source and reduces the current magnitude of the inverter output power to a predetermined minimum limit enough to maintain a synchronous relationship between the inverter and the motor.