Abstract: A motor control system includes an inverter, and a control calculation unit that feedback-controls the inverter. The control calculation unit includes a voltage control calculation unit that calculates a voltage command value indicating a voltage to be applied to the motor from the inverter on the basis of a current deviation between a current command value and an actual current detection value, a torque ripple compensation calculation unit that adds a compensation value for compensating a torque ripple in the motor to a signal value on at least one of an upstream side and a downstream side in a signal flow that passes through the voltage control calculation unit, and a current limit calculation unit that limits the current command value by adaptive control based on an actual angular velocity value indicating an angular velocity at which the motor rotates.

Abstract: A pulse voltage generator calculates a corrected pulse voltage application time. The pulse voltage generator also outputs, for the duration of the corrected pulse voltage application time, a voltage vector closest to a rotor phase from among twelve voltage vectors as a voltage vector command. A current detector detects three-phase output currents of a power converter, which are obtained when first to sixth switching elements of the power converter are turned on or off on the basis of the voltage vector command. A three-phase/two-phase converter converts the three-phase output currents to two-phase output currents to output d-axis current. When the d-axis current after the corrected pulse voltage application time has elapsed becomes less than or equal to a demagnetization determination threshold value, a demagnetization determiner determines that demagnetization occurs in a permanent magnet of a rotor of a motor.

Abstract: A method of calibrating a motor assembly includes selecting an electric motor and a motor controller for the motor assembly, obtaining at least one electric motor parameter of the electric motor, calculating a correction factor for the electric motor based upon the at least one electric motor parameter, and programming the motor controller with the correction factor.

Abstract: A rotating electrical machine control system (100) whose control target is an alternating-current rotating electrical machine (80) including M coil sets (8) includes M inverters (50) each including a plurality of switching elements (5) and connected to a direct-current power supply (41) and one of the coil sets (8) to convert electric power between a direct current and alternating currents of N phases; M current sensors (6) each provided for each coil set (8) to detect an alternating current of each phase flowing through the coil set (8); and an inverter control device (30) that generates switching control signals (S) for controlling the plurality of switching elements (5). The inverter control device (30) performs current feedback control of the rotating electrical machine (80) using all detection values for each of N phases obtained by the M current sensors (6), to generate the switching control signals (S) common to the M inverters (50).

Abstract: To provide a controller for motor which can reduce a torque ripple up to high frequency, without amplifying unnecessary noise and vibration. A controller for motor estimates an interlinkage flux based on the applied voltage and the detection value of current; estimates an output torque based on the detection value of current and the estimation value of interlinkage flux; extracts a pulsation component from the estimation value of output torque; calculates a voltage command correction value based on the extraction value of pulsation component; calculates a voltage command after superimposing by superimposing the voltage command correction value on the voltage command basic value; and applies voltage to winding based on the voltage command after superimposing.

Abstract: In sensorless control for a rotary machine, when variations in inductances for U, V, W phases due to manufacturing error are great, imbalance occurs among detected currents for the respective phases. Thus, estimation error of a magnetic pole position of a rotor increases, so that positioning accuracy is reduced. Correction filters for imparting gains in accordance with rotary machine constants for the respective phases are provided to control means or magnetic pole position calculation means, thereby correcting the imbalance occurring among the detected currents for the respective phases.

Abstract: A motor drive control device includes a control circuit configured to output a drive control signal for driving a motor, and a drive circuit configured to drive the motor with the drive control signal. The control circuit calculates a lead angle value ? allowing a d-axis current value Id of a two-phase rotating coordinate system to be zero with a q-axis current value Iq calculated from drive current values Iu, Iv, and Iw of a coil of the motor and rotation speed ? of a rotor of the motor. The control circuit performs a space vector conversion based on an angle ? obtained by adding the lead angle value ? and rotation angle ? and voltage command value Vref of the two-phase rotating coordinate system calculated to reduce a difference between the q-axis current value Iq and a q-axis current command value Iqref, to generate the drive control signal.

Abstract: A rotating machine control device for controlling a rotating machine having a stator winding and a field winding includes a current command generation unit which generates a current command value on the basis of the temperature of the rotating machine. The current command generation unit includes a constraint condition setting unit which calculates a constraint condition on the basis of a torque command, stator winding voltage, stator winding current, and field winding current, an optimization calculation unit which calculates and outputs the current command value, using the constraint condition and an evaluation function, and a constraint condition update unit which updates the constraint condition on the basis of the temperature of the rotating machine. The current command generation unit calculates and outputs the current command value, using the updated constraint condition.

Abstract: A method is for use with a synchronous machine having a stator and a rotor with or without permanent magnets. In operation, electric current of the synchronous machine responsive to the synchronous machine being actuated via clocked terminal voltages is measured. A magnetic flux linkage is determined based on the clocked terminal voltages and the measured electric current. A profile of the magnetic flux linkage as a function of rotation of the rotor, under a boundary condition of an at least two-dimensional electric current vector that is unchanged in coordinates of the stator, is used to detect a position of the rotor. The synchronous machine is controlled according to the rotor position.

Abstract: A method, system, and apparatus are provided for determining mechanical characteristics of an electric motor and mechanical load with a speed signal modulator, FOC current loop, sensor-less rotor speed estimator, and speed signal demodulator which are configured to provide a q-axis AC reference current, q-axis DC reference current, estimated maximum AC rotor speed, estimated DC rotor speed, estimated phase angle of the AC rotor speed component, and torque constant to a mechanical characteristics estimator which is configured to determine a plurality of load torque parameters for the electric motor and mechanical load which include a combined moment of inertia parameter, a combined static friction, and a combined viscous friction coefficient parameter.

Abstract: Described is a method of controlling operation of a synchronous motor. The method comprises, during constant power/speed motor operation, determining a value of a stator voltage (vs2) for an orthogonal rotating reference frame of the motor. Comparing the value of the determined stator voltage (vs2) to a threshold voltage (vs2_max1), said threshold voltage (vs2_max1) having a value between that of a maximum stator voltage (vs2_max0) for a basic speed mode of operation of the motor and that of a maximum stator voltage (vs2_max2) of the motor closed loop controller. If the determined value of the stator voltage (vs2) is greater than or equal to the value of the threshold voltage (vs2_max1), then controlling operation of the motor in a flux weakening mode of operation until a value of a current component (id??id) in a d-axis reaches a maximum negative value (?idmax), or until the value of the stator voltage (vs2) is less than the value of the threshold voltage (vs2_max1).

Abstract: Control of an AC motor includes rotation over an operating speed range with the output from an inverter by operating the inverter at switching frequencies that vary in proportion to rotor speed. The operating speed range is parsed into a plurality of speed regions and the switching frequencies within each operating speed region may correspond to a respective pulse ratio that is different from the respective pulse ratio corresponding to an adjacent speed region.

Abstract: A speed estimating device for an AC motor includes: a model deviation computing unit computing a model deviation based on a voltage, a current, and an estimated angular velocity of the AC motor; a first angular velocity estimating unit computing a first estimated angular velocity based on the model deviation; a second angular velocity estimating unit computing a second estimated angular velocity differing from the first estimated angular velocity in frequency, based on the model deviation; a compensation phase computing unit computing a compensation phase based on a disturbance frequency; and an estimated angular velocity calculator computing an estimated angular velocity of the AC motor based on the first estimated angular velocity and the second estimated angular velocity. Either one of the first estimated angular velocity and the second estimated angular velocity is computed based on the compensation phase.

Abstract: A method of calibrating a motor assembly includes selecting an electric motor and a motor controller for the motor assembly, obtaining at least one electric motor parameter of the electric motor, calculating a correction factor for the electric motor based upon the at least one electric motor parameter, and programming the motor controller with the correction factor.

Abstract: A method for sensorless control of an electric motor implemented in a variable speed drive including: determining a control voltage to be applied to the motor; injecting a high frequency signal to the control voltage to obtain an excitation voltage, wherein one or more frequencies of the high frequency signal varies with time; applying the excitation voltage to the motor; measuring a current signal induced in the motor by the excitation voltage, wherein the current signal comprises a fundamental current, induced by the control voltage, and a disturbance current, induced by the high frequency signal; and demodulating the current signal.

Abstract: The present disclosure relates to a cooking apparatus and a method of controlling the same, and more particularly, to a technology for reducing stress caused by a current flowing through a diode included in the cooking apparatus.

Abstract: A method for controlling operation of a rotary electric machine includes receiving, via a bandwidth-partitioning harmonic compensation regulator (HCR) of a controller, a commanded torque and rotational speed of the electric machine, and calculating, via the HCR in response to enabling conditions, a dq harmonic compensation current and a dq harmonic compensation voltage for one or more predetermined harmonic orders using the commanded torque and the rotational speed. The harmonic compensation current and voltage cancel torque ripple and current ripple in the one or more predetermined harmonic orders. The method may include injecting an acoustic tone at a predetermined harmonic order. The method additionally includes adding the dq harmonic compensation current and voltage to a dq current and voltage command, respectively, to generate adjusted dq current and voltage commands. The electric machine is then controlled using the adjusted dq current and voltage commands.

Abstract: A motor control device controls a current of a motor based on a torque command, the current being separated into a d-axis current and a q-axis current orthogonal to the d-axis current, the torque command being a target value of a torque of the motor.

Abstract: The invention relates to a method and device for operating an electric machine (10) for outputting a predefined torque and a predefined rotational speed, comprising the following steps: providing (420) a first and a second operating mode for the operation of the electric machine (10); detecting (430) a temperature of the electric machine (10); and operating the electric machine (10) in the first operating mode (440) if the detected temperature falls below a threshold value, and operating the electric machine (10) in the second operating mode (450) if the detected temperature corresponds with the threshold value or exceeds same.

Abstract: A memory motor winding multiplexing control method and system for flux linkage observation. The method comprises the following steps: I: when the magnetization state of a memory motor needs to be adjusted, selecting a flux regulation current reference value according to a rotation speed of the motor; II: by means of current feedback control, driving a direct-current flux regulation winding to generate a flux regulation current so as to adjust the magnetization state of a permanent magnet; III: when the memory motor is operating normally, collecting an induction voltage of the flux regulation winding and extracting an induced electromotive force of the flux regulation winding; and IV: using the induced electromotive force of the flux regulation winding to calculate the flux linkage of the permanent magnet for vector control of the motor.

Abstract: The present disclosure disclose a vector flux weakening control system for a permanent magnet synchronous motor of an electric drive system, which includes a current closed-loop regulation module, a modulation index deviation calculation module, a current characteristic point setting module, a current compensation vector angle calculation module, a current compensation vector amplitude calculation module, a current compensation vector calculation module and a current instruction correction module.

Abstract: A generator system can include a generator configured to produce an output of alternating current (AC), a rectifier connected to the generator to rectify the AC into direct current (DC) rectifier output, an inverter connected to the rectifier to receive the DC rectifier output and configured to output three phase AC inverter output, and a plurality of output lines connected to the inverter to receive the three phase AC inverter output. The system can include a control module configured to control the output of the inverter. The control module can be operatively connected to one or more of the output lines via one or more local sense leads to receive a local feedback. The control module can be configured to control the inverter as a function of the local feedback to provide one or more of protection, voltage regulation, or harmonic correction.

Abstract: Disclosed are a motor control device that can accurately estimate a rotor position based on a neutral point potential even when a load increases, and a brake control device that is driven by the motor control device. The motor control device 3 includes a three-phase synchronous motor 4 including a three-phase winding, an inverter 31 connected to the three-phase winding, a control unit 6 for controlling the inverter based on a rotor position of the three-phase synchronous motor, and a rotational position estimation unit 2 for estimating a rotor position ?d based on a neutral point potential Vn of the three-phase winding. The rotational position estimation unit estimates a rotor position selectively using one or more of a plurality of detected values of the neutral point potential according to a pre-estimated value of the rotor position and a voltage application state to the three-phase winding.

Abstract: A power conversion device includes a harmonic voltage generation unit that superimposes dc-axis and qc-axis harmonic voltages on dc-axis and qc-axis voltage commands in accordance with a switching signal; and an inductance estimation unit that estimates dc-axis inductance and qc-axis inductance on a basis of dc-axis and qc-axis harmonic currents, amplitude values of the harmonic voltages, and the switching signal.

Abstract: Provided is an electric motor control apparatus (1) configured to extract a speed ripple component from a difference between an angular frequency command and an angular frequency feedback, configured to generate a phase of the speed ripple component from the speed ripple component, configured to multiply a value of a periodic function corresponding to the phase and a given amplitude by each other, to thereby generate a torque compensation value, configured to calculate a torque command value from the difference between the angular frequency command and the angular frequency feedback, and configured to control a current to be output to an electric motor based on a compensated torque command obtained by adding the torque compensation value to the torque command value.

Abstract: In a loaded condition, the controller increases at least one of the conduction band or the advance angle from a baseline value up to a maximum value within a first torque range below a torque threshold to as to maintain the output speed of the motor at a linear speed-torque profile. After the at least one of the conduction band or the advance angle reaches the maximum value, the controller maintains the at least one of the conduction band or the advance angle at the maximum value within a second torque range greater than or equal to the torque threshold so as to maintain the output speed of the motor at a naturally-curved speed-torque profile.

Abstract: An electric motor includes a rotor including a first rotor end and a second rotor end, and a stator including a first stator end and a second stator end. The first rotor end is located apart from the first stator end toward the first side. The second rotor end is located apart from the second stator end toward the first side. The relationship between the distances D1 and D2 satisfies D1>D2?0, where D1 is a distance from a permanent magnet to a first end plate, and D2 is a distance from the permanent magnet to a second end plate. The thickness of each of a plurality of electrical steel sheets is not less than 0.1 mm and not more than 0.25 mm.

Abstract: A noise reduction system for a marine vessel having a plurality of marine propulsion devices including a first marine propulsion device and a second marine propulsion device, each of the plurality of marine propulsion devices including a drive source, each of the drive sources operating on a same principle as that of the other drive sources, and including a rotary member. The noise reduction system includes a controller configured to control rotation of the rotary member of the drive source in the second marine propulsion device, to thereby control a phase of a second noise caused thereby, such that a first noise caused by rotation of the rotary member of the drive source in the first marine propulsion device is canceled by the second noise.

Abstract: A rotation electric machine controller includes: a torque command value acquisition section that acquires a torque command value for a rotation electric machine; and a setting section that sets a negative limit value limiting a d-axis current command value. The setting section sets the limit value having a larger absolute value in a case where the torque command value is large, in comparison to a case where the torque command value is small.

Abstract: A motor control device includes: a second setting unit configured to set an armature current command value and a current phase angle command value based on a rotation speed and a motor torque command value; and a current vector setting unit configured to set a d-axis current command value and a q-axis current command value based on the armature current command value and the current phase angle command value. The second setting unit is configured to set the armature current command value and the current phase angle command value such that an armature current vector which is set based on the d-axis current command value and the q-axis current command value is included in an area surrounded by an armature current vector locus in maximum torque/current control and a vertical axis in a d-q coordinate system.

Abstract: A power tool is provided including a brushless motor having a stator defining a plurality of phases and a rotor. A power unit is provided including power switches and a control unit outputs a drive signal to the motor switches to drive the phases of the motor using a trapezoidal control scheme over a series of sectors. The control unit sets a conduction band within which each phase is commutated to a baseline value that is greater than 120 degrees, sets at least one commutation transition point as a function of the set conduction band, and within each sector, monitors an open-phase voltage of the motor to detect a back electromotive force (back-EMF) voltage of the motor and control commutation of at least one phase based on the open-phase voltage of the motor in relation to the at least one commutation transition point.

Abstract: For motor stator resistance calculation, a method estimates an output voltage using a Direct Current (DC) bus voltage and a duty ratio for a motor drive at a first switching frequency and at least one second switching frequency. The method measures an output current at the first switching frequency and the at least one second switching frequency. The method calculates a first stator resistance for the first switching frequency and at least one second stator resistance for the at least one second switching frequency. The method estimates a stator resistance at a DC condition based on the first stator resistance and the at least one second stator resistance. The method sets a dynamic compensation based on a stator resistance error between the first switching frequency and the at least one second switching frequency.

Abstract: Disclosed herein are a motor control apparatus and method. The motor control apparatus includes a compensation signal generator configured to apply a DC-Link voltage (VLink) for driving a motor to a parameter map preset in order to estimate a gain and phase of a motor torque ripple generated when the motor is driven according to a motor command current and a motor rotation speed, and to generate a compensation signal (icomp) for compensating for the motor torque ripple corresponding to a current input motor command current (iq*), motor rotation speed (?m), and DC-Link voltage (VLink), and a current controller configured to control the current of the motor by controlling an inverter such that a compensation command current (iq*_comp), generated by reflecting the compensation signal (icomp), in the motor command current (iq*), coincides with a motor drive current (iq) supplied to the motor from the inverter.

Abstract: The invention relates to a method for determining the position (?R) and the rotational speed (nR) of a rotor of an electrical machine during an active short circuit and a rotor-state determining device (10) designed to carry out the method.

Abstract: A control device applies voltages to an AC rotating machine based on voltage command values on stationary coordinates. Currents in a plurality phases flowing the rotating machine are detected as detection currents. Coordinate conversion is applied to those detection currents based on any phase in the rotating machine, for generate detection currents on rotational coordinates. Voltage command values on the rotational coordinates are generated based on current command values on the rotational coordinates and the detection currents. Coordinate conversion is applied to those voltage command values based on the any phase, for generate first voltage command values on the stationary coordinates. Phases of one of the first voltage command values and generated second voltage command values on the stationary coordinates are corrected to generate the second voltage command values. One of the second and the first voltage command values are selected as the voltage command values on the stationary coordinates.

Abstract: An inverter controller is configured to control an inverter circuit that drives an on-vehicle electric motor by using an on-vehicle electricity storage device. The inverter controller includes a two-phase voltage command value deriving unit that derives two-phase voltage command values on the basis of an external command value delivered from an external device and an acquisition result of a speed acquiring unit, and a three-phase voltage command value deriving unit that derives three-phase voltage command values on the basis of the two-phase voltage command values. The three-phase voltage command value deriving unit derives the three-phase voltage command values on the basis of a voltage utilization factor, which is calculated on the basis of the two-phase voltage command values and the acquisition result.

Abstract: A method of determining an electrical angle offset of a motor position sensor mounted to a multi-phase electric motor, the method comprising rotating a rotor of the multi-phase electric motor at a motor velocity using an external drive system, measuring a motor phase voltage of each phase of the multi-phase electric motor, the motor phase voltage comprising a back-EMF generated by the rotation of the motor, converting the motor phase voltage to a DQ reference frame to form a DQ motor phase voltage and calculating the electrical angle offset from the DQ motor phase voltages.

Abstract: Provided is a control device for a rotating machine including a magnetic pole position estimation unit, a vector calculation unit, a current command correction unit configured to correct a first d-axis current command and a first q-axis current command, to thereby output a second d-axis current command and a second q-axis current command, a voltage application unit configured to superimpose a high-frequency voltage including a specific frequency component on voltage commands on rotational coordinates. The magnetic pole position estimation unit is configured to estimate the position of the magnetic pole based on a state quantity of the specific frequency component. The current command correction unit is configured to correct the current commands so that a current amplitude of electrical angle frequency components is equal to or larger than a half of a current amplitude of the specific frequency component.

Abstract: Provided is a motor control device capable of suppressing a sudden change in torque due to spike noise. A control device (motor control device) continues motor control using dq-axis current command values Id* and Iq* (current command values) or dq-axis detection current values real_Id and real_Iq before detecting a noise state (detection current values before a current supplied to a motor suddenly changes) instead of dq-axis detection current values real_Id and real_Iq (latest detection current values) when the current changes suddenly.

Abstract: The present disclosure relates to a DC bus discharge control method, including that: an active discharge instruction is received; a motor current signal is acquired according to the active discharge instruction; the motor current signal is converted into a current signal in a stator coordinate system; a voltage control signal in the stator coordinate system is output based on the current signal in the stator coordinate system and a random current reference instruction of a preset stator coordinate system; and the voltage control signal in the stator coordinate system is converted into a three-phase voltage control signal, and a working state of a switching device is controlled according to the three-phase voltage control signal.

Abstract: Systems and methods for detecting a current measurement gain error in a current measurement system is disclosed. The method includes reading an output voltage signal, extracting a signature of a current measurement gain error from the output voltage signal, detecting an existence of the current measurement gain error based on the signature, and responsive to detecting the existence of the current measurement gain error, identifying a diagnostic voltage phase in which the current measurement gain error exists.

Abstract: Provided is a Direct Circuit (DC) bus discharge control method, including that: an active discharge instruction is received; a motor current signal is acquired according to the active discharge instruction; the motor current signal is converted into a current signal in a stator coordinate system; a voltage control signal in the stator coordinate system is output based on the current signal in the stator coordinate system and a current reference instruction of a preset stator coordinate system, the current reference instruction of the preset stator coordinate system being a high-frequency alternating current; and the voltage control signal in the stator coordinate system is converted into a three-phase voltage control signal, and a working state of a switching device is controlled according to the three-phase voltage control signal.

Abstract: The present invention discloses a control system for an electric machine. In order to control the electric machine, predetermined frequency components are extracted from manipulated variables or measurement variables of the electric machine and are multiplied by a previously calculated control matrix. The control matrix can be calculated in advance here. Different control matrices can be formed in advance for different applications. As a result, simple efficient and robust control of the electric machine is possible, in particular for optimising and minimising harmonics.

Abstract: A driving device of one embodiment includes a phase estimator and a voltage controller. The phase estimator estimates a phase of stator interlinkage magnetic flux of an electric motor based on a current flowing through the electric motor, a voltage command of a drive voltage applied to the electric motor, and a winding resistance value of the electric motor. The voltage controller acquires a first voltage vector component in a direction in which the stator interlinkage magnetic flux acts and a second voltage vector component in a direction which is orthogonal to the direction in which the stator interlinkage magnetic flux acts for the voltage command of the drive voltage, and sets the voltage command of the drive voltage based on the first voltage vector component and the second voltage vector component.

Abstract: A thyristor starter is configured to accelerate a synchronous machine from a stop state to a predetermined rotation speed by sequentially performing a first mode of performing commutation of an inverter by intermittently setting DC output current of a converter to zero and a second mode of performing commutation of the inverter by induced voltage of the synchronous machine. The thyristor starter is further configured to raise induced voltage in proportion to the rotation speed of the synchronous machine by keeping field current constant and to suppress rise of the induced voltage by reducing the field current after the induced voltage reaches a first voltage value, in the first mode.

Abstract: The present disclosure provides an arbitrary double vector and model prediction thrust control method and system, which belongs to the technical field of linear induction motor control. The present disclosure combines a double vector modulation algorithm to improve the modulation accuracy, in which two voltage vectors are used in one cycle, so that the amplitude of the fluctuation can be reduced, thereby improving the running performance of the motor. The addition of the double vector modulation strategy increases the complexity of the algorithm, and the calculation process is too complicated. The present disclosure further proposes a simplified search process instead of the traditional repeated calculation and comparison method, which eliminates the need for a complex online calculation process, thereby simplifying the implementation process of the algorithm in the actual system.

Abstract: A device according to an embodiment includes an inverter main circuit; a detector configured to detect a current of an output line of the inverter main circuit; a starting time controller comprising a rotational phase angle estimator configured to calculate, based on a current response value detected by the detector, a value corresponding to a rotational phase angle of a motor connected to the inverter main circuit in a stationary reference frame, and a rotational speed estimator configured to calculate a value corresponding to a rotational speed of the motor by using the value corresponding to the rotational phase angle when the inverter main circuit is started; and a regular time controller configured to calculate, with the value corresponding to the rotational speed as an initial value, an estimated rotational phase angle of the motor in a rotating reference frame.

Abstract: In a motor control device that controls a sensorless-type motor, a controller estimates an initial magnetic pole position of a rotor of a motor by an inductive sensing scheme while sequentially setting a plurality of energization angles. At each of the set energization angles, the controller converts peak values of currents flowing through a plurality of phases of a stator winding into a first current component having an electrical angle that is equal to a corresponding one of the set energization angles and a second current component that is different in electrical angle by 90 degrees from the first current component, to correct the first current component based on the second current component. The controller estimates the initial magnetic pole position of the rotor based on the corrected first current component that is obtained at each of the set energization angles.

Abstract: In a motor control device in one embodiment, an initial position estimation unit estimates an initial position of a magnetic pole of a rotor of a motor in an inductive sensing scheme. At each of energization angles, the initial position estimation unit multiplies a ?-axis current component I? corresponding to a peak value of a current flowing through a stator winding by each of a cosine value and a sine value of a correction angle obtained by correcting each of the energization angles. The initial position estimation unit estimates the initial position of the magnetic pole of the rotor based on a ratio between an integrated value of a multiplication result about the cosine value and an integrated value of a multiplication result about the sine value.

Abstract: A specialized variable speed drive of the present invention is capable of controlling a motor and increasing the efficiency of both an ACIM or DCBL motor by biasing operation in favor of a class AB mode. The variable speed drive may be configured with two gate drivers where one gate driver is a class D gate driver and the second gate driver is either a class AB gate driver or a class C gate driver. The system also operates to reduce electro-magnetic interference in the operation of motors while increasing the reliability of the overall VSD system.