A method for controlling a variable speed drive supplying power to an electric motor, the variable speed drive comprising a plurality of at least Ni low-voltage power cells connected in series, comprising: upon reception of a speed command, determining a number Mi of cells sufficient to supply power to the motor at a target voltage V that is determined based on the speed command; and activating the Mi power cells from among the Ni power cells, and deactivating the Ni-Mi other power cells in order to supply power to the motor in accordance with the speed command.

Disclosed herein is a method for controlling an electrical converter system that includes: determining a nominal pulse pattern (t.sub.p,i*, Δu.sub.p,i*) and a reference trajectory (x*) of at least one electrical quantity of the electrical converter system over a horizon of future sampling instants, the nominal pulse pattern (t.sub.p,i*, Δu.sub.p,i*) comprises switching transitions (Δu.sub.p,i*) between output voltages of an electrical converter of the electrical converter system and the reference trajectory (x*) indicates a desired future development of an electrical quantity of the converter system; determining a small-signal pulse pattern (ũ.sub.abc(t, λ.sub.p,i)) by minimizing a cost function; determining a modified pulse pattern (t.sub.opt,p,i, Δu.sub.p,i) by moving the switching transitions of the nominal pulse pattern (t.sub.p,i*, Δu.sub.p,i*) to generate modified switching transitions; and applying at least the next switching transition of the modified pulse pattern (t.sub.opt,p,i, Δu.sub.p,i) to the electrical converter system.

Disclosed herein is a method for controlling an electrical converter system that includes: determining a nominal pulse pattern (t.sub.p,i*, Δu.sub.p,i*) and a reference trajectory (x*) of at least one electrical quantity of the electrical converter system over a horizon of future sampling instants, the nominal pulse pattern (t.sub.p,i*, Δu.sub.p,i*) comprises switching transitions (Δu.sub.p,i*) between output voltages of an electrical converter of the electrical converter system and the reference trajectory (x*) indicates a desired future development of an electrical quantity of the converter system; determining a small-signal pulse pattern (ũ.sub.abc(t, λ.sub.p,i)) by minimizing a cost function; determining a modified pulse pattern (t.sub.opt,p,i, Δu.sub.p,i) by moving the switching transitions of the nominal pulse pattern (t.sub.p,i*, Δu.sub.p,i*) to generate modified switching transitions; and applying at least the next switching transition of the modified pulse pattern (t.sub.opt,p,i, Δu.sub.p,i) to the electrical converter system.

An electric motor may comprise a rotor and a stator. One or more first cables connected to a first power converter circuit of are wrapped adjacent to at least some stator teeth of a stator core to form at least a first portion of one or more coil windings. One or more second cables connected to a second power converter circuit of the plurality of power converter circuit also may be wrapped adjacent to at least some of the stator teeth to form at least a second portion of the one or more coil windings.

An electric motor may comprise a rotor and a stator. One or more first cables connected to a first power converter circuit of are wrapped adjacent to at least some stator teeth of a stator core to form at least a first portion of one or more coil windings. One or more second cables connected to a second power converter circuit of the plurality of power converter circuit also may be wrapped adjacent to at least some of the stator teeth to form at least a second portion of the one or more coil windings.

Ina power conversion system having a fixed pulse pattern modulation unit 2 that is configured to refer to tables storing therein pulse patterns that determine respective command voltage levels corresponding to phase information for each modulation ratio and to generate a gate signal g on the basis of a command modulation ratio d and a control phase θ and driving a power converter 3 on the basis of the gate signal g, the fixed pulse pattern modulation unit 2 is further configured to, when performing a pulse pattern transition, search for a proper post-transition table reference position and make a command voltage level follow a command voltage level of a post-transition pulse pattern. With this, the power conversion system that can perform the pulse pattern transition without current impulse and that can also be applied to a multi-level power converter having four levels or more can be provided.

A system includes a controller for a DC to AC inverter including a processor configured to execute instructions to perform operations including: generating a first pulse for a first phase of a center-aligned PWM signal to alternately activate a first phase switch of a first switch group of the inverter for a first duration and a first phase switch of a second switch group of the inverter for a second duration within a period of the PWM signal; and generating a second pulse for a second phase of the PWM signal to alternately activate a second phase switch of the first switch group of the inverter for a third duration and a second phase switch of the second switch group of the inverter for a fourth duration within the period of the PWM signal, wherein the second duration is different from the third duration during a stall condition.

A system includes a controller for a DC to AC inverter including a processor configured to execute instructions to perform operations including: generating a first pulse for a first phase of a center-aligned PWM signal to alternately activate a first phase switch of a first switch group of the inverter for a first duration and a first phase switch of a second switch group of the inverter for a second duration within a period of the PWM signal; and generating a second pulse for a second phase of the PWM signal to alternately activate a second phase switch of the first switch group of the inverter for a third duration and a second phase switch of the second switch group of the inverter for a fourth duration within the period of the PWM signal, wherein the second duration is different from the third duration during a stall condition.

A motor driving apparatus includes: a first inverter including: a plurality of first switching elements and connected to a first end of each of the windings; a second inverter including: a plurality of second switching elements and connected to a second end of each of the windings; and a controller configured to control a switching state of the plurality of first switching elements and the plurality of second switching elements based on a driving mode of the motor in one sampling period.

Method of controlling a multi-level inverter having inputs connected to a gate drive unit controlling the inverter and an output connected to a load, the multi-level inverter capable of generating a PWM voltage signal having three or more modulation levels, the inverter powered by a voltage supply and comprising at least one neutral point (NP), the method comprising operating the multi-level inverter in a standard modulation pattern having three or more modulation levels when one or more parameters representative of neutral point stability each have a value within a first range indicative of a high neutral point stability, and operating the multi-level inverter with a two-level modulation pattern when said one or more parameters representative of neutral point stability each have a value within a second range indicative of a low neutral point stability, the first range separated from the second range by a threshold value.