Apparatus and methods for controlling electric motors are disclosed. In addition, such apparatus and methods for starting and controlling electric motors and controlling electric motors switching from a PWM control to six step method of control. Methods and apparatus are further included to provide for robust control of an electric motor operating in a six-step running mode.

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.

A method of controlling a drive including one respective inverter associated with each of a plurality of servomotors in a robot. The method includes providing a PWM frequency corresponding to a frequency of switching instances for respective semiconductor switches in each of the inverters, whereby for each inverter time is divided into consecutive control cycles forming a sequence of control cycles of the inverter, each control cycle containing two, and only two, of the switching instances for each of the semiconductor switches. The method also includes spreading the respective control cycle sequences of the inverters over time such that the control cycles of each inverter are time shifted in respect to the control cycles of each of the other inverters in the power converter.

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.

Two inverters provided at both ends of each open-end winding, respectively, are appropriately controlled. A rotating electrical machine control device (1) that has at least two control schemes among pulse width modulation control, active short-circuit control, and rectangular-wave control, as control schemes for a first inverter (11) and a second inverter (12), and that can control the first inverter (11) and the second inverter (12) by control schemes which are independent of each other considers one of the plurality of control schemes as a first control scheme and one of the plurality of control schemes different than the first control scheme as a second control scheme, and has a control mode in which the first inverter (11) is controlled by the first control scheme and the second inverter (12) is controlled by the second control scheme.

Systems and methods for increasing Pulse Width Modulation (PWM) resolution for digitally controlled motor control applications are described. For example, in some embodiments, a method may include receiving a clock signal having a given period; identifying a target duty cycle; calculating a comparison point based upon the given period and the target duty cycle; generating a PWM signal based upon the clock signal using the comparison point; and varying the comparison point to increase a resolution of an effective duty cycle of the PWM signal.

Apparatus and methods for controlling electric motors are disclosed. In addition, such apparatus and methods for starting and controlling electric motors and controlling electric motors switching from a PWM control to six step method of control. Methods and apparatus are further included to provide for robust control of an electric motor operating in a six-step running mode.

An electric working machine in one aspect of the present disclosure includes a motor and a controller. The motor is configured to be electrically coupled to a battery pack and to be driven with electric power from the battery pack. The controller is configured to acquire an internal resistance information of the battery pack and to change control of the motor based on the internal resistance information acquired.

An electric working machine in one aspect of the present disclosure includes a motor and a controller. The motor is configured to be electrically coupled to a battery pack and to be driven with electric power from the battery pack. The controller is configured to acquire an internal resistance information of the battery pack and to change control of the motor based on the internal resistance information acquired.

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.