A system is provided with a set of removable battery packs and a set of power tools each including a motor, a controller, and a battery receiving portion. For each power tool, the controller is configured to identify a type of battery pack coupled to the battery receiving portion and limit a maximum amount of electric current drawn from the battery pack by the motor based on the identified type of the battery pack. The greater a ratio of an impedance of the motor to an impedance of the battery pack, the less the controller limits the maximum amount of electric current drawn from the battery pack such that for a given battery pack of the set of removable battery packs, the lower the impedance of the motor, the more current the motor draws from the given battery pack.

A compressor control apparatus includes a rectifier configured to rectify AC power to DC power; an inverter including a plurality of switching elements, configured to convert the DC power into a three-phase voltage according to a pulse width modulation (PWM) signal applied to the plurality of switching elements; a motor configured to receive a three-phase current based on the three-phase voltage; a current detector configured to detect a sum of a first phase current, a second phase current, and a third phase current supplied to the motor; and a controller configured to differently determine a duty ratio of the PWM signal applied to each of the plurality of switching elements, and to determine the first phase current, the second phase current, and the third phase current, respectively, based on the determined duty ratio and the sum of the currents detected from the current detector.

A compressor control apparatus includes a rectifier configured to rectify AC power to DC power; an inverter including a plurality of switching elements, configured to convert the DC power into a three-phase voltage according to a pulse width modulation (PWM) signal applied to the plurality of switching elements; a motor configured to receive a three-phase current based on the three-phase voltage; a current detector configured to detect a sum of a first phase current, a second phase current, and a third phase current supplied to the motor; and a controller configured to differently determine a duty ratio of the PWM signal applied to each of the plurality of switching elements, and to determine the first phase current, the second phase current, and the third phase current, respectively, based on the determined duty ratio and the sum of the currents detected from the current detector.

A power conversion device includes an inverter, a current detector, a frequency analysis processor, a storage, a determination unit, a reference rotational rate change unit, and a rate controller. The determination unit determines a frequency at which a signal component having a magnitude exceeding a prescribed value has been detected among frequency components of a load current, generates restriction information for excluding a reference rotational rate for a rotational rate corresponding to the detected frequency based on a determination result after the determination, and causes the storage to store the generated restriction information. The reference rotational rate change unit changes a reference rotational rate of an electric motor so that mechanical resonance of the detected frequency is avoided based on the stored restriction information. The rate controller controls a rotational rate of the inverter using the changed reference rotational rate. The electric motor is driven at the controlled rotational rate.

A current detection unit includes current detection elements provided to phases on a high potential side of an upper arm element or on a low potential side of a lower arm element. A detection target element is the upper arm element or the lower arm element to which the current detection elements are provided. A target duty is a duty ratio of the detection target element. The control unit includes a current acquisition unit, an energization control unit, and an abnormality determination unit. The current acquisition unit acquires a current detection value from the current detection unit. The abnormality determination unit performs an abnormality determination based on the current detection value. The abnormality determination unit varies a determination threshold, which is used for the abnormality determination based on the current detection value, according to the target duty.

Systems and methods of the present disclosure enable drive filtering with reduced common mode and differential mode harmonics using a drive filter including, common-differential mode inductors connected to an alternating current (AC) power source, where each common-differential mode inductor has a common mode inductance and a differential mode inductance. A differential mode capacitor is connected to each common-differential mode inductors for filtering the differential mode inductances. A first common mode capacitor is connected to each common-differential mode inductor for filtering the common mode inductances, where each first common mode capacitor are commonly connected. A second common mode capacitor is connected to each common-differential mode inductor for filtering the common mode inductances, where each second common mode capacitor are commonly connected. Output contacts are connected to the common-differential mode inductors to connect a load to the AC power source.

A motor control device including a PWM control part is provided. The PWM control part has a two-phase complementary PWM control part, and when driving opening and closing of an opening/closing body, PWM-controls upper switching elements and lower switching elements of three phases in a three-phase inverter circuit based on an energization mode that sequentially switches among energized phases, which are two of the three phases, and a non-energized phase, which is a remaining one phase. The two-phase complementary PWM control part, in one of the energized phases, controls one of the upper switching element and the lower switching element by a PWM signal, and controls the other by a complementary PWM signal having a polarity opposite to the PWM signal, and, in the non-energized phase, controls one of the upper switching element and the lower switching element to be off, and controls the other by the complementary PWM signal.

A motor control device including a PWM control part is provided. The PWM control part has a two-phase complementary PWM control part, and when driving opening and closing of an opening/closing body, PWM-controls upper switching elements and lower switching elements of three phases in a three-phase inverter circuit based on an energization mode that sequentially switches among energized phases, which are two of the three phases, and a non-energized phase, which is a remaining one phase. The two-phase complementary PWM control part, in one of the energized phases, controls one of the upper switching element and the lower switching element by a PWM signal, and controls the other by a complementary PWM signal having a polarity opposite to the PWM signal, and, in the non-energized phase, controls one of the upper switching element and the lower switching element to be off, and controls the other by the complementary PWM signal.

An electric machine comprising a first and a second three-phase winding and comprising a stator formed of a cylindrical yoke made of a soft ferromagnetic material extended radially by a set of teeth, a portion of the set of teeth bearing the windings, the windings being distinct from one another, the first three-phase winding being connected in a delta configuration, the second three-phase winding being connected in a star configuration.

An electric machine comprising a first and a second three-phase winding and comprising a stator formed of a cylindrical yoke made of a soft ferromagnetic material extended radially by a set of teeth, a portion of the set of teeth bearing the windings, the windings being distinct from one another, the first three-phase winding being connected in a delta configuration, the second three-phase winding being connected in a star configuration.