A motor drive apparatus includes an AC stabilized power supply configured to convert AC voltage of a commercial AC power source into input power supply voltage according to a received voltage command value and output the input power supply voltage, a converter configured to convert the input power supply voltage into DC voltage and output the DC voltage to a DC link, an inverter configured to convert the DC voltage at the DC link into AC voltage for driving a motor, and an input power supply voltage control unit configured to control the input power supply voltage that is output by the AC stabilized power supply.

A solid-state circuit breaker (SSCB) with self-diagnostic, self-maintenance, and self-protection capabilities includes: a power semiconductor device; an air gap disconnect unit connected in series with the power semiconductor device; a sense and drive circuit that switches the power semiconductor device OFF upon detecting a short circuit or overload of unacceptably long duration; and a microcontroller unit (MCU) that triggers the air gap disconnect unit to form an air gap and galvanically isolate an attached load, after the sense and drive circuit switches the power semiconductor device OFF. The MCU is further configured to monitor the operability of the air gap disconnect unit, the power semiconductor device, and other critical components of the SSCB and, when applicable, take corrective actions to prevent the SSCB and the connected load from being damaged or destroyed and/or to protect persons and the environment from being exposed to hazardous electrical conditions.

A circuit for detecting a status of a ground connection in an electric motor includes a rectifier, a converter, a voltage conditioning circuit, a leakage circuit, and a comparator. The rectifier couples to an AC line within the motor and generates a first DC voltage. The converter steps-down the first DC voltage to a second DC voltage. The voltage conditioning circuit couples to the converter, leakage circuit, and comparator, and generates a reference DC voltage signal and a leakage voltage from the second DC voltage. The leakage circuit includes an impedance coupled to ground, and applies the leakage voltage to the impedance and generates a measurement signal representing a leakage current through the impedance to ground. The comparator couples to the leakage circuit and generates a logic signal, indicating a status of the ground connection, based on a voltage difference between the reference DC voltage signal and the measurement signal.

Fault-tolerant electrical drive systems and methods of maintaining electrical balance or continuing operation of a rotary electric machine under a fault condition are provided. One such system comprises: a rotary electric machine comprising pn phases having a common connection point, where p is a prime number and n is an integer greater than or equal to 1; a drive circuit module having pn phase drive circuits and a reserve drive circuit; and a contactor module. The contactor module comprises: pn phase contactors each of which is operable to connect one of the pn phases of the rotary electric machine to a respective one of the pn phase drive circuits; and a phase fault contactor operable to connect the reserve drive circuit to the common connection point.

A torque-limiting safety circuit servo drive for AC permanent magnet motors including a three-phase inverter bridge, a first current sensor in series with a first motor phase, a second current sensor in series with a second motor phase, a third current sensor in series with the DC bus, and a drive control circuit that controls the six pulse-width modulated gate drive signals for the three-phase inverter bridge. The drive circuit has first and second safety channel STO inputs whereby either channel can shut down the three-phase inverter bridge, emits a signal set to represent the switching state of the three-phase inverter bridge, and modifies the switching pattern of the PWM to ensure the dwell times of PWM is sufficiently long to allow a valid measurement of phase current using the bus current sensor. First and second safety processors controls the first and second safety channel STO inputs, respectively.

In accordance with an embodiment, a method includes using a monitoring circuit disposed on a monolithic integrated circuit to monitor an output signal of a first switching transistor for a first output edge transition at a monitoring terminal of the monolithic integrated circuit; using a time measuring circuit disposed on the monolithic integrated circuit to measure a first time delay between a first input edge transition of a first drive signal and the first output edge transition, where the first drive signal is configured to cause a change of state of the first switching transistor; using an analysis circuit disposed on the monolithic integrated circuit to compare the measured first time delay with a first predetermined threshold to form a first comparison result; and indicating a first error condition based on the first comparison result.

A motor drive includes a rectifier bridge for connection with mains, a converter bridge configured to connect with an elevator motor and an intermediate DC circuit in-between. A capacitor and/or battery is connected between positive and negative branches of the intermediate DC circuit. At the mains side of the rectifier bridge a controlled main relay with contacts are configured to connect or disconnect the rectifier bridge with the corresponding mains phase. The motor drive comprises a charging circuit which comprises a charging switch connected with a current limiting component. The motor drive comprises a voltage sensor between positive and negative branches of the intermediate DC circuit. The voltage sensor is connected to a circuit comprising a reference value and a comparator. The evaluation circuit is configured to compare the actual sensor signal of the voltage sensor to the reference value and to operate the main relay based on the comparison.

A drive circuit for driving a switching element on a SiC substrate, includes: a comparator for comparing a current flowing through the switching element with an overcurrent threshold; a determination unit for determining whether an overcurrent flows, based on a comparison result; a control unit for generating a drive signal for controlling a drive operation of the switching element based on a drive command, and for turning off the switching element when determining that the overcurrent flows; and a setting unit for variably setting the overcurrent threshold according to a physical quantity correlated with a voltage between main electrodes of the switching element.

The invention relates to a motor drive for monitoring operational measurement data (34) of an electric motor (12) having at least one operating point (78, 80, 82, 84), wherein the electric motor (12) is configured to drive a load (21), the motor drive (10) comprising a measurement unit (14) for acquiring initial measurement data (118) for at least one of the operating points (78, 80, 82, 84) of the electric motor (12), wherein the initial measurement data comprises sensor data and/or estimated data; a processing unit (26) for determining a baseline (58, 60, 62, 64) from the initial measurement data (118) for the at least one operating point (78, 80, 82, 84); an output unit (28); characterized in that the processing unit (26) is configured to generate at least one threshold level (36, 38, 40) for the at least one determined baseline (58, 60, 62, 64), while the electric motor (12) is on an on state or an off state; wherein the at least one threshold level (36, 38, 40) defines a level of deviation from the determined baseline (58, 60, 62, 64), wherein the output unit (28) is configured to provide the at least one threshold lev-el (36, 38, 40) resulting in conditions for monitoring the operational measurement data (34) of the electric motor (12). The invention provides an improved motor drive (10) for monitoring operational measurement data (34) of a electric motor (12) that are more accurate than in the prior art.

In accordance with an embodiment, a method includes using a monitoring circuit disposed on a monolithic integrated circuit to monitor an output signal of a first switching transistor for a first output edge transition at a monitoring terminal of the monolithic integrated circuit; using a time measuring circuit disposed on the monolithic integrated circuit to measure a first time delay between a first input edge transition of a first drive signal and the first output edge transition, where the first drive signal is configured to cause a change of state of the first switching transistor; using an analysis circuit disposed on the monolithic integrated circuit to compare the measured first time delay with a first predetermined threshold to form a first comparison result; and indicating a first error condition based on the first comparison result.