A control apparatus for an elevator comprising a temperature sensor which senses the temperature of the rotor of an induction motor during the stoppage of a cage, and a voltage/frequency control device which calculates the secondary winding resistance value of the induction motor on the basis of the output value of the temperature sensor and which vector-controls a power conversion device by the use of the calculated secondary winding resistance value, so that during the stoppage of the elevator, the temperature of the rotor is measured to alter the secondary winding resistance value necessary for the vector control, whereby the optimum control can be performed.

Control apparatus for elevator

Engine start capability may be added to an aircraft generating system including a variable speed, constant frequency inverter (34) by placing transistors (48) in shunt relation to diodes (22) forming part of a full wave rectifier for rectifying A.C. power from a brushless generator output winding (10) which is normally supplied to the inverter (34) for conversion to constant frequency A.C. power. A source of D.C. power (60) may be connected to the diodes (22) and transistors (48) and the latter are operated by an inverter controller (52) to convert the D.C. power so provided to alternating current to be fed to the brushless generator output windings (10) and cause the brushless generator to operate as an A.C. motor for the starting of a turbine engine (18) or the like.

Inverter operated turbine engine starting system

A three-phase induction motor control method according to the present invention subjects a three-phase induction motor to vector control by an output from an inverter which is supplied with a direct current obtained by conversion from an AC input. The method includes sensing a DC-converted voltage at a DC link section, varying a flux command in dependence upon the sensed DC voltage, and controlling the motor to obtain a constant output irrespective of a fluctuation in power supply voltage.

Three-phase induction motor control method

A power generation system is constituted by an induction generator and a converter. An output current waveform of the induction generator is determined by the magnetic flux, speed, winding impedance, DC output voltage, and load of the induction generator. In particular, the output current waveform is changed in accordance with a change in speed (i.e., change in slip). Switching elements in the converter are ON/OFF-controlled in accordance with changes in current waveform, thereby controlling power generation of the induction generator.

Power generation system having induction generator and controlled bridge rectifier

A power converter having a thyristor converter connected to an AC power source to rectify its AC output, a DC intermediate circuit including a smoothing capacitor and receiving a rectified output from the thyristor rectifier and a voltage type inverter for converting a DC voltage applied from the DC intermediate circuit into an AC output voltage of a variable voltage and a variable frequency. The DC intermediate circuit has two series circuits, each having a diode and a transistor switch, connected in parallel with each other and to the both terminals of the thyristor converter. The junctions, each between the diode and the resistor, are connected to the both terminals of the smoothing capacitor. The two series circuits function to switch the connection polarities of the thyristor converter and the smoothing capacitor and to regulate the voltage across the capacitor with a limited current by a voltage step-up or step-down operation by the transistor switch.

Power converter for driving an AC motor at a variable speed

An AC motor drive includes a power converter which supplies current to a DC bus from three-phase power lines. An inverter drives the motor from power delivered to the DC bus and it regenerates power to the DC bus when the motor is decelerated. The power converter in turn regenerates the power to the power lines by controlling line current such that it is substantially in-phase with the applied line voltages. Current overload protection is provided for the transistor switches employed in the power converter bridge circuit.

Line-regenerative motor controller with current limiter

An AC motor drive includes a power converter (10 to 53) which supplies current to a DC bus (3) from three-phase power lines (4, 5, 6). An inverter (2) drives the motor (1) from power delivered to the DC bus (3) and it regenerates power to the DC bus (3) when the motor (1) is decelerated. The power converter (10 to 53) in turn regenerates the power to the power lines (4, 5, 6) by controlling line current such that it is substantially in-phase with the applied line voltages. Current overload protection (60 to 64) is provided for the transistor switches (16 to 21) employed in the power converter bridge circuit.

Stanley P. Sassower

Papers

Line-regenerative motor controller with current limiter

A power converter for a motor control system