US 6,439,347 B2Granted

Elevator control apparatus controlling charging of a power source with regenerative power

AssigneesMitsubishi Denki Kabushiki Kaisha, The Tokyo Electric Power Company, Incorporated

InventorsIkuro Suga, Hiroshi Araki, Shinobu Tajima, Kazuyuki Kobayashi

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Abstract

An elevator control apparatus includes: a converter for rectifying AC power into DC power; an inverter for converting the DC power into AC power having a variable voltage and a variable frequency; a controller for controlling a motor based on the AC power having the variable voltage and the variable frequency, operating an elevator; a power storage unit for storing the DC power; a required power computing circuit for computing required power of the elevator based on a speed command of the controller; a charge/discharge control circuit for issuing a drive signal for changing charge current, supplied to the power storage unit, based on regenerative electric power so as to charge the power storage unit with the regenerative electric power if the required power of the elevator is negative, meaning that the regenerative electric power is available; and a charge/discharge circuit for charging the power storage unit with the regenerative electric power in accordance with the drive signal. Thus, regenerative electric power can be effectively used, contributing to energy savings.

Claims4

Dependent claims

An elevator control apparatus comprising:

a converter for rectifying AC power to produce DC power;
an inverter for converting DC power into AC power having a variable voltage and a variable frequency;
DC buses connecting the converter to the inverter;
a power storage unit connected across the DC buses for storing DC power and for supplying DC power to the buses;
a controller for controlling a motor operating an elevator, the motor being driven by the AC power having variable voltage and variable frequency, during a powered operation of the elevator and generating power during a regenerative operation of the elevator;
a required power computing circuit for computing required power as power required by the elevator based on a speed command for controlling speed of the elevator and supplied to the controller and, through the controller, to the required power computing circuit;
a charge/discharge control circuit maintaining a bus voltage across the buses, at a preset voltage, not less than a voltage obtained by rectifying the AC power, receiving the bus voltage as a feedback input and receiving the required power computed as another input, and issuing a drive signal for charging the power storage unit with regenerative electric power if the power required by the elevator is negative, meaning regenerative electric power is being generated by the motor;
and
a charge/discharge circuit for charging the power storage unit with the regenerative electric power in accordance with the drive signal.

6 more elements

An elevator control apparatus comprising:

a converter for rectifying AC power to produce DC power;
an inverter for converting DC power into AC power having a variable voltage and a variable frequency;
DC buses connecting the converter to the inverter;
a power storage unit connected across the DC buses for storing DC power and for supplying DC power to the buses;
a controller for controlling a motor operating an elevator, the motor being driven by the AC power having variable voltage and variable frequency, during a powered operation of the elevator and generating power during a regenerative operation of the elevator;
a current sensor for sensing charging current being supplied to the power storage unit and a voltage sensor for sensing the voltage of the power storage unit;
a charge/discharge control circuit maintaining the bus voltage at a preset voltage, receiving the charging current and voltage sensed as inputs, issuing a drive signal for charging the power storage unit with regenerative electric power generated by the motor, controlling the charging current supplied to the power storage unit so the charging current may reach, but not exceed, an upper limit value, and issuing a drive signal for continuing charging of the power storage unit with regenerative electric power at a constant current less than the upper limit value after the voltage of the power storage unit reaches a preset voltage, whereby power storage by the power storage unit is maximized;
and
a charge/discharge circuit for charging the power storage unit with the regenerative electric power in accordance with the drive signal produced by the charge/discharge control circuit.

6 more elements

Dependencies are inferred from the claim text.