Elevator control apparatus controlling charging of a power source with regenerative power
First Claim
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1. 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.
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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.
39 Citations
4 Claims
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1. An elevator control apparatus comprising:
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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.
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2. An elevator control apparatus comprising:
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a converter for rectifying AC power to produce DC power;
an inverter for covering 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;
a charge/discharge control circuit maintaining a bus voltage between the converter and the inverter at a preset voltage, not less than a voltage obtained by rectifying the AC power, monitoring the charging current supplied to the power storage unit from the regenerative electric power generated by the motor with the current sensor, and issuing a drive signal stopping charging of the power storage unit with the regenerative electric power when the charging current reaches zero; and
a charge/discharge circuit stopping charging of the power storage unit with the regenerative electric power in accordance with the drive signal.
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3. An elevator control apparatus comprising:
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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. - View Dependent Claims (4)
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Specification
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Current AssigneeMitsubushi Denki Kabushiki Kaisha
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Original AssigneeMitsubishi Denki Kabushiki Kaisha (Mitsubishi Electric Corporation), Tokyo Electric Power Company
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InventorsKobayashi, Kazuyuki, Araki, Hiroshi, Suga, Ikuro, Tajima, Shinobu
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Primary Examiner(s)SALATA, ANTHONY J
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Application NumberUS09/771,931Publication NumberTime in Patent Office574 DaysField of Search187/247, 187/290, 187/293, 187/296, 187/297, 318/375, 318/376, 318/377, 318/743, 318/727, 318/759, 318/798-815, 320/109, 320/121, 320/153US Class Current187/290CPC Class CodesB66B 1/285 with the use of a speed pat...B66B 1/30 effective on driving gear ,...
