Elevator power management system having power storage apparatus maintaining a particular charge in accordance with time of day
First Claim
1. An elevator power management system, the system comprising:
- a power storage apparatus;
a converter for rectifying AC electric power from a power source into DC electric power for operating an elevator and for charging said power storage apparatus;
an inverter for inverting DC electric power from said converter and from said power storage apparatus into AC electric power having a variable voltage and a variable frequency for driving the elevator;
a motor driven by the AC electric power to operate the elevator; and
charge/discharge control means coupled to said converter, said inverter, and said power storage apparatus for controlling charging and discharging of said power storage apparatus based upon a charge target value of said power storage apparatus, stored in said charge/discharge control means, and that varies with time of day.
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Accused Products
Abstract
To reduce total power required to drive an elevator by a commercial power supply during a peak power-consumption time period, for instance, an afternoon in summer time, a control apparatus includes a converter for rectifying AC electric power into DC electric power; an inverter for inverting the DC electric power into AC electric power having a variable voltage and a variable frequency; a motor driven by the AC electric power having the variable voltage and the variable frequency to operate an elevator; a power storage apparatus for storing electric power; and a charge/discharge control for controlling charging and discharging operation of the power storage apparatus based upon a charging target value.
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Citations
8 Claims
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1. An elevator power management system, the system comprising:
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a power storage apparatus;
a converter for rectifying AC electric power from a power source into DC electric power for operating an elevator and for charging said power storage apparatus;
an inverter for inverting DC electric power from said converter and from said power storage apparatus into AC electric power having a variable voltage and a variable frequency for driving the elevator;
a motor driven by the AC electric power to operate the elevator; and
charge/discharge control means coupled to said converter, said inverter, and said power storage apparatus for controlling charging and discharging of said power storage apparatus based upon a charge target value of said power storage apparatus, stored in said charge/discharge control means, and that varies with time of day. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8)
the charge target value is lower during a peak power-consumption time period than during other time periods; and
said charge/discharge control means controls the charging and discharging of said power storage apparatus in accordance with the charge target value.
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3. The elevator power management system as claimed in claim 1 wherein the charge target value is set to a maximum within a time period just before a peak power-consumption time period, and is gradually decreased during the peak power-consumption time period.
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4. The elevator power management system as claimed in claim 1 wherein the charge target value is gradually increased during periods of minimal operation of the elevator, and becomes a maximum at a time before full scale operation of the elevator.
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5. The elevator power management system as claimed in claim 1 wherein the charge target value corresponds to at least a charge amount of said power storage apparatus sufficient to operate the elevator in an emergency.
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6. The elevator power management system as claimed in claim 1 wherein when charge of the power storage apparatus is smaller than the charge target value, discharging of said power storage apparatus is stopped.
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7. The elevator power management system as claimed in claim 1 wherein when the elevator is stopped, said power storage apparatus is charged with the AC electric power and the AC electric power is supplied from a commercial power supply.
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8. The elevator power management system as claimed in claim 1 wherein when said power storage apparatus is charged using the AC electric power from a commercial power supply, current from the commercial power supply is limited.
Specification