摘要:
A security apparatus adapted to a power converter, including a power converting circuit connected between a DC power source and an AC system; a phase detector circuit for detecting the voltage phase of the AC system to provide a phase detection signal; a reference signal generator circuit for generating a voltage reference in accordance with the phase detection signal; a control circuit for controlling an output voltage of the power converting circuit in accordance with the voltage reference. The security apparatus is characterized by a disturbance generator circuit for applying a disturbance to the phase detector circuit; and a detector circuit for detecting an abnormal state in which the phase or frequency of the output voltage of the power converting circuit deviates from a normal one.
摘要:
In a PWM control type power supply apparatus, a modulation (high frequency) signal component is eliminated from an AC output. The PWM control type power supply apparatus includes: AC-to-DC converting means coupled to an AC (alternating current) power source capable of supplying a first AC voltage having a low frequency from a pair of output terminals, for converting the first AC voltage to obtain a positive DC (direct current) voltage from a positive half cycle of the first AC voltage appearing at one output terminal and a negative DC voltage from a negative half cycle of the first AC voltage appearing at one output terminal with a common voltage appearing at the other output terminal; and, DC-to-AC inverter means including a pair of first and second switching elements, and a PWM (pulse width modulation) controller for controlling switching operations of the first and second switching elements in a PWM control mode so as to invert the positive and negative DC voltage into a second AC voltage having a modulation frequency higher than the low frequency with respect to the common voltage output terminal, whereby the second AC voltage contains no modulation frequency component.
摘要:
In a PWM control type power supply apparatus, a modulation (high frequency) signal component is eliminated not only from AC input, but also AC output. The PWM control type power supply apparatus includes: an AC-to-DC converting unit capable of supplying a first AC voltage having a source frequency from a pair of output terminals, for converting the first AC voltage to obtain a positive DC (direct current) voltage from a positive half cycle and a negative DC voltage from a negative half cycle of the first AC voltage appearing at one output terminal with a common voltage appearing at another output terminal; a DC-to-AC inverter unit including a pair of first and second switching elements, and a PWM (pulse width modulation) controller for controlling switching operations of the first and second switching elements in a PWM control mode so as to invert the positive and negative DC voltage into a second AC voltage having a modulation frequency higher than the source frequency the second AC voltage being applied to a load; and a choke coil having a single core and first, second and third coil windings wound on the single core for magnetically coupling the coil windings with each other, the first and second coil windings being interposed between the AC power source and the AC-to-DC converting means, and also the third coil winding being interposed between the DC-to-AC inverter unit and the load.
摘要:
In a PWM control type power supply apparatus, there are provided a single-phase full-wave rectifier coupled to a power source having a low frequency, for rectifying a first AC (alternating current) voltage to produce a DC (direct current) voltage; a DC-to-AC inverter including a first pair of switching elements connected to an input terminal thereof, and a second pair of switching elements connected to an output terminal thereof and to the first pair of switching elements to constitute a bridge inverter circuit, for inverting the DC voltage into a second AC voltage to be applied to a load; and a switching controller connected to the DC/AC inverter for alternately turning ON/OFF the second pair of switching elements in response to a sync signal (SYC) in synchronism with the first AC voltage at the low frequency of the power source, and for alternately turning ON/OFF the first pair of switching elements in response to a PWM (pulse-width modulation) control signal obtained from the first AC voltage and the second AC voltage, in a PWM control mode at a high-frequency higher than the low frequency of the power source, whereby a phase of the second AC voltage is opposite to that of the first AC voltage.