Converter circuit having control means with capability to short-circuit converter output
First Claim
1. A converter circuit comprising:
- a reactor connected to an AC power supply;
a PWM converter circuit connected to the reactor, said PWM converter circuit having a high speed diode, a rectifier diode and a switching element connected in parallel to the rectifier diode;
an input current detection means for detecting an input current of said PWM converter circuit;
a DC voltage detection means for detecting an output voltage of said PWM converter circuit;
a voltage level detection means connected to said AC power supply, said detection means detecting whether or not an input voltage is at a constant level; and
a control means for measuring a variation period of a detection result of the voltage level detection means to judge a power supply frequency and for controlling said PWM converter circuit based on a judgment result for the power supply frequency, a detection result from said voltage level detection means, an input current detected by said input current detection means, and an output voltage detected by said DC voltage detection means.
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Accused Products
Abstract
A converter circuit has a reactor connectable to an AC power supply. It further has a PWM converter circuit connected to the reactor, the PWM converter circuit including a high speed diode, a rectifier diode and a switching element connected in parallel to the rectifier diode. The converter circuit further has an input current detector for detecting an input current of the PWM converter circuit, a DC voltage level detector for detecting an output voltage of the PWM converter circuit, a voltage polarity detector connected to the AC power supply, and a control device. The control device measures a variation period of the output voltage measured by the voltage level detector to judge a power supply frequency. It then controls the PWM converter circuit based on a power supply frequency judgement result, a detection result from the voltage level detector, an input current detected by the input current detector, and an output voltage detected by the DC voltage detector.
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Citations
18 Claims
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1. A converter circuit comprising:
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a reactor connected to an AC power supply;
a PWM converter circuit connected to the reactor, said PWM converter circuit having a high speed diode, a rectifier diode and a switching element connected in parallel to the rectifier diode;
an input current detection means for detecting an input current of said PWM converter circuit;
a DC voltage detection means for detecting an output voltage of said PWM converter circuit;
a voltage level detection means connected to said AC power supply, said detection means detecting whether or not an input voltage is at a constant level; and
a control means for measuring a variation period of a detection result of the voltage level detection means to judge a power supply frequency and for controlling said PWM converter circuit based on a judgment result for the power supply frequency, a detection result from said voltage level detection means, an input current detected by said input current detection means, and an output voltage detected by said DC voltage detection means. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 17, 18)
said input current detection means has a current transformer using a lead from said AC power supply as a primary side; and
said control means uses a value gained by letting a secondary side output of said current transformer pass through a frequency characteristic correction means and an absolute value conversion means as a detection input current (|Iac|), and uses a multiplication result between an absolute value of an input voltage wave form or an absolute value of said sine-wave and a value based on an error of said output voltage as an input current set value (|Iac|*).
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17. A converter circuit according to claim 4 wherein, in the case of carrying out consecutive measurement and operation of a rise time Ton of the detection result of said voltage polarity detection means and a fall time Toff of the detection result of said voltage polarity detection means, the same condition is confirmed for n times continuously for each PWM control period of said PWM converter circuit to perform the calculation by advancing a time corresponding to (n−
- 1) times of said PWM control periods while carrying out said operation processing.
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18. A converter circuit according to claim 5 wherein, in the case of carrying out consecutive measurement and operation of a rise time Ton of the detection result of said voltage polarity detection means and a fall time Toff of the detection result of said voltage polarity detection means, the same condition is confirmed for n times continuously for each PWM control period of said PWM converter circuit to perform the calculation by advancing a time corresponding to (n−
- 1) times of said PWM control periods while carrying out said operation processing.
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9. A boost-type converter circuit comprising a reactor connectable to an AC power supply and a control means for charging current in said reactor by short circuiting a converter output with a switching element and for outputting current charged in said reactor through a diode by turning off said switching element,
said control means being provided, with respect to an error between an output DC voltage and its set value, with an integration operational function of the error and a proportion operational function of the error so that said control means sums outputs of said two operational functions and utilizes the resulting sum to determine an amplitude of an input current set value, and wherein when the error exceeds a certain value, said control means fixes the output of said integration operational function to a present value by forcing said switching element to turn off.
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10. A boost-type converter circuit comprising a reactor connectable to an AC power supply and a control means for charging current in said reactor by short circuiting a converter output with a switching element and for outputting current charged in said reactor through a diode by turning off said switching element,
said control means being provided, with respect to an error between an output DC voltage and its set value, with an integration operational function of the error and a proportion operational function of the error so that said control means utilizes a multiplication result between a sum of outputs of said two operational functions and an absolute value of a voltage wave form of said AC power supply to determine an input current set value, and wherein when the input current set value based on the error exceeds a certain value, said control means uses a predetermined value for limitation.
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11. A boost-type converter circuit comprising a reactor connectible to an AC power supply and a control means for charging current in said reactor by short circuiting a converter output with a switching element and for outputting current charged in said reactor through a diode by turning off said switching element,
said control means being provided, with respect to an error between an output DC voltage and its set value, with an integration operational function of the error and a proportion operational function of the error so that said control means utilizes a multiplication result between a sum of outputs of said two operational functions and an absolute value of a voltage wave form of said AC power supply to determine an input current set value, and said control means detects an absolute value of input current to gain an error between the absolute value and the input current set value for performing one of a proportional integration-type characteristics operation having an integral characteristic at low frequency with respect to the error between the absolute value and the input current set value, and a proportional integration type characteristics operation having an integral characteristic at a low frequency and having a flat characteristic at a high frequency, so as to gain on- and off-duties of said switching element.
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12. A boost-type converter circuit comprising a reactor connectible to an AC power supply and a control means for charging current in said reactor by short circuiting a converter output with a switching element and for outputting current charged in said reactor through a diode by turning off said switching element,
said control means being provided, with respect to an error between an output DC voltage and its set value, with an integration operational function of the error and a proportion operational function of the error so that said control means utilizes a multiplication result between a sum of outputs of said two operational functions and an absolute value of a voltage wave form of said AC power supply to determine an input current set value, and said control means detects an absolute value of input current to gain an error between the absolute value and the input current set value for performing one of a proportional integration-type characteristics operation having an integral characteristic at low frequency with respect to the error between the absolute value and the input current set value, and a proportional integration type characteristics operation having integral characteristics at low frequency and having a moving averaging characteristic at high frequency, so as to gain on- and off-duties of said switching element.
Specification