Frequency converter voltage pulse shaping device and method
First Claim
1. A method for controlling the shape of the rising and falling edges of AC output voltage pulses of a PWM frequency converter by reducing a speed of change of, and a height of, the AC output voltage pulse, in which the PWM frequency converter is a network bridge for rectifying the alternating voltage of the supply network into a DC voltage (UDC) of a DC intermediate circuit, which is filtered with a filtering capacitor (CDC), a load bridge comprised of phase switches implemented with power semiconductor components, which forms an AC output voltage (U, V, W) from the DC voltage of the intermediate circuit for controlling the load (M),comprising setting an average speed of voltage change of the AC output voltage pulses of at least one power component by using one of said phase switch to control the at least one power component to be conductive and non-conductive in turn for a period of at least about one microsecond to change a pulse edge of the AC output voltage pulses into at least one micropulse, andwherein the width of the at least one micropulse is controlled to increase towards a final state of said phase switch.
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Accused Products
Abstract
The shape of the rising and falling edges of AC output voltage pulses of a PWM frequency converter is controlled by reducing a speed of change, and a height, of the AC output voltage pulse. The PWM frequency converter rectifies the alternating voltage of a supply network into a DC voltage which is filtered. A load bridge having power semiconductor phase switches forms an AC output voltage from the DC voltage for controlling the load. An average speed of voltage change of AC output voltage pulses is set using a phase switch to control at least one power component to be conductive and non-conductive in turn for a period of at least about one microsecond to change a pulse edge of the AC output voltage pulses into at least one micropulse, the width of which is controlled to increase towards a final state of the phase switch.
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Citations
20 Claims
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1. A method for controlling the shape of the rising and falling edges of AC output voltage pulses of a PWM frequency converter by reducing a speed of change of, and a height of, the AC output voltage pulse, in which the PWM frequency converter is a network bridge for rectifying the alternating voltage of the supply network into a DC voltage (UDC) of a DC intermediate circuit, which is filtered with a filtering capacitor (CDC), a load bridge comprised of phase switches implemented with power semiconductor components, which forms an AC output voltage (U, V, W) from the DC voltage of the intermediate circuit for controlling the load (M),
comprising setting an average speed of voltage change of the AC output voltage pulses of at least one power component by using one of said phase switch to control the at least one power component to be conductive and non-conductive in turn for a period of at least about one microsecond to change a pulse edge of the AC output voltage pulses into at least one micropulse, and wherein the width of the at least one micropulse is controlled to increase towards a final state of said phase switch.
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5. An apparatus for controlling the shape of the rising and falling edges of AC output voltage pulses of a PWM frequency converter by reducing a speed of change of, and a height of, the AC output voltage pulses, in which the PWM frequency converter is a network bridge for rectifying an alternating voltage of a supply network into a DC voltage (UDC) of a DC intermediate circuit, which is filtered with a filtering capacitor (CDC), a load bridge comprised of phase switches implemented with power semiconductor components, which forms an AC output voltage (U, V, W) from the DC voltage of the intermediate circuit for controlling the load (M), and a control unit,
comprising one of said phase switches for setting an average speed of voltage change of the AC output voltage pulses of at least one power component to control the at least one power component to be conductive and non-conductive in turn for a period of at least about one microsecond to change a pulse edge of the AC output voltage pulses into at least one micropulse, and wherein the width of the at least one micropulse is controlled to increase towards a final state of said phase switch.
Specification