Apparatus and method for detecting phase currents of inverter
First Claim
1. An apparatus for detecting phase currents of an inverter, comprising:
- a switch section for converting a direct current power into an alternating current power and providing the alternating current power to a load as a plurality of upper switching elements and lower switching elements are turned-on according to a plurality of pulse width modulation signals;
a plurality of current detecting resistors coupled between the plurality of lower switching elements and a ground, respectively;
a plurality of analog/digital converters for converting voltages of the plurality of current detecting resistors into digital signals;
a triangular wave generator for generating a triangular wave having a predetermined time period;
a current detection controller for generating three-phase sine wave voltages, for comparing the generated three-phase sine wave voltage with a reference threshold voltage, and for varying the three-phase sine wave voltage according to the compared result to control a detection of the phase currents;
a pulse width modulation signal generator for comparing the three-phase sine wave voltages from the current detection controller with a voltage of the triangular wave generated by the triangular wave generator to generate and output the plurality of pulse width modulation signals to the switch section; and
a phase current detector for detecting output signals of the plurality of analog/digital converters as the phase currents according to a control of the current detection controller.
1 Assignment
0 Petitions
Accused Products
Abstract
The present invention previously sets a threshold voltage, compares the set threshold voltage with a reference voltage, and judges whether a minimal pulse width of a PWM signal is obtained. When a pulse width of one PWM signal is equal to or greater than the minimal pulse width, but each pulse width of two PWM signals is less than the minimal pulse width, a sine wave voltage corresponding to one of the two PWM signals less than the minimal pulse width is varied to a threshold voltage to detect two phase currents, and a remaining one phase current is calculated based on the two detected phase currents. After the phase current was detected by varying the threshold voltage, a level difference between an original sine wave voltage and the threshold voltage is set as a compensation voltage, and the sine wave voltage is compensated by the compensation voltage.
-
Citations
13 Claims
-
1. An apparatus for detecting phase currents of an inverter, comprising:
-
a switch section for converting a direct current power into an alternating current power and providing the alternating current power to a load as a plurality of upper switching elements and lower switching elements are turned-on according to a plurality of pulse width modulation signals; a plurality of current detecting resistors coupled between the plurality of lower switching elements and a ground, respectively; a plurality of analog/digital converters for converting voltages of the plurality of current detecting resistors into digital signals; a triangular wave generator for generating a triangular wave having a predetermined time period; a current detection controller for generating three-phase sine wave voltages, for comparing the generated three-phase sine wave voltage with a reference threshold voltage, and for varying the three-phase sine wave voltage according to the compared result to control a detection of the phase currents; a pulse width modulation signal generator for comparing the three-phase sine wave voltages from the current detection controller with a voltage of the triangular wave generated by the triangular wave generator to generate and output the plurality of pulse width modulation signals to the switch section; and a phase current detector for detecting output signals of the plurality of analog/digital converters as the phase currents according to a control of the current detection controller. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9)
-
-
10. A method for detecting phase currents of an inverter, comprising:
-
(i) generating three-phase sine wave voltages in response to a command signal; (ii) comparing the three-phase sine wave voltages with a reference threshold voltage, respectively; (iii) varying one of two three-phase sine wave voltages among the three-phase sine wave voltages being greater than the threshold voltage into the threshold voltage when one of the three-phase sine wave voltages is equal to or less than the threshold voltage as the comparison result; and (iv) detecting a current of a phase corresponding to the sine wave voltage varied to the threshold voltage and a current of a phase corresponding to a sine wave voltage being less than or equal to the threshold voltage, and calculating a remaining one phase current based on the two detected phase currents. - View Dependent Claims (11, 12, 13)
-
Specification