| 摘要 |
<p>At times, it may be necessary to operate switches of a PWM inverter to provide a low output voltage. However, in order to produce such a low voltage, it may be necessary to operate the switches near their minimum on time limit, which can in turn lead to damage or destruction of the switches. In order to overcome this problem, a control (20) for an inverter (18) which produces an output voltage having two levels wherein the inverter (18) includes first and second switches (Q1, Q2) coupled to an inverter output (30A) produces first and second switch control signals each having alternating switch on and switch off portions wherein each switch on portion is of a duration in excess of the minimum on time limit of the switches (Q1, Q2). The first and second switches (Q1, Q2) are operated in accordance with the first and second switch control signals, respectively, to produce the output voltage wherein the switches are operated in a particular switch state for a duration less than the minimum on time limit of the switches to cause the output voltage to assume one of the levels during such time. Inasmuch as the switches are operated for periods of time in excess of the minimum on time limit, the risk of damage to or destruction of the switches is minimized.</p> |
