Voltage converter systems

Abstract

A voltage converter system includes a first DC-AC voltage converter that converts a first DC voltage signal to a first AC voltage signal. A DC link converts the first AC voltage signal to a second DC voltage signal. A second DC-AC voltage converter converts the second DC voltage signal to a second AC voltage signal. In another configuration a DC-AC voltage converter converts a DC voltage signal to a first AC voltage signal. An AC-AC voltage converter converts the first AC voltage signal to a second, lower-frequency AC voltage signal. In yet another configuration a first voltage converter portion converts a DC voltage signal to pulses of DC voltage. A second voltage converter portion converts the pulses of DC voltage to a relatively low-frequency AC voltage signal. The voltage converter system is selectably configurable as a DC-AC voltage converter or an AC-DC voltage converter.

What is claimed is: 
     
         1 . A voltage converter system, comprising:
 a first, high-frequency, DC-AC voltage converter configured to receive a first DC voltage signal and generate a first AC voltage signal;   a DC link configured to receive the first AC voltage signal and convert the first AC voltage signal to a second DC voltage signal; and   a second DC-AC voltage converter configured to receive the second DC voltage signal and generate a second AC voltage signal.   
     
     
         2 . The voltage converter system of  claim 1 , further including an electrical filter configured to limit electromagnetic interference generated by the second AC voltage signal. 
     
     
         3 . A voltage converter system, comprising:
 a DC-AC voltage converter configured to receive a DC voltage signal and generate a first, relatively high-frequency, AC voltage signal; and   an AC-AC voltage converter configured to receive the first AC voltage signal and generate a second AC voltage signal, a frequency of the second AC voltage signal being lower than the frequency of the first AC voltage signal.   
     
     
         4 . The voltage converter system of  claim 3 , further including an electrical filter configured to limit electromagnetic interference generated by the second AC voltage signal. 
     
     
         5 . The voltage converter system of  claim 3  wherein the DC-AC voltage converter includes a transformer having a relatively high turns ratio, the transformer further operating under regulation. 
     
     
         6 . A voltage converter system, comprising:
 a first voltage converter portion, configured to receive a DC voltage signal and convert the DC voltage signal to pulses of DC voltage; and   a second voltage converter portion, configured to receive the pulses of DC voltage and convert the pulses of DC voltage to an AC voltage signal.   
     
     
         7 . The voltage converter system of  claim 6  wherein the pulses of DC voltage are half-sinusoidal pulses. 
     
     
         8 . The voltage converter system of  claim 6  wherein the first voltage converter portion includes:
 a Ćuk-type voltage converter; and 
 a single-ended primary inductor converter (SEPIC) voltage converter, 
 the Ćuk-type voltage converter and the SEPIC voltage converter being electrically combined to operate cooperatively. 
 
     
     
         9 . The voltage converter system of  claim 8  wherein the pulses of DC voltage produced by the electrically combined Ćuk-type voltage converter and SEPIC voltage converter have an output voltage about twice the voltage available from each converter individually, each voltage converter providing about half of output power delivered by the voltage converter system. 
     
     
         10 . The voltage converter system of  claim 8  wherein a switch and an inductor are common to both the Ćuk-type voltage converter and the SEPIC voltage converter. 
     
     
         11 . The voltage converter system of  claim 8  wherein the first voltage converter portion includes an inductor/transformer. 
     
     
         12 . The voltage converter system of  claim 6  wherein the first voltage converter portion includes:
 a first and a second inductor connected in series, the first and second inductors each having an input and an output; 
 a first capacitor electrically intermediate the first and second inductors, a first terminal of the first capacitor being electrically connected to the output of the first inductor and a second terminal of the first capacitor being electrically connected to the input of the second inductor; 
 a third and a fourth inductor connected in series, the third and fourth inductors each having an input and an output; 
 a second capacitor electrically intermediate the third and fourth inductors, a first terminal of the second capacitor being electrically connected to the output of the third inductor and a second terminal of the second capacitor being electrically connected to the input of the fourth inductor; 
 a first switch coupled between the input of the first inductor and the output of the third inductor; 
 a second switch coupled between the output of the first inductor and the input of the third inductor; 
 a rectifier having an anode and a cathode, the anode of the rectifier being electrically connected to the second terminal of the first capacitor and the cathode of the rectifier being electrically coupled to the second terminal of the second capacitor; and 
 a third switch electrically connected in parallel with the rectifier, 
 the voltage converter system being configured to receive a DC voltage signal at the inputs of the first and third inductors and to generate an AC voltage signal at the outputs of the second and fourth inductors. 
 
     
     
         13 . The voltage converter system of  claim 12 , further including a third capacitor, the third capacitor being electrically intermediate the second and fourth inductors, a first terminal of the third capacitor being electrically connected to the output of the second inductor and a second terminal of the third capacitor being electrically connected to the output of the fourth inductor. 
     
     
         14 . The voltage converter system of  claim 12  wherein the switches switch synchronously. 
     
     
         15 . The voltage converter system of  claim 14  wherein the switches are semiconductors. 
     
     
         16 . The voltage converter system of  claim 12  wherein at least two inductors are magnetically coupled. 
     
     
         17 . The voltage converter system of  claim 6  wherein the voltage converter system is selectably configurable as a DC-AC voltage converter and an AC-DC voltage converter. 
     
     
         18 . The voltage converter system of  claim 6  wherein the second voltage converter portion further provides electrical isolation. 
     
     
         19 . The voltage converter system of  claim 6  wherein the AC voltage signal has a relatively low frequency. 
     
     
         20 . The voltage converter system of  claim 19  wherein the AC voltage signal has a voltage of about 120 VAC and a frequency of about 60 Hz.