Electric power conversion apparatus

Abstract

A single-phase AC/DC electric power conversion apparatus includes an indirect matrix converter having an input interface to receive a first alternating current (AC) signal and an output interface to produce a second AC signal, where the first AC signal has a grid frequency. A transformer has a primary winding and an electrically isolated and magnetically coupled secondary winding. A coupling inductor is connected in series between the output interface of the indirect matrix converter and the primary winding. An H-bridge switching arrangement is connected to the secondary winding and produces an output signal having a DC component and at least one AC component. The at least one AC component has a second order harmonic of the grid frequency. An active filter reduces the second order harmonic AC component. A modular conversion apparatus for three-phase power replicates the single-phase apparatus as a module for each phase and omits the active filter.

1 .- 14 . (canceled) 
     
     
         15 . An electric power conversion apparatus, comprising:
 an matrix converter having an input interface configured to receive a first alternating current (AC) signal and an output interface configured to produce a second AC signal, said matrix converter having a plurality of bi-directional switches, said first AC signal having a first frequency;   a transformer having a primary winding and an electrically isolated and magnetically coupled secondary winding;   a coupling inductor coupled in series between said output interface of said indirect matrix converter and said primary winding;   an H-bridge switching arrangement connected to said secondary winding and configured to produce an output signal on an output node, said output signal having a DC component and at least one AC component wherein said at least one AC component comprises a second harmonic of said first frequency; and   an active filter coupled to said output node and configured to reduce said second harmonic AC component.   
     
     
         16 . An apparatus for converting a multi-phase AC signal to a DC signal, comprising:
 a plurality of single-phase AC/DC conversion modules each comprising:
 an indirect matrix converter having an input interface configured to receive a respective one of said phases of said AC signal and an output interface configured to produce a second AC signal, said respective one of said phases of said AC signal having a first frequency; 
 a transformer having a primary winding and an electrically isolated and magnetically coupled secondary winding; 
 a coupling inductor coupled in series between said output interface of said indirect matrix converter and said primary winding; 
 an H-bridge switching arrangement connected to said secondary winding and configured to produce a respective output signal on an output node, said respective output signal having a DC component and at least one AC component wherein said at least one AC component comprises a second order harmonic of said first frequency in phase; 
   where each of said phases of said multi-phase AC signal being offset from the remaining ones of said plurality of phases, and wherein respective output signals from said plurality of single-phase modules are electrically joined at said output node, wherein respective second order harmonics associated with said respective output signals tend to cancel each other out.   
     
     
         17 . The apparatus of  claim 16  further comprising an output capacitor electrically connected between said output node and a ground node. 
     
     
         18 . The apparatus of  claim 17  further comprising an output inductor coupled between said output node and a load. 
     
     
         19 . The apparatus of  claim 15  further comprising:
 an electronic controller including a processor and a memory, said electronic controller being communication with said matrix converter and said H-bridge switching arrangement, said electronic controller including main control logic stored in said memory, said main control logic when executed by said processor is configured to control operation of said matrix converter and said H-bridge switching arrangement to achieve power factor correction (PFC) and zero voltage switching (ZVS). 
 
     
     
         20 . The apparatus of  claim 19  wherein said matrix converter comprises a rectifier responsive to said first AC signal configured to produce a first direct current (DC) signal, said rectifier including a plurality of rectifier switches arranged in a full bridge arrangement; and
 wherein said electronic controller includes rectifier logic stored in said memory, said rectifier logic when executed by said processor is configured to generate a first set of switch control signals corresponding to gate drive signals for said plurality of rectifier switches. 
 
     
     
         21 . The apparatus of  claim 20  further comprising a grid voltage sensor in sensing relation to an AC power source outputting a grid power signal and configured to generate a grid voltage signal indicate of said grid voltage. 
     
     
         22 . The apparatus of  claim 21  wherein said rectifier logic is responsive to said grid voltage signal in generating said first set of switch control signals. 
     
     
         23 . The apparatus of  claim 20  wherein said matrix converter further comprises a DC to AC converter coupled to said rectifier and configured to convert said first DC signal into said second AC signal, said second AC signal having a second frequency that is greater than said first frequency, said DC to AC converter including a plurality of DC to AC switches including said bi-directional switches, wherein said main control logic when executed by said processor of said electronic controller is configured to generate a second set of switch control signals corresponding to gate drive signals for said DC to AC switches. 
     
     
         24 . The apparatus of  claim 23  wherein said H-bridge switching arrangement includes a plurality of H-bridge switches arranged in an H-bridge configuration, said main control logic when executed by said processor of said electronic controller is configured to generate a third set of switch control signals corresponding to gate drive signals for said H-bridge switches. 
     
     
         25 . The apparatus of  claim 24  wherein said main control logic includes power factor correction (PFC) logic which, when executed by said processor of said electronic controller, is configured to generate said second and third sets of switch control signals to increase a power factor associated with power drawn from said AC source toward one. 
     
     
         26 . The apparatus of  claim 25  wherein said PFC logic is configured to vary a phase difference in gate drive signals associated with respective H-bridge switches. 
     
     
         27 . The apparatus of  claim 15  wherein current through said coupling inductor is bi-directional. 
     
     
         28 . The apparatus of  claim 15  further comprising an output capacitor coupled between said output node and a ground node. 
     
     
         29 . The apparatus of  claim 19  wherein said active filter is one selected from the group comprising a boost type active filter, a buck type active filter, and an H-bridge type active filter. 
     
     
         30 . The apparatus of  claim 29  wherein said active filter comprises said boost type active filter, said boost type active filter comprises:
 a filter inductor having a first end and a second end wherein said first end is connected to said output node; 
 a first filter switch having a first drain connected to said second end of said filter inductor, a first source connected to a ground node, and a first gate; 
 a filter capacitor having a first end and a second end connected to said ground node; and 
 a second filter switch having a second drain connected to said first end of said filter capacitor, a second source connected to said end of said inductor, and a second gate. 
 
     
     
         31 . The apparatus of  claim 30  wherein said controller is connected to said first and second gates of said first and second filter switches, said main control logic includes active filter duty cycle control logic which when executed by said processor is configured to generate a fourth set of switch control signals corresponding to gate drive signals for said first and second filter switches, said duty cycle control logic is configured to reduce said second harmonic by selectively activating said first and second filter switches to store and release energy in said filter inductor. 
     
     
         32 . The apparatus of  claim 16  wherein each of said plurality of indirect matrix converters comprise (i) a rectifier responsive to said first AC signal configured to produce a first direct current (DC) signal, said rectifier including a plurality of rectifier switches responsive to a first set of switch control signals, and (ii) a DC to AC converter coupled to said rectifier and configured to convert said first DC signal into said second AC signal and having a plurality of DC to AC switches responsive to a second set of switch control signals; and
 wherein said H-bridge switching arrangement includes a plurality of H-bridge switches responsive to a third set of switch control signals, and 
 further comprising an electronic controller including a processor and a memory, said electronic controller being in communication with each of said indirect matrix converters and each of said H-bridge switching arrangements, said electronic controller having main control logic including power factor correction (PFC) logic stored in said memory which, when executed by said processor, is configured to generate, for each of said indirect matrix converter, respective second and third sets of switch control signals to increase a power factor associated with power drawn from said AC source towards one.