Single-stage bidirectional DC converter and single-phase user-side energy storage inverter based on single-stage bidirectional DC converter

A single-phase user-side energy storage inverter based on a single-stage bidirectional DC converter, comprising a single-stage bidirectional DC and an inverter circuit connected to the single-stage bidirectional DC converter,

• wherein the single-stage bidirectional DC converter is used for bidirectional charge and discharge of a battery, and comprises a transformer T1, a bus-side circuit, a battery-side circuit and a controller, wherein the bus-side circuit is electrically connected to a primary side of the transformer T1, and the battery-side circuit is electrically connected to a secondary side of the transformer T1;
• the bus-side circuit comprises at least one energy storage branch, each said energy storage branch comprises a bus-side switching transistor, the battery-side circuit comprises a battery-side switching transistor, the controller is used for controlling on/off of the bus-side switching transistor and the battery-side switching transistor, and the battery-side switching transistor and the bus-side switching transistor are turned on and off complementarily,
• wherein the bus-side circuit of the single-stage bidirectional DC converter comprises two energy storage branches, and the two energy storage branches are respectively connected to a positive terminal VBUS+ of the DC bus and a negative terminal VBUS− of the DC bus;
• each said energy storage branch comprises a bus-side switching transistor, the battery-side circuit comprises a battery-side switching transistor, the controller is used for controlling on/off of the bus-side switching transistors and the battery-side switching transistor, the bus-side switching transistors are turned on and off synchronously, and the battery-side switching transistor and the bus-side switching transistors are turned on and off complementarily,
• wherein the two energy storage branches are a first energy storage branch and a second energy storage branch respectively, the first energy storage branch and the second energy storage branch are respectively connected to the dotted terminal and the undotted terminal of the primary winding of the transformer T1, and a center tap of the primary winding of the transformer T1 is grounded;
• the first energy storage branch comprises an inductor L1_A, a third capacitor C3 and a first switching transistor Q1, and the second energy storage branch comprises an inductor L1_B, a fourth capacitor C4 and a second switching transistor Q2;
• the inductor L1_A and the third capacitor C3 are connected in series and then connected between the dotted terminal of the primary winding of the transformer T1 and the positive terminal VBUS+ of the DC bus, a drain of the first switching transistor Q1 is connected to a midpoint between the inductor L1_A and the third capacitor C3, and a source of the first switching transistor Q1 is connected to the center tap of the primary winding of the transformer T1 and is grounded;
• the inductor L1_B and the fourth capacitor C4 are connected in series and then connected between the undotted terminal of the secondary winding of the transformer T1 and the negative terminal VBUS− of the DC bus, a source of the second switching transistor Q2 is connected to a midpoint between the inductor L1_B and the fourth capacitor C4, and a drain of the second switching transistor Q2 is connected to the center tap of the primary winding of the transformer T1 and is grounded;
• a first capacitor C1 and a second capacitor C2 are respectively connected between the positive terminal VBUS+ of the DC bus and the center tap of the primary winding of the transformer T1 as well as between the negative terminal VBUS− of the DC bus and the center tap of the primary winding of the transformer T1.