Detection method of real-time voltage vectors in energy feedback unit

[0026] The present invention will be further described below in conjunction with the drawings.

[0027] Such as Figure 2~4 As shown, the real-time voltage vector detection method in the energy feedback unit includes

[0028] 1) Sampling the three-phase AC voltage U of the grid abc;

[0029] 2) To U abc Carry out CLARK transformation to get U in the two-phase stationary coordinate system αβ;

[0030] 3) To U αβ Carry out the PARK transformation of the positive initial θ angle to obtain the positive sequence voltage work component U in the rotating coordinate system d +, positive sequence reactive component U q +, at the same time U αβ Perform the PARK transformation of the negative initial θ angle to obtain the negative sequence voltage work component U in the rotating coordinate system d -, negative sequence reactive component U q -;

[0031] 4) Respectively to U d +, U q +, U d -, U q -Perform a notch of twice the initial ω to remove the AC quantity of the positive and negative sequence components, and then U d `+, U q `+, U d `-, U q `-;

[0032] 5) The initial positive sequence voltage power component, initial positive sequence reactive component, initial negative sequence voltage power component, initial negative sequence reactive power component, and initial angle θ are used as decoupling parameters. d `+, U q `+, U d `-, U q `- Decoupling, get U d *+, U q *+, U d *-, U q *-;

[0033] 6) To U d *+, U q *+, U d *-, U q *-The target positive sequence voltage power component U is obtained after first-order filtering d ^+, target positive sequence reactive component U q ^+, target negative sequence voltage power component U d ^-and the target negative sequence reactive component U q ^-, where the target positive sequence voltage work component U d ^+ is the required voltage amplitude, and the target positive sequence voltage work component U d ^+, target positive sequence reactive component U q ^+, target negative sequence voltage power component U d ^-and the target negative sequence reactive component U q ^-As the initial positive sequence voltage power component, initial positive sequence reactive power component, initial negative sequence voltage power component, and initial negative sequence reactive power component of the next detection cycle;

[0034] 7) To U q *+ Perform PI adjustment control to make U q Control at 0, and the result obtained is the frequency of the three-phase power supply, which is used as the initial ω of the next detection cycle;

[0035] 8) Integrate the frequency of the three-phase power supply to obtain the real-time θ angle of the three-phase power supply, which is used as the initial θ angle of the next detection cycle.

[0036] The present invention is implemented in a 100 microsecond PWM control circuit.

[0037] Such as Figure 4 The present invention is carried out in a 32Bit DSP12, its operating frequency is 100MHz, and the real-time detection values ​​of the DC detection unit 11, the AC voltage detection unit 10, and the current detection unit 9 are used as input. The present invention uses the detected AC voltage As the core, external interference signals (including negative sequence harmonics, etc.) are removed through its detection and DSP calculations to obtain the actual positive sequence voltage and its phase. When all the processing is completed, the DSP will send a signal to the IGBT driving circuit 13 for driving the GBTI circuit 5. The IGBT circuit 5 is a power switch conversion device, used to chop the DC voltage into a PWM wave. The inductor 6 filters out the PWM carrier to obtain a sinusoidal voltage so that it can be connected to the power grid. There is a fast melting between the AC380 AC power grid 8 and the inductor 6 Silk 7 is used to protect the device. In the DC circuit, there are DC540V DC power supply circuit 1 and fast fuse 2 2, fast fuse 3 3 used for the protection device, and the capacitor 4 is used for energy storage and buffering purposes, and is used to store a part of the electric energy from the DC circuit.