Time division multiplexing multi-level circuit and insulation impedance detection method

[0034] see Figure 4 , Figure 4 It is the circuit diagram of the second embodiment of the time-division multiplexed multi-level circuit of the present invention; this embodiment discloses a time-division multiplexed multi-level circuit, including 2n+5 switch tubes, 2n+4 impedance networks, Detection and control unit; the 2n+5 switching tubes are respectively: the first switching tube T0, the second switching tube T1...the 2n+4th switching tube T2n+3, the 2n+5th switching tube T2n+4; the The 2n+4 impedance networks are: the first impedance network Z1, the second impedance network Z2, ..., the 2n+3th impedance network Z2n+3, the 2n+4th impedance network Z2n+4, the first switching tube T1 and the th One impedance network Z1 is connected in parallel, the second switch tube T2 is connected in parallel with the second impedance network Z2, and so on, the 2n+4 switch tube T2n+3 is connected in parallel with the 2n+3 impedance network Z2n+3, and the 2n+5 switch tube T2n+4 and the 2n+4

[0038] In this embodiment, on the basis of Embodiment 1, n is zero, and the five switching tubes are: the first switching tube T0, the second switching tube T1, the third switching tube T2, the fourth switching tube T3 and the fifth switching tube. The switching tube T4; the four impedance networks are respectively: the first impedance network Z1, the second impedance network Z2, the third impedance network Z3, and the fourth impedance network Z4; the second switching tube T1 and the first impedance network The network Z1 is connected in parallel, the third switching tube T2 is connected in parallel with the second impedance network Z2, the fourth switching tube T3 is connected in parallel with the third impedance network Z3, and the fifth switching tube T4 is connected in parallel with the fourth switching tube T4. The impedance network Z4 is connected in parallel, one end of the second switching tube T1 is connected to the positive bus, the other end of the second switching tube

[0040] This embodiment discloses a method for detecting insulation resistance of a time-division multiplexed multi-level circuit, which includes the following steps:

[0041] The detection and control unit calculates and obtains at least two groups of positive and negative busbar-to-ground impedance values ​​according to the voltage change of the positive and negative busbars to ground detected when the state of the switching tube is switched;

[0042] The said "the detection and control unit calculates and obtains at least two groups of positive and negative busbar-to-ground impedance values ​​according to the voltage change of the positive and negative busbars to ground detected when the switching tube is switched" specifically: the said detection and control unit By switching the state of the second switching tube T1 and the first switching tube T0, and cooperating with the first impedance network Z1, the second impedance network Z2, the third impedance network Z3 and the fourt