Five pulse transformer iron core material requirements
Pulse transformer core 2019 - five material requirements 03 - 30 15:05:21 pulse transformer is used to transmit pulse transformer. When a series of pulse duration of td ( ms) Voltage, pulse amplitude of Um ( V) Single pulse voltage is added to the number of turns for N pulse transformer winding, at the end of each pulse, the magnetic induction intensity increment & Delta; B( T) To: & Delta; B=Umtd/NSc′ 10 - 2 which Sc is the cross-sectional area of iron core ( cm2） 。 The magnetic induction intensity increment & Delta; And the area of the pulse voltage (B Volt-second product) Is proportional to the. When the output one-way pulse, & Delta; B = Bm - Br, if add the demagnetization winding on pulse transformer core, & Delta; B=Bm+Br。 Under pulse condition, by the dynamic pulse hysteresis loop & Delta; B with the corresponding & Delta; The ratio of the Hp for pulse magnetic permeability mp. The ideal pulse waveform is refers to the rectangular pulse wave, because of the influence of the parameters of the circuit, the actual pulse waveform with rectangular pulse, often the distortion. Such as the rise time of pulse edge of tr and pulse transformer leakage inductance Ls, winding and structural parts caused by distributed capacitance is proportional to the Cs, pulse roof fall l is inversely proportional to the excitation inductance Lm, eddy current loss factor also affects the pulse waveform of the output. Pulse transformer leakage inductance Ls = 4 bpn12lm/h pulse transformer primary excitation inductance Lm = 4 mppscn2 / l′ 10 - 9 eddy current loss = Umd2tdlF Pe / 12 n12scr b related to winding structure coefficient, lm for the average winding coil turns long, h is the width of the windings, N1 for primary winding circle number, l as the core of the average length of magnetic circuit, cross section area of Sc as the core, mp for core pulse magnetic conductivity, resistivity of r as core material, d is the thickness of the core material, for the pulse repetition frequency F. Can be seen from the above formula, in a given number of turns and core area, the greater the pulse width, requirement of core material variation of magnetic induction intensity & Delta; The larger the B; In pulse width to timing, improve the magnetic induction intensity change of the core material & Delta; B, can greatly reduce the pulse transformer iron core of cross-sectional area and the number of turns of the magnetizing winding, can reduce the volume of the pulse transformer. To reduce the pulse wave front distortion, we should try to reduce the pulse transformer leakage inductance and distributed capacitance, therefore need to make the pulse transformer winding circle number as less as possible, which requires the use of high pulse magnetic permeability of materials. To reduce the top down, as far as possible to improve primary excitation inductance Lm, which requires the core material has high pulse magnetic permeability mp. To reduce the eddy current loss, should choose high resistivity and thickness of thin soft magnetic strip as core material as far as possible, especially for high repetition frequency, pulse width of pulse transformer. Pulse transformer iron core material requirements as follows: high saturation magnetic induction intensity of Bs value; The pulse with high magnetic permeability, with small size core excitation inductance to obtain large enough; High power single polarity pulse transformer requirements with large magnetic induction intensity increment & Delta; B, using low remanence materials; When additional dc bias is used for core high rectangle ratio, small coercive force Hc. Low power pulse transformer required core of initial pulse high magnetic permeability; Low dissipation factor.