Differential Modulation Fixed Frequency Excitation Generator Voltage Regulator with Preset Bidirectional Narrow Pulse

Abstract

A preset bidirectional narrow pulse differential modulation fixed-frequency excitation generator voltage regulator comprises a sampling unit 1000, a reference unit 1001, a comparison unit 1002, a narrow pulse generation unit 1003, a coupling capacitor C0, a power unit 1004 and a freewheeling unit 1005; the reference unit 1001 outputs a reference voltage to a first input end of the comparison unit1002, an output end of the sampling unit 1000 is connected with a second input end of the comparison unit 1002, the narrow pulse generation unit 1003 is connected with the second input end of the comparison unit 1002 through the coupling capacitor C0, an output end of the comparison unit 1002 is connected with an input end of the power unit 1004, the freewheeling unit 1005 is connected with an output end of the power unit 1004 and a positive pole of a power supply, a negative pole of the power unit 1005 is earthed, and the output end of the freewheeling unit 1005 controls a field current. Thepreset bidirectional narrow pulse differential modulation fixed frequency excitation generator voltage regulator is fixed in frequency, simple in structure, low in cost and high in reliability.

Description

technical field [0001] The invention belongs to the technical field of automobile generator control, and relates to a differential modulation fixed-frequency excitation generator voltage regulator with preset bidirectional narrow pulses. Background technique [0002] The current automobile generator will automatically adjust the excitation duty ratio according to the output voltage of the generator during the operation of the vehicle. The excitation adjustment method of the generator voltage regulator can be divided into: [0003] ① Completely non-fixed frequency excitation: The voltage regulator compares the effective equivalent of the output voltage with the set value, and determines whether to turn on the excitation or cut off the excitation based on the comparison result. Therefore, the excitation state is only determined by the output voltage, and the excitation frequency is determined by the effective output voltage. The calculation method of the equivalent, the respon...

AI Technical Summary

Problems solved by technology

[0003] ① Completely non-fixed frequency excitation: The voltage regulator compares the effective equivalent of the output voltage with the set value, and determines whether to turn on the excitation or cut off the excitation based on the comparison result. Therefore, the excitation state is only determined by the output voltage, and the excitation frequency is determined by the effective output voltage. The calculation method of the equivalent, the response time of the circuit, etc., the change of the load of the generator, the connection relationship of the battery, etc. can all affect the excitation frequency. When the battery is thrown with a load of 40A, the excitation frequency rises to 1.8KHz. The higher frequency increases the loss and heat generation of the power tube of the regulator, and also increases the iron loss of the generator. The instability of the excitation frequency causes the electromagnetic resistance of the generator to change. Larger, causing greater stress loss to the generator belt

[0004] ② Non-fixed frequency excitation triggered by fixed frequency: There is an oscillation circuit in the voltage regulator to trigger the excitation at a fixed frequency. When the output voltage of the generator exceeds the set value, the regulator cuts off the excitation. Although the excitation is triggered at a fixed frequency However, the excitation control terminal exhibits non-fixed frequency excitation, but the time difference of each time the excitation is turned on is an integer multiple of the same base. This kind of excitation control cannot detect the fixed frequency trigger pulse. Very similarly, its fixed-frequency trigger pulses are completely "blanked" during generator overvoltage

[0006] Existing control methods of fixed-frequency excitation voltage regulators include: triangular wave comparison type, which compares the output signal after sampling the output voltage of the generator with a constant-frequency equal-amplitude triangular wave to obtain a duty ratio modulation signal to control the excitation. This method is more common, but the triangular wave forming circuit is relatively complicated, and the requirements for the equal amplitude of the triangular wave are relatively high, because its amplitude is already used as a "benchmark" for comparison with the sampling signal, and it is mostly completed by a relatively complex digital-analog hybrid integrated chip. The circuit structure is complex and the cost is high

[0007] Chopper type, which uses a fixed-frequency trigger pulse to trigger the excitation, and cuts off the excitation when the voltage is overvoltage. It is mostly completed by a relatively complex digital-analog hybrid integrated chip, and the circuit structure is complex and the cost is high.

[0008] The above two methods can also be completed by single-chip microcomputers, but general-purpose single-chip microcomputers are often prone to failures in the power supply environment of generators with high temperature changes, high electromagnetic interference, and high surge impacts, such as various program problems, poor temperature resistance, etc. ; while high temperature resistant, high voltage resistant, single-chip microcomputer dedicated to generators is more expensive

Images