A constant-frequency equal-energy control method for a micro-spark pulse power supply

Abstract

The invention discloses a constant-frequency equal-energy control method of a micro electric spark pulse power supply. According to a machining occasion and gap load characteristics, control parameters of the pulse power supply are set, and the pulse applying time and the deionizing time are determined; in the pulse applying stage, a gap voltage signal and a gap current signal are sampled, amplified correspondingly and summed, and closed-loop control is conducted on the sum result to enable the sum result to be consistent with a reference signal; after a gap is broken down, the current discharging stage is started, the corresponding breakdown time is recorded, the reference signal is updated according to the breakdown time, and closed-loop control is conducted on the sum result to enable the sum result to be consistent with the updated reference signal; and after current discharging, deionizing is conducted, and then the next machining period is conducted. According to the method, the sum of a gap voltage and a gap current is used as an only control variable for feeding back closed-loop control, and it is guaranteed that discharging energy is consistent every time while the voltage pulse frequency on the gap is kept constant.

Description

technical field [0001] The invention belongs to the field of high-frequency pulse power supply control for micro electric discharge machining, and in particular relates to a constant frequency and other energy control method of a micro electric discharge pulse power supply. Background technique [0002] EDM is a non-traditional machining technique that uses controlled electrical energy to form a spark discharge between an electrode and a tool to remove the material being machined. Existing pulse power supplies for EDM generally include non-independent pulse power supplies and independent pulse power supplies. The non-independent pulse power supply controls the maximum energy of a single discharge by adjusting the size of the discharge capacitor and the value of the charging voltage applied to it. When a small discharge capacitor and low charging voltage are used, the non-independent pulse power supply can provide extremely low discharge energy. It is still widely used in mi...

AI Technical Summary

Problems solved by technology

The former applies a pulse time T in the gap on and deionization time T off maintain a constant pulse voltage v p , its pulse voltage width and discharge frequency 1 / T s Fixed, similar to open-loop control, but due to the variable discharge gap in actual processing, the breakdown delay time is different, resulting in the real discharge time t on Not fixed, that is, the consistency of a single discharge energy is difficult to guarantee

The latter controls the discharge time T after the discharge gap breaks down on and deionization time T off Keep it fixed to realize the control of single discharge energy, and the discharge consistency is better, but this control strategy requires a detection circuit to identify the state of the discharge gap, and the breakdown time of the actual discharge gap is not fixed, so the actual discharge pulse v p The frequency of 1 / t s will keep changing

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