CN105356419A - Improved artillery alternating-current servo system motor current overload protection method - Google Patents

Abstract

The invention provides an improved artillery alternating-current servo system motor current overload protection method. An overload determining expression and an overload threshold are designed according to the heating condition. When a servo system works, if the output current of the motor exceeds the rated current to a certain extent due to too high load resistance or other factors, a motor current overload protection signal is output to indicate the alarm of the servo system or make the servo system stop working. Therefore, the risk of motor damage due to long-term current overload is effectively avoided.

Description

A kind of modified model cannon exchanges the guard method of servomechanism motor current overload

Technical field

The present invention relates to fire zone open, particularly relate to the protecting control that cannon exchanges servomechanism.

Background technology

Exchange servomechanism to be widely used in the armament systems such as antiaircraft gun, seismic bombing, rocket gun, along with the development of power electronic technology and computer technology, the actuating motor exchanging servomechanism extensively adopts permagnetic synchronous motor, is made up of on controlling electric current loop, speed ring and position ring.In servomechanism start-up course or overcome in the process of load resistance, under the motor of servomechanism is often operated in the pattern of current overload, namely exceeded the rated current of motor, transshipping for the short time motor is allow, but current overload exceedes certain limit, as long term overloading, will the loss of expanded motor, even motor damage, causes irreversible consequence, therefore, the restriction of certain condition must be carried out to the current overload of motor.

In Chinese patent " a kind of cannon exchanges servomechanism the overload protection method " (patent No.: 201318001239.7); invent a kind of current overload protection maintaining method; give the condition that current overload exceedes certain thresholding, but its threshold value is not chosen by equivalence heating during overload.

Summary of the invention

In order to overcome the deficiencies in the prior art, the invention provides a kind of modified model cannon and exchanging the guard method of servomechanism motor current overload, according to heating condition, overload predicated expressions and overload threshold being designed, realizing motor current overload protection.

The technical solution adopted for the present invention to solve the technical problems comprises the following steps:

The first step, setting sustained overload initial value u (k-1)=0;

Second step, gathers the motor threephase stator current i of current time k _a(k), i _b(k), i _c(k), or gather any biphase current and pass through i _a(k)+i _b(k)+i _ck ()=0 calculates the electric current of third phase;

3rd step, calculates the current effective value of motor

4th step, calculate motor current overload decision condition, step is as follows:

Ith step, calculates sustained overload expression formula wherein, I _ratedfor Rated motor line current, I _ratedfor the specified line current of motor, T _sfor the sampling period;

IIth step, if u (k) < 0, then makes u (k)=0;

IIIth step, if then to system output current overload protection signal, wherein, α is motor current overload multiple, T _αfor the motor current overload time;

IVth step, makes u (k-1)=u (k), returns second step.

Described motor current overload multiple and the span of motor current overload time are 1.5≤α≤5, (α-1) ²t _α≤ 50s, sampling period T _s≤ 50ms.

The invention has the beneficial effects as follows: when servomechanism works; motor output current is caused to exceed rated current to a certain degree if run into the factors such as load resistance is excessive; will output motor overcurrent protection signal; alarm for servomechanism indicates; or servomechanism is quit work, effectively can avoid the risk because of long-time current overload damage motor.

Embodiment

Below in conjunction with embodiment, the present invention is further described, the present invention includes but be not limited only to following embodiment.

The invention discloses a kind of cannon and exchange servomechanism motor current overload protection implementation method, if the specified line current of motor is I _rated, motor current overload multiple is α, and the motor current overload time is T _α, α and T _αspan is 1.5≤α≤5, (α-1) ²t _α≤ 50s, the sampling period is T _s(T _s≤ 50ms), fire zone open motor current overload protection specific implementation step is:

The first step: setting sustained overload initial value u (k-1)=0;

Second step: gather current time (k moment) motor threephase stator current i _a(k), i _b(k), i _c(k), or gather any biphase current and pass through i _a(k)+i _b(k)+i _ck ()=0 calculates the electric current of third phase.

3rd step: the current effective value calculating motor

$I_{rms}\left(k\right)=\sqrt{\frac{i_A^2\left(k\right)+i_B^2\left(k\right)+i_C^2\left(k\right)}{3}}$

4th step: calculate motor current overload decision condition, this step divides four little steps to realize:

Ith step: calculate sustained overload expression formula

$u\left(k\right)=u(k-1)+\&lsqb;I_{rms}^2\left(k\right)-I_{rated}^2\&rsqb;T_s$

Wherein, I _ratedfor Rated motor line current (effective value).

IIth step: if u (k) < 0, then make

u(k)＝(

IIIth step: if then to system output current overload protection signal;

IVth step: make u (k-1)=u (k), return second step.

Embodiment 1:

If the specified line current I of motor _rated=10A (effective value), motor current overload multiple α=1.5, motor current overload time T _α=40s, sampling period T _s=5ms, then fire zone open motor current overload protection specific implementation step is:

The first step: setting sustained overload initial value u (k-1)=0;

Second step: gather current time (k moment) motor threephase stator current i _a(k), i _b(k), i _c(k), or gather any biphase current and pass through i _a(k)+i _b(k)+i _ck ()=0 calculates the electric current of third phase.

3rd step: the current effective value calculating motor

$I_{rms}\left(k\right)=\sqrt{\frac{i_A^2\left(k\right)+i_B^2\left(k\right)+i_C^2\left(k\right)}{3}}$

4th step: calculate motor current overload decision condition, this step divides four little steps to realize:

Ith step: calculate sustained overload expression formula

$u\left(k\right)=u(k-1)+\&lsqb;I_{rms}^2\left(k\right)-100\&rsqb;\&times;0.005$

IIth step: if u (k) < 0, then make

u(k)＝(

IIIth step: if then to system output current overload protection signal;

IVth step: make u (k-1)=u (k), return second step.

Embodiment 2:

If the specified line current I of motor _rated=10A (effective value), motor current overload multiple α=5, motor current overload time T _α=2.083s, sampling period T _s=5ms, then fire zone open motor current overload protection specific implementation step is:

The first step: setting sustained overload initial value u (k-1)=0;

Second step: gather current time (k moment) motor threephase stator current i _a(k), i _b(k), i _c(k), or gather any biphase current and pass through i _a(k)+i _b(k)+i _ck ()=0 calculates the electric current of third phase.

3rd step: the current effective value calculating motor

$I_{rms}\left(k\right)=\sqrt{\frac{i_A^2\left(k\right)+i_B^2\left(k\right)+i_C^2\left(k\right)}{3}}$

4th step: calculate motor current overload decision condition, this step divides four little steps to realize:

Ith step: calculate sustained overload expression formula

$u\left(k\right)=u(k-1)+\&lsqb;I_{rms}^2\left(k\right)-100\&rsqb;\&times;0.005$

IIth step: if u (k) < 0, then make

u(k)＝(

IIIth step: if then to system output current overload protection signal;

IVth step: make u (k-1)=u (k), return second step.

Claims (2)

1. modified model cannon exchanges the guard method of servomechanism motor current overload, it is characterized in that comprising the steps:

The first step, setting sustained overload initial value u (k-1)=0;

Second step, gathers the motor threephase stator current i of current time k _a(k), i _b(k), i _c(k), or gather any biphase current and pass through i _a(k)+i _b(k)+i _ck ()=0 calculates the electric current of third phase;

3rd step, calculates the current effective value of motor

4th step, calculate motor current overload decision condition, step is as follows:

Ith step, calculates sustained overload expression formula wherein, I _ratedfor Rated motor line current, I _ratedfor the specified line current of motor, T _sfor the sampling period;

IIth step, if u (k) < 0, then makes u (k)=0;

IIIth step, if then to system output current overload protection signal, wherein, α is motor current overload multiple, T _αfor the motor current overload time;

IVth step, makes u (k-1)=u (k), returns second step.

2. modified model cannon according to claim 1 exchanges the guard method of servomechanism motor current overload, it is characterized in that: described motor current overload multiple and the span of motor current overload time are 1.5≤α≤5, (α-1) ²t _α≤ 50s, sampling period T _s≤ 50ms.