Method for controlling a turbomachine comprising an electric machine
The invention relates to a method for controlling a turbomachine comprising a gas generator, the turbomachine comprising an electric machine forming a device for injecting torque into/removing torque from one of the low pressure/high pressure rotation shafts of said gas generator. Said method comprises a step of implementing a fuel control loop in order to determine a fuel flow setpoint into the combustion chamber, and comprising, in the event that at least one operability limit is reached, determining a corrected fuel flow setpoint, said corrected fuel flow setpoint exhibiting a difference in relation to the setpoint. Said method also comprises a step of implementing a torque control loop in order to determine a torque setpoint for the electric machine, and comprising determining a torque correction quantity as a function of said difference, said torque setpoint being determined as a function of said torque correction quantity.
1. A method for controlling a turbomachine comprising a gas generator comprising a combustion chamber, a low-pressure rotation shaft and a high-pressure rotation shaft, the turbomachine comprising at least one electric machine forming a device for injecting torque into/removing torque from one of said rotation shafts, said method comprising a step of implementing a fuel control loop in order to determine a fuel flow setpoint into the combustion chamber, and comprising:
monitoring the turbomachine in order to detect if at least one operability limit of said turbomachine is reached,
if said at least one operability limit is reached, determining a corrected fuel flow setpoint, said corrected fuel flow setpoint exhibiting a difference, referred to as the “flow difference”, in relation to the current fuel flow setpoint,
said method also comprising a step of implementing a torque control loop in order to determine a torque setpoint for said at least one electric machine, and comprising determining a torque correction quantity as a function of said flow difference, said torque setpoint being determined as a function of said torque correction quantity wherein the torque correction quantity is determined to be equal to:
EC_DEB
×
FHV
×
η
C_
1
×
N
expression in which:
EC_DEB corresponds to the flow difference,
FHV corresponds to the calorific value of the fuel,
N corresponds to the speed of rotation of the rotation shaft into/from which torque is injected/removed by said at least one electric machine,
C_1 is a constant value, and
n corresponds to the efficiency of the gas generator.
2. The method as claimed in claim 1 , in which the efficiency q of the gas generator is expressed in the following form:
η
=
1
-
1
(
1
+
γ
-
1
2
×
M
0
2
)
×
OPR
γ
-
1
γ
expression in which:
M corresponds to the Mach speed,
y corresponds to a ratio between an isobaric heat capacity and an isochoric heat capacity,
OPR corresponds to an overall pressure rate of the gas generator.
3. The method as claimed in claim 1 , in which said at least one operability limit corresponds to any one of the following parameters:
a C/P limit,
a limit relative to a mechanical speed N 1 ,
a limit relative to a mechanical speed N 2 ,
a limit relative to an exhaust gas temperature at the inlet of a low-pressure turbine of the turbomachine.
4. A non-transitory computer-readable medium having stored thereon instructions which, when executed by a processor, cause the processor to implement the method of claim 1 .
5. A control system—for controlling a turbomachine—comprising a gas generator comprising a combustion chamber, a low-pressure rotation shaft and a high-pressure rotation shaft, the turbomachine comprising at least one electric machine forming a device for injecting torque into/removing torque from one of said rotation shafts, said control system comprising a fuel control loop for determining a fuel flow setpoint into the combustion chamber, said fuel control loop comprising:
a monitoring module for monitoring the turbomachine, configured to detect if at least one operability limit of said turbomachine is reached,
a determination module, configured to determine a corrected fuel flow setpoint if said at least one operability limit is reached, said corrected fuel flow setpoint exhibiting a difference, referred to as the “flow difference”, in relation to the current fuel flow setpoint, said control system also comprising a torque control loop for determining a torque setpoint for said at least one electric machine, said torque control loop comprising:
a first determination module, configured to determine a torque correction quantity as a function of said flow difference,
a second determination module, configured to determine said torque setpoint as a function of said torque correction quantity
wherein the torque correction quantity—is determined to be equal to:
EC_DEB
×
FHV
×
η
C
_
1
×
N
expression in which:
EC_DEB corresponds to the flow difference,
FHV corresponds to the calorific value of the fuel,
N corresponds to the speed of rotation of the rotation shaft into/from which torque is injected/removed by said at least one electric machine,
C_1 is a constant value, and
n corresponds to the efficiency of the gas generator.
6. A turbomachine comprising a gas generator comprising a combustion chamber, a low-pressure rotation shaft and a high-pressure rotation shaft, the turbomachine comprising at least one electric machine-forming a device for injecting torque into/removing torque from at least one of said rotation shafts and a control system as claimed in claim 5 .
7. An aircraft comprising a turbomachine as claimed in claim 6 .