阅读说明：本技术 压缩机控制方法、控制装置及空调器 (Compressor control method and device and air conditioner ) 是由 贾新旭 邵海柱 耿焱 时斌 丛安平 刘春丽 于 2020-04-08 设计创作，主要内容包括：本发明公开了一种压缩机控制方法、控制装置及空调器,所述方法包括：压缩机启动后,实时获取当前转速设定值、当前q轴电流设定值；根据当前转速设定值、当前q轴电流设定值及已知的磁通量、d轴电感、q轴电感和限值电压,确定当前弱磁控制的d轴电流i<Sub>d1</Sub>；根据当前q轴电流设定值、磁通量、d轴电感、q轴电感,确定当前MTPA控制的d轴电流i<Sub>d2</Sub>；选取所述i<Sub>d1</Sub>和所述i<Sub>d2</Sub>中的绝对值较小者,确定为当前d轴电流设定值；将当前d轴电流设定值和当前q轴电流设定值作为输入量输入到压缩机控制用电流环中,对压缩机进行控制。应用本发明,可以解决现有技术的压缩机在MTPA控制和弱磁控制的切换过程中容易产生电流冲击而造成压缩机运行不平稳的技术问题。(The invention discloses a compressor control method, a control device and an air conditioner, wherein the method comprises the following steps: after a compressor is started, acquiring a current rotating speed set value and a current q-axis current set value in real time; determining the current d-axis current i under field weakening control according to the current set value of the rotating speed, the current set value of the q-axis current and the known magnetic flux, d-axis inductance, q-axis inductance and limit voltage d1 (ii) a Determining the current MTPA controlled d-axis current i according to the current q-axis current set value, the magnetic flux, the d-axis inductance and the q-axis inductance d2 (ii) a Selecting the i d1 And said i d2 The smaller absolute value ofDetermining the current d-axis current set value; and inputting the current d-axis current set value and the current q-axis current set value into a current loop for controlling the compressor as input quantities to control the compressor. The invention can solve the technical problem that the compressor in the prior art is unstable in operation because current impact is easy to generate in the switching process of MTPA control and flux weakening control.)

1. A compressor control method, characterized in that the method comprises:

after the compressor is started, the current rotating speed set value omega is obtained in real time_rCurrent q-axis current set value i_qr；

According to the omega_rThe above-mentioned i_qrAnd a known magnetic flux psi_aD-axis inductance Ld, q-axis inductance Lq and limit voltage Vom, and determining d-axis current i of current field weakening control_d1：

Wherein the content of the first and second substances,

according to the i_qrThe psi_aThe Ld and the Lq, determining the current MTPA controlled d-axis current i_d2：

Wherein the content of the first and second substances,

selecting the i_d1And said i_d2The smaller absolute value of the current d-axis current is determined as the current d-axis current set value i_dr；

Will i is_drAnd said i_qrAs input to pressureAnd the compressor is controlled in the current loop for controlling the compressor.

2. The compressor control method according to claim 1, wherein the current q-axis current set value i is obtained in real time_qrThe method specifically comprises the following steps:

obtaining the current rotating speed estimated value of the compressor, and comparing the current rotating speed estimated value with the current rotating speed set value omega_rThe current q-axis current set value i is input into a speed loop for controlling the compressor as an input quantity, and is processed by a PI regulator in the speed loop to output the current q-axis current set value i_qr。

3. The compressor control method according to claim 1, wherein i is set to_drAnd said i_qrThe method is used for inputting the input quantity into a current loop for controlling the compressor to control the compressor, and specifically comprises the following steps:

the current d-axis current set value i_drComparing the current d-axis actual current with the current d-axis actual current, inputting the current d-axis actual current to a PI (proportional integral) regulator in the current loop, and calculating to obtain the current d-axis set voltage; the current q-axis current set value i_qrComparing the current q-axis actual current with the current q-axis actual current, inputting the current q-axis actual current to a PI (proportional integral) regulator in the current loop, and calculating to obtain the current q-axis set voltage;

performing park inverse transformation on the current d-axis set voltage and the current q-axis set voltage to obtain a current alpha-axis set voltage and a current beta-axis set voltage under a two-phase static coordinate system;

and according to the current alpha axis set voltage and the current beta axis set voltage, generating a PWM signal through space vector modulation to control an inverter, outputting a three-phase voltage instruction and driving a compressor to operate.

4. A compressor control method according to any one of claims 1 to 3, characterized in that the current rotational speed set value ω is obtained in real time_rCurrent q-axis current set value i_qrThe method specifically comprises the following steps:

taking the carrier period as a sampling period, wherein the sampling period is one carrier periodIn the period, once detection is executed and the current rotating speed set value omega is obtained_rAnd said current q-axis current setpoint i_qrThe process of (1).

5. A compressor control apparatus, characterized in that the apparatus comprises:

a current rotation speed set value obtaining unit for obtaining the current rotation speed set value omega in real time_r；

A current q-axis current set value obtaining unit for obtaining a current q-axis current set value i in real time_qr；

A current d-axis current set value determination unit for determining ω according to the ω_rThe above-mentioned i_qrAnd a known magnetic flux psi_aD-axis inductance Ld, q-axis inductance Lq and limit voltage Vom, and determining d-axis current i of current field weakening control_d1：

Wherein the content of the first and second substances,

also for according to said i_qrThe psi_aThe Ld and the Lq, determining the current MTPA controlled d-axis current i_d2：

Wherein the content of the first and second substances,

is also used for selecting the i_d1And said i_d2The smaller absolute value of the current d-axis current is determined as the current d-axis current set value i_dr；

A compressor control unit for controlling at least the i_drAnd said i_qrThe input is input into a current loop for controlling the compressor to control the compressor.

6. The compressor control apparatus according to claim 5, wherein the current q-axis current set-point i is obtained in real time_qrThe method specifically comprises the following steps:

obtaining the current rotating speed estimated value of the compressor, and comparing the current rotating speed estimated value with the current rotating speed set value omega_rThe current q-axis current set value i is input into a speed loop for controlling the compressor as an input quantity, and is processed by a PI regulator in the speed loop to output the current q-axis current set value i_qr。

7. The compressor control device according to claim 5, wherein i is set to be equal to_drAnd said i_qrThe method is used for inputting the input quantity into a current loop for controlling the compressor to control the compressor, and specifically comprises the following steps:

the current d-axis current set value i_drComparing the current d-axis actual current with the current d-axis actual current, inputting the current d-axis actual current to a PI (proportional integral) regulator in the current loop, and calculating to obtain the current d-axis set voltage; the current q-axis current set value i_qrComparing the current q-axis actual current with the current q-axis actual current, inputting the current q-axis actual current to a PI (proportional integral) regulator in the current loop, and calculating to obtain the current q-axis set voltage;

performing park inverse transformation on the current d-axis set voltage and the current q-axis set voltage to obtain a current alpha-axis set voltage and a current beta-axis set voltage under a two-phase static coordinate system;

and according to the current alpha axis set voltage and the current beta axis set voltage, generating a PWM signal through space vector modulation to control an inverter, outputting a three-phase voltage instruction and driving a compressor to operate.

8. Compressor control arrangement according to any of claims 5-7, characterized in that the real-time acquisition of the current rotational speed set-point ω is performed_rCurrent q-axis current set value i_qrThe method specifically comprises the following steps:

taking a carrier period as a sampling period, and executing one-time detection and obtaining the current rotating speed set value omega in one carrier period_rAnd said current q-axis current setpoint i_qrThe process of (1).

9. An air conditioner including a compressor, characterized in that the air conditioner further includes a compressor control device as claimed in any one of the preceding claims 5 to 7.

10. A readable storage medium, characterized in that a readable program is stored therein, which readable program is configured to execute the compressor control method of any of the above claims 1 to 4 when executed.

Technical Field

The invention belongs to the technical field of motor control, and particularly relates to a compressor control method, a compressor control device and an air conditioner.

Background

At present, in the field of air conditioner compressor driving, a variable frequency driving mode is widely adopted. The frequency conversion is to rectify single-phase or three-phase electricity into direct current and then invert the direct current into UVW three-phase electricity through a power module to drive a motor.

The compressor adopting the permanent magnet synchronous motor has reluctance torque because the d-axis inductance and the q-axis inductance of the permanent magnet synchronous motor are not equal, so that the generated back electromotive force is smaller than the maximum voltage limit value in the low-frequency and normal operation range, and can be controlled by MTPA (maximum torque current ratio) to reduce the copper consumption of the motor and improve the operation efficiency. When the motor speed is increased, the counter electromotive force generated by the magnetic field is increased, and when the maximum voltage limit is reached, if the compressor frequency is further widened, FW (field weakening) control is adopted to increase the d-axis current, weaken the magnetic flux of the stator permanent magnet and widen the rotating speed range.

In the control of the compressor, switching between the MTPA control and the FW control is particularly important. In the prior art, generally, whether the back electromotive force reaches the maximum voltage limit value is used as a judgment basis for switching control. However, in practical applications, during the switching process of the MTPA control and the FW control executed according to the judgment basis, a large current surge is easily generated, which affects the output performance of the inverter, and causes the compressor to step out and the operation to be unstable.

Disclosure of Invention

The invention aims to provide a compressor control method, a control device and an air conditioner, which solve the technical problem that the compressor in the prior art is unstable in operation due to current impact easily generated in the switching process of MTPA control and flux weakening control.

In order to realize the purpose of the invention, the invention is realized by adopting the following technical scheme:

a compressor control method comprising:

after the compressor is started, the current rotating speed set value omega is obtained in real time_rCurrent q-axis current set value i_qr；

According to the omega_rThe above-mentioned i_qrAnd a known magnetic flux psi_aD-axis inductance Ld, q-axis inductance Lq and limit voltage Vom, and determining d-axis current i of current field weakening control_d1：

Wherein the content of the first and second substances,

according to the i_qrThe psi_aThe Ld and the Lq, determining the current MTPA controlled d-axis current i_d2：

Wherein the content of the first and second substances,

selecting the i_d1And said i_d2The smaller absolute value of the current d-axis current is determined as the current d-axis current set value i_dr；

Will i is_drAnd said i_qrThe input is input into a current loop for controlling the compressor to control the compressor.

The control method of the compressor obtains the current q-axis current set value i in real time_qrThe method specifically comprises the following steps:

obtaining the current rotating speed estimated value of the compressor, and comparing the current rotating speed estimated value with the current rotating speed set value omega_rThe current q-axis current set value i is input into a speed loop for controlling the compressor as an input quantity, and is processed by a PI regulator in the speed loop to output the current q-axis current set value i_qr。

The compressor control method as described above, the i_drAnd said i_qrThe method is used for inputting the input quantity into a current loop for controlling the compressor to control the compressor, and specifically comprises the following steps:

the current d-axis current set value i_drComparing the current d-axis actual current with the current d-axis actual current, inputting the current d-axis actual current to a PI (proportional integral) regulator in the current loop, and calculating to obtain the current d-axis set voltage; the current q-axis current set value i_qrComparing the current q-axis actual current with the current q-axis actual current, inputting the current q-axis actual current to a PI (proportional integral) regulator in the current loop, and calculating to obtain the current q-axis set voltage;

performing park inverse transformation on the current d-axis set voltage and the current q-axis set voltage to obtain a current alpha-axis set voltage and a current beta-axis set voltage under a two-phase static coordinate system;

and according to the current alpha axis set voltage and the current beta axis set voltage, generating a PWM signal through space vector modulation to control an inverter, outputting a three-phase voltage instruction and driving a compressor to operate.

The compressor control method obtains the current set value omega of the rotating speed in real time_rCurrent q-axis current set value i_qrThe method specifically comprises the following steps:

taking a carrier period as a sampling period, and executing one-time detection and obtaining the current rotating speed set value omega in one carrier period_rAnd said current q-axis current setpoint i_qrThe process of (1).

A compressor control apparatus comprising:

a current rotation speed set value obtaining unit for obtaining the current rotation speed set value in real timeConstant value omega_r；

A current q-axis current set value obtaining unit for obtaining a current q-axis current set value i in real time_qr；

A current d-axis current set value determination unit for determining ω according to the ω_rThe above-mentioned i_qrAnd a known magnetic flux psi_aD-axis inductance Ld, q-axis inductance Lq and limit voltage Vom, and determining d-axis current i of current field weakening control_d1：

Wherein the content of the first and second substances,

also for according to said i_qrThe psi_aThe Ld and the Lq, determining the current MTPA controlled d-axis current i_d2：

Wherein the content of the first and second substances,

is also used for selecting the i_d1And said i_d2The smaller absolute value of the current d-axis current is determined as the current d-axis current set value i_dr；

A compressor control unit for controlling at least the i_drAnd said i_qrThe input is input into a current loop for controlling the compressor to control the compressor.

The compressor control device obtains the current q-axis current set value i in real time_qrThe method specifically comprises the following steps:

obtaining the current rotating speed estimated value of the compressor, and comparing the current rotating speed estimated value with the current rotating speed set value omega_rThe current q-axis current set value i is input into a speed loop for controlling the compressor as an input quantity, and is processed by a PI regulator in the speed loop to output the current q-axis current set value i_qr。

The compressor control device described above may control the i_drAnd said i_qrThe method is used for inputting the input quantity into a current loop for controlling the compressor to control the compressor, and specifically comprises the following steps:

the current d-axis current set value i_drComparing the current d-axis actual current with the current d-axis actual current, inputting the current d-axis actual current to a PI (proportional integral) regulator in the current loop, and calculating to obtain the current d-axis set voltage; the current q-axis current set value i_qrComparing the current q-axis actual current with the current q-axis actual current, inputting the current q-axis actual current to a PI (proportional integral) regulator in the current loop, and calculating to obtain the current q-axis set voltage;

performing park inverse transformation on the current d-axis set voltage and the current q-axis set voltage to obtain a current alpha-axis set voltage and a current beta-axis set voltage under a two-phase static coordinate system;

and according to the current alpha axis set voltage and the current beta axis set voltage, generating a PWM signal through space vector modulation to control an inverter, outputting a three-phase voltage instruction and driving a compressor to operate.

The compressor control device obtains the current rotation speed set value omega in real time_rCurrent q-axis current set value i_qrThe method specifically comprises the following steps:

taking a carrier period as a sampling period, and executing one-time detection and obtaining the current rotating speed set value omega in one carrier period_rAnd said current q-axis current setpoint i_qrThe process of (1).

An air conditioner comprises a compressor and further comprises the compressor control device.

The present invention also provides a readable storage medium having a readable program stored therein, the readable program being configured to execute the above-mentioned compressor control method when executed.

Compared with the prior art, the invention has the advantages and positive effects that: according to the compressor control method, the control device and the air conditioner, the current d-axis current controlled by weak magnetism obtained based on the weak magnetism control principle and the current d-axis current controlled by MTPA obtained based on the MTPA control principle are determined in real time, the d-axis current with a smaller absolute value in the two currents is taken as the current d-axis current set value to participate in the current loop control of the compressor, and therefore not only can the stable switching of the current from the MTPA control to the weak magnetism control in a high-frequency stage be realized, the compressor can stably operate in both a low-frequency field and a high-frequency field, but also the input power can be minimized under the condition of certain output torque, and the optimization of the input power is realized; in addition, the scheme provided by the invention is easy to realize the switching between the MTPA control and the flux weakening control, and is convenient to be widely adopted in the field of compressor control.

Other features and advantages of the present invention will become more apparent from the following detailed description of the invention when taken in conjunction with the accompanying drawings.

Drawings

In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the drawings needed to be used in the embodiments are briefly introduced below, and it is obvious that the drawings in the following description are some embodiments of the present invention, and it is obvious for those skilled in the art to obtain other drawings based on these drawings without creative efforts.

FIG. 1 is a flow chart of one embodiment of a compressor control method according to the present invention;

FIG. 2 is a schematic diagram of the control principle of FIG. 1;

FIG. 3 is a waveform diagram generated by applying the method of FIG. 1;

fig. 4 is a block diagram showing the structure of one embodiment of the compressor control device according to the present invention.

Detailed Description

In order to make the objects, technical solutions and advantages of the present invention more apparent, the present invention will be described in further detail with reference to the accompanying drawings and examples.

Referring to fig. 1, a flow chart of an embodiment of a compressor control method according to the present invention is shown. Specifically, in order to solve the problem that the current surge is easily generated during the switching process of the MTPA control and the flux weakening control in the prior art, which causes the unstable operation of the compressor, the embodiment adopts a process having the following steps to realize the control of the compressor.

Step 11: and after the compressor is started, acquiring a current set value of the rotating speed and a current set value of the q-axis current in real time.

Obtaining the current set value omega of the rotating speed in real time_rCurrent q-axis current set value i_qrThe method specifically comprises the following steps:

taking the carrier period as a sampling period, and performing detection once and acquiring the current rotating speed set value omega in one carrier period_rAnd said current q-axis current setpoint i_qrThe process of (1). Of course, other ways of setting the sampling period may also be adopted, for example, the sampling period is set to other known fixed values, so as to reasonably acquire the current set value ω of the rotational speed_rCurrent q-axis current setpoint i_qrIt is preferable.

For the current speed set value omega_rIs a value that the compressor control system can conveniently obtain. The rotational speed of the compressor does not reach the final set rotational speed immediately, but gradually increases at a constant acceleration. For example, if the rotational speed setting is 60rps and the set acceleration is 4rps/s, the rotational speed setting for the first second is 4rps and the rotational speed setting for the second is 8rps, and after 15s, the rotational speed setting reaches 60 rps. Then, depending on the sampling period, the current speed set point is the speed set point in the second, and this value should be 8rps instead of 60 rps.

Current set value i for current q axis_qrPreferably, this is achieved by a speed loop for compressor control. Specifically, referring to the schematic control diagram shown in fig. 2, the current speed estimate ω of the compressor is obtained, and the current speed estimate ω and the current speed set value ω are compared_rThe current q-axis current is input into a speed loop for controlling the compressor as an input quantity, processed by a PI regulator in the speed loop, and output as a current q-axis current set value i_qr. The current estimated value ω of the rotational speed can be estimated by means of speed position detection, which is a specific estimation method in the prior art and is not described in detail herein.

Step 12: determining the d-axis current of the current weak magnetic control and the d-axis current of the current MTPA control.

The current d-axis current for flux weakening control refers to a d-axis current value calculated according to a flux weakening control principle. Specifically, the current rotation speed set value ω is used_rCurrent q-axis current set value i_qrAnd a known magnetic flux psi_aD-axis inductance Ld, q-axis inductance Lq and limit voltage Vom, and determining d-axis current i of current field weakening control_d1The formula is determined as follows:

wherein the content of the first and second substances,

in the above formula, ω_rAnd i_qrMagnetic flux psi obtained by the method of step 11_aThe d-axis inductance Ld and the q-axis inductance Lq are the rated parameters of the motor, which are known after the compressor is determined. The limit voltage Vom is a limit voltage for the weak magnetic switching, and the value is preset according to actual conditions and is also known.

In the above formula, d-axis current i is determined_d1And (3) representing the square value by using b for the simple expression of the formula, wherein the value of b is positive. The following is derived with respect to the formula:

according to the flux weakening control principle, the following formula exists:

when L is_di_d1+ψ_aWhen the content is more than or equal to 0, the content is satisfied

When L is_di_d1+ψ_aWhen the concentration is less than or equal to 0, the requirement is met

The current d-axis current controlled by the MTPA is a d-axis current value calculated according to the MTPA control principle. Specifically, the current q-axis current set value i is used_qrMagnetic flux psi_aD-axis inductance Ld and q-axis inductance Lq, and determining d-axis current i controlled by the current MTPA_d2：

Wherein the content of the first and second substances,

in the above formula, the meaning of each parameter is the same as that in the d-axis current determining the current field weakening control.

Step 13: and selecting the smaller absolute value of the two d-axis currents, and determining the smaller absolute value as the current d-axis current set value.

The d-axis current i of the current field weakening control is determined in step 12_d1And current MTPA controlled d-axis current i_d2And then, taking absolute values of the two currents, comparing the absolute values, and determining the current value with the smaller absolute value as the current d-axis current set value.

Step 14: and inputting the current d-axis current set value and the current q-axis current set value into a current loop for controlling the compressor as input quantities to control the compressor.

After the d-axis current setpoint and the q-axis current setpoint are determined, the compressor may be controlled using the current loop. Specifically, referring to the control schematic shown in FIG. 2, the current d-axis current setpoint i_drComparing the current d-axis actual current Id with the current d-axis actual current, inputting the current d-axis actual current Id to a PI regulator in a current ring, and calculating to obtain a current d-axis set voltage Vd; current q-axis current setpoint i_qrAnd comparing the current q-axis actual current Iq with the current q-axis actual current Iq, inputting the current q-axis actual current Iq into a PI regulator in a current loop, and calculating to obtain the current q-axis set voltage Vq. The current d-axis actual current Id and the current q-axis actual current Iq are obtained in the prior art, and are not repeated here.

Then, the current d-axis setting voltage Vd and the current q-axis setting voltage Vq are subjected to park inverse transformation to obtain a current α -axis setting voltage V α and a current β -axis setting voltage V β in the two-phase stationary coordinate system.

And then, according to the current alpha axis set voltage V alpha and the current beta axis set voltage V beta, generating a PWM signal through space vector modulation to control an inverter, outputting a three-phase voltage instruction and driving a compressor to operate.

Fig. 3 is a waveform diagram generated by applying the method of fig. 1, wherein the horizontal axis represents time, Idr and Iqr are a d-axis current set value waveform and a q-axis current set value waveform, Iu is a U-phase input current waveform of the compressor, and F _ ph is a field weakening flag. Through waveform analysis, the waveform of the U-phase input current of the compressor is stable and does not have sudden change at the switching point of MTPA control and flux weakening control; the whole U-phase input waveform is a normal sine waveform and has no obvious distortion. And the d-axis current set value and the q-axis current set value are normal and have no sudden change, so that the requirement of stable operation is met.

The method of the embodiment is adopted to control the compressor, the current flux weakening control d-axis current obtained based on the flux weakening control principle and the current MTPA control d-axis current obtained based on the MTPA control principle are determined in real time, the d-axis current with the smaller absolute value in the two currents is taken as the current d-axis current set value to participate in the current loop control of the compressor, and therefore not only can the stable switching of the current from the MTPA control to the flux weakening control in the high-frequency stage be realized, the compressor can stably run in both the low-frequency field and the high-frequency field, but also the input power can be minimized under the condition of certain output torque, and the optimization of the input power is realized. In addition, by adopting the scheme provided by the embodiment, the whole treatment process is simple and easy to implement, the switching between the MTPA control and the flux weakening control is easy to realize, and the method is convenient to widely adopt in the field of compressor control.

Fig. 4 is a block diagram illustrating an embodiment of a compressor control apparatus according to the present invention, and more particularly, to an embodiment of a compressor control apparatus for solving the problem of unstable operation of a compressor caused by current surge during switching between MTPA control and flux weakening control in the prior art. The compressor control device of this embodiment includes the following structural units, and the functions and mutual connection relationships of the structural units are as follows:

a current rotation speed set value obtaining unit 21 for obtaining the current rotation speed set value ω in real time_r。

A current q-axis current set value obtaining unit 22 for obtaining a current q-axis current set value i in real time_qr。

A current d-axis current set value determining unit 23 for determining a current set value ω according to the current rotational speed set value ω output by the current rotational speed set value obtaining unit 21_rA current q-axis current set value i output by the current q-axis current set value acquisition unit 22_qrAnd a known magnetic flux psi_aD-axis inductance Ld, q-axis inductance Lq and limit voltage Vom, and determining d-axis current i of current field weakening control_d1(ii) a Also used according to i_qr、ψ_aLd and Lq, determining the current MTPA controlled d-axis current i_d2(ii) a And also for selecting i_d1And i_d2The smaller absolute value of the current d-axis current is determined as the current d-axis current set value i_dr。

A compressor control unit at least for outputting the present d-axis current set value i outputted by the present d-axis current set value determination unit 23_drAnd a current q-axis current set value i output from the current q-axis current set value acquisition unit 22_qrThe input is input into a current loop for controlling the compressor to control the compressor.

The compressor control device with the above structure, in combination with the compressor control system, runs the corresponding software program to control the compressor according to the process of the method embodiment of fig. 1, and produces the same technical effects as the method embodiment.

The compressor control device described in the above embodiment may be applied to a variable frequency air conditioner, and particularly, to a variable frequency air conditioner without an electrolytic capacitor, so as to control an air conditioner compressor.

Embodiments of the present invention also provide a readable storage medium in which a readable program is stored, the readable program being configured to execute the compressor control method of the above embodiments when executed.

The above examples are only intended to illustrate the technical solution of the present invention, but not to limit it; although the present invention has been described in detail with reference to the foregoing embodiments, it will be apparent to those skilled in the art that various changes may be made and equivalents may be substituted for elements thereof; and such modifications or substitutions do not depart from the spirit and scope of the corresponding technical solutions.