Variable frequency drive and method of its air cooling

1. A variable frequency drive air cooling system comprising:

a cabinet [ 1 ], a double-circuit forced air cooling system, power and low-current electronic components, a control unit;

wherein said cabinet contains a sealed compartment [ 2 ] and a ventilated compartment [ 24 ];

the sealed compartment [ 2 ] comprising a first air circuit [ 32 ], local modules [ 3 ; 4 ; 17 ] with the power and the low-current electronic components;

the ventilated compartment [ 24 ] comprising a second air circuit [ 25 ];

wherein said first air circuit [ 32 ] and the second air circuit [ 25 ] are designed in thermal communication via a number of air heat exchangers [ 22 ] installed within the ventilated compartment [ 24 ], and

the first air circuit [ 32 ] is arranged within the sealed compartment [ 2 ] and formed by an internal air channel [ 18 ] which is formed around a perimeter of each of the local modules [ 3 ; 4 ; 17 ] of the sealed compartment [ 2 ];

wherein each of the local modules [ 3 ; 4 ] is equipped with a circulation fan [ 26 ] installed within a sealed air channel [ 28 ];

wherein the sealed air channel [ 28 ] is arranged within the ventilated compartment [ 24 ] between air heat exchangers [ 22 ] of a first pair [ 22 . 1 ] which are installed within straight air channels [ 23 ];

wherein the internal air channel [ 18 ] is connected to the first pair [ 22 . 1 ] of air heat exchangers [ 22 ] and formed as an air barrier between the cabinet enclosure and each of the local modules [ 3 ; 4 ] of the sealed compartment;

wherein the first pair [ 22 . 1 ] of said number of air heat exchangers [ 22 ] is equipped with the circulation fan [ 26 ];

wherein the second air circuit [ 25 ] contains the straight air channels [ 23 ] arranged within the ventilated compartment [ 24 ] adjacent to the sealed compartment [ 2 ],

wherein each of said straight air channels [ 23 ] comprising a second pair [ 22 . 2 ] of air heat exchangers [ 22 ] with a blast fan [ 27 ] between them.

2. The variable frequency drive of claim 1 wherein the cabinet [ 1 ] is designed with a four sides access,

wherein a front side of the cabinet [ 1 ] is equipped with sealed doors [ 13 ] of each local module of the sealed compartment [ 2 ], as well as a control unit module [ 17 ] with an integrated microprocessor controller [ 33 ],

wherein one of said local modules of the sealed compartment contains a transformer [ 6 ],

wherein one of said local modules of the sealed compartment contains a number of power cells [ 12 ],

wherein other sides of the cabinet [ 1 ] comprising a sealed terminal chamber [ 11 ; 15 ] and assembly covers [ 16 ] of the circulation fan [ 26 ] and the blast fan [ 27 ] and the air heat exchangers [ 22 ].

3. The variable frequency drive of claim 1 wherein one of side walls of the cabinet [ 1 ] is equipped with the transformer assembly cover [ 10 ].

4. The variable frequency drive of claim 1 wherein at least one circulation fan [ 26 ] is installed within the sealed air channel [ 28 ] arranged between the air heat exchangers [ 22 ] of the first pair [ 22 . 1 ],

wherein the at least one circulation fan [ 26 ] is aligned with air ways [ 35 . 2 ] of the air heat exchangers [ 22 ] of the first pair [ 22 . 1 ].

5. The variable frequency drive of claim 1 wherein each of the air heat exchangers [ 22 ] consists of laminated sandwiched plates [ 29 ] comprising metal plates with a polymer sandwiched layer between them,

wherein the laminated sandwiched plates [ 29 ] is divided by spacing elements [ 30 ] installed periodically and connected by coupling rods [ 31 ] installed around of the perimeter of the heat exchanger.

6. The variable frequency drive of claim 1 wherein each of the air heat exchangers contains at least two divided air ways [ 35 . 1 ; 35 . 2 ], one of which is orthogonal to another,

wherein said two air ways [ 35 . 1 ; 35 . 2 ] are configured between each three neighboring laminated sandwich plates [ 29 ].

7. The variable frequency drive of claim 1 wherein the control unit is cased in the local module [ 17 ] and installed between two adjacent local modules [ 3 ; 4 ] of the sealed compartment [ 2 ] within the internal air channel [ 18 ].

8. A variable frequency drive air cooling method comprising:

forming a double-circuit forced air cooling system;

arranging a first air circuit [ 32 ] within a sealed compartment [ 2 ] of the variable frequency drive cabinet [ 1 ];

providing a second air circuit [ 25 ] within a ventilated compartment [ 24 ] of the variable frequency drive cabinet [ 1 ];

wherein said first and second air circuit [ 32 ; 25 ] are designed in a thermal communication via a number of air heat exchangers [ 22 ] installed within the ventilated compartment [ 24 ];

dividing the sealed compartment [ 2 ] by local modules [ 3 ; 4 ] with a power and low-current electronic components;

forming an internal air channels [ 18 ] around of a perimeter of the local modules [ 3 ; 4 :] of the sealed compartment [ 2 ],

wherein each local module [ 3 ; 4 ] is equipped with at least one circulation fan [ 26 ];

positioning the circulation fan [ 26 ] within a sealed air channel [ 28 ], and

forming the sealed air channel [ 28 ] within the ventilated compartment [ 24 ] between air heat exchangers [ 22 ] of a first pair [ 22 . 1 ] which are installed within straight air channels [ 23 ],

wherein the circulation fan [ 26 ] is aligned with air ways [ 35 . 2 ] of the air heat exchangers of the first pair [ 22 . 1 ];

forming an air loop which is moving within each of the local modules [ 3 ; 4 ] with using the circulation fan [ 26 ], and

forming a cooling air barrier between the cabinet [ 1 ] enclosure and each local module [ 3 ; 4 ] of the sealed compartment [ 2 ];

directing the air loop of each local module [ 3 ; 4 ] through the air heat exchangers [ 22 ], and

installing the air heat exchangers in a second pair [ 22 . 2 ] within one of the straight air flow channel [ 23 ] arranged within the ventilated compartment [ 24 ] which is adjacent to the sealed compartment [ 2 ],

wherein each pair [ 22 . 2 ] of air heat exchangers comprising a blast fan [ 27 ].

9. The method of the air cooling of the variable frequency drive of claim 8 wherein controlling the capacity of the circulation and/or blast fan via a control unit depending on temperature within the sealed compartment [ 2 ] of each of the local modules [ 3 ; 4 ;].

10. The method of the air cooling of the variable frequency drive of claim 8 wherein detecting an air humidity inside of the sealed compartment [ 2 ],

removing moisture from the air by collecting the moisture on thermoelectric devices installed in the internal air channels [ 18 ].