CONTROL FOR ELECTRICAL HEATING CIRCUIT, IN PARTICULAR FOR MOTOR VEHICLE

• US 20160143090A1
• Filed: 05/15/2014
• Published: 05/19/2016
• Est. Priority Date: 06/17/2013
• Status: Active Grant

• Current Assignee: Valeo Systemes Thermiques (Valeo SE)
• Original Assignee: Valeo Systemes Thermiques (Valeo SE)
• Inventors: Puzenat, Bertrand, Tellier, Laurent
• Granted Patent: US 10,477,621 B2
• Time in Patent Office: Days
• US Class Current: 1/1
• CPC Class Codes: B60H 1/2218 controlling the operation of electric heaters
• CPC Class Codes: H05B 1/02 Automatic switching arrangements specially adapted to apparatus ; Control of heating devices thermally-actuated switches H01H37/00
• CPC Class Codes: H05B 1/0236 for vehicles

Abstract

A device (1) for controlling an electrical heating circuit (2) comprising a number N of heating elements (21-23) connected in parallel, comprises, according to the invention: N electronic switches (T₁-T₃), each able to be connected in series with one of the N heating elements (21-23); a module (10) able to receive a power setpoint in the form of a control signal (PWM) with duty ratio varying as a function of power; means (12) for extracting a mean value (formula (I)) of the control signal (PWM) received; and P comparators (C₁-C₃), the integer P being less than or equal to N, which are able to compare the mean value (formula (I)) extracted with P distinct threshold values (Ref₁-Ref₃) and to generate P comparison signals (S₁-S₃), each comparison signal serving to control a toggling of the electronic switch (T₁-T₃) associated with at least one heating element into the open or closed position.

Claims

1. A method for controlling an electric heating circuit (2) comprising a number N of heating elements connected in parallel, each heating element being able to be connected in series with an associated electronic switch the method comprising:

reception of a power setpoint in the form of a pulse width modulation (PWM) control signal of variable duty cycle as a function of the power;

extraction of an average value of the received PWM control signal;

execution of P comparisons, the integer P being less than or equal to N, of the extracted average value with P distinct threshold values and generation of P comparison signals,

each comparison signal being used to control a switching over of the electronic switch associated with at least one heating element to the open or closed position.

2. The method as claimed in claim 1, in which the integer P is equal to N, such that each comparison signal serves to control the electronic switch associated with a single heating element.

3. The method as claimed in claim 1, wherein, for each of the P comparisons, the comparison signal (S₁-S₃) generated is suitable for:

controlling a switching over of the associated electronic switch to the open position if the extracted average value is less than the threshold value;

controlling a switching over of the associated electronic switch to the closed position otherwise.

4. A device for controlling an electric heating circuit comprising a number N of heating elements connected in parallel, the control device comprising:

N electronic switches, each able to be connected in series with one of the N heating elements;

an electronic reception module suitable for receiving a power setpoint in the form of a pulse width modulation (PWM) control signal of variable duty cycle as a function of the power;

means for extracting an average value of the PWM control signal received; and

P comparators, the integer P being less than or equal to N, suitable for comparing the extracted average value with P distinct threshold values and generating P comparison signals, each comparison signal serving to control a switching over of the electronic switch associated with at least one heating element to the open or closed position.

5. The control device as claimed in claim 4, further comprising means for generating the P threshold values.

6. The control device as claimed in claim 5, wherein said generation means comprise a divider bridge with P+1 resistors in series, subject to a reference voltage, each link point between two resistors of the divider bridge giving an increasing threshold value between two successive link points.

7. The control device as claimed in claim 4, wherein each comparator is suitable for delivering a comparison signal suitable for:

controlling a switching over of the associated electronic switch to the open position if the extracted average value is less than the threshold value; and

controlling a switching over of the associated electronic switch to the closed position otherwise.