Heater controller, heating device, and heater control method

Abstract

To provide a heater controller that suppresses the generation of electrical noise associated with control. [Solution] A heater controller for controlling a heater. The heater has a plurality of heating sections, including a first heating section and a second heating section, a first switching element connected to the first heating section, and a second switching element connected to the second heating section. The heater controller controls the power supplied to the plurality of heating sections by controlling each of the first switching element and the second switching element, and maintains the other of the first and second switching elements in the off or on state during the period when one of the first and second switching elements is switching.

Description

[Technical Field]

[0001] This disclosure relates to a heater controller, a heating device, and a heater control method. [Background technology]

[0002] In transportation equipment such as electric vehicles and internal combustion engine vehicles, and various other types of equipment, heating devices are used to supply heat to the necessary parts within the equipment. The output (heat generation) of the heating device is generally controlled by a controller. Patent Document 1 discloses a heater drive device that performs PWM control. [Prior art documents] [Patent Documents]

[0003] [Patent Document 1] Japanese Patent Publication No. 2018-152273 [Overview of the project] [Problems that the invention aims to solve]

[0004] When controlling the output of a heating device using control methods such as PWM control, electrical noise may be generated during the control process. While it is desirable to minimize electrical noise, Patent Document 1 does not consider suppressing electrical noise generated during PWM control.

[0005] This disclosure aims to provide a heater controller, a heating device, and a heater control method that suppress the generation of electrical noise associated with control. [Means for solving the problem]

[0006] In accordance with the first aspect of this disclosure, Heater control heater controller, The aforementioned heater is Multiple heating sections, including a first heating section and a second heating section, A first switching element connected to the first heating section, It has a second switching element connected to the second heating section, The aforementioned heater controller is The power supplied to the plurality of heating units is controlled by controlling each of the first switching element and the second switching element. A heater controller is provided that maintains the other of the first and second switching elements in the off or on state during the period in which one of the first and second switching elements is switched.

[0007] In accordance with the second aspect of this disclosure, Multiple heating sections, including a first heating section and a second heating section, A first switching element connected to the first heating section, A second switching element connected to the second heating section, A heater equipped with, A heater controller according to the first embodiment, A heating device is provided that includes the following:

[0008] In accordance with the third aspect of this disclosure, A heater control method, The aforementioned heater is Multiple heating sections, including a first heating section and a second heating section, A first switching element connected to the first heating section, It has a second switching element connected to the second heating section, The power supplied to the plurality of heating units is controlled by controlling each of the first switching element and the second switching element, A heater control method is provided, which includes keeping the other of the first and second switching elements on or off during the period in which one of the first and second switching elements is switched. [Effects of the Invention]

[0009] This disclosure provides a heater controller, a heating device, and a heater control method in which the generation of electrical noise associated with control is suppressed. [Brief explanation of the drawing]

[0010] [Figure 1] Figure 1 is an explanatory diagram showing the configuration of the heating system according to the embodiment. [Figure 2] Figure 2 is a block diagram showing the electrical configuration of the heating device according to the embodiment. [Figure 3] Figure 3(a) is a perspective view of a ceramic heater. Figure 3(b) is a cross-sectional view of the ceramic heater shown in Figure 3(a) cut by a plane containing the central axis of the ceramic heater. [Figure 4] Figure 4(a) is a perspective view of the housing containing the ceramic heater. Figure 4(b) is a cross-sectional view of the housing containing the ceramic heater, cut along a plane containing the central axis of the ceramic heater. [Figure 5] Figure 5 is a flowchart showing the procedure for controlling the power supplied to the heating element, as performed by the heater controller. [Figure 6] Figures 6(a), 6(b), and 6(c) are tables showing examples of the relationship between the applied voltage applied to the ceramic heater, the duty cycle of the first switching element, and the duty cycle of the second switching element. [Figure 7] Figure 7(a) shows an example of a PWM signal with a duty cycle of 0%. Figure 7(b) shows an example of a PWM signal with a duty cycle of 25%. Figure 7(c) shows an example of a PWM signal with a duty cycle of 50%. Figure 7(d) shows an example of a PWM signal with a duty cycle of 75%. Figure 7(e) shows an example of a PWM signal with a duty cycle of 100%. [Figure 8]Figure 8(a) is a cross-sectional view of a cylindrical ceramic tube containing two heating elements arranged in the axial direction, cut across a plane containing the central axis of the ceramic tube. Figure 8(b) is a view of a cylindrical ceramic tube containing two heating elements arranged in the circumferential direction, viewed in the axial direction. Figure 8(c) is a plan view of a flat ceramic plate containing two heating elements. [Figure 9] Figure 9 is a block diagram showing the electrical configuration of a modified heating device, excluding the heater controller. [Figure 10] Figure 10 is a block diagram showing the electrical configuration of another modified heating device, excluding the heater controller. [Modes for carrying out the invention]

[0011] <Embodiment> The heater controller HC (Figure 2) and the heating device 10 (Figures 1 and 2) equipped with the heater controller HC of the embodiments of this disclosure will be described with reference to Figures 1 to 10, with an example of how the heating device 10 can be used as part of a heating system 100.

[0012] (Heating system 100) The heating system 100 is installed inside an electric vehicle (EV) and is a system that provides heat to the interior of the electric vehicle.

[0013] As shown in Figure 1, the heating system 100 mainly comprises a heating device 10, a heat dissipation unit 20, a first flow path 31, and a second flow path 32. The heating system 100 further includes a first thermometer 41, a second thermometer 42, and a flow meter 50.

[0014] (Heating device 10) The heating device 10 is a device that provides heat to the liquid L circulating in the circulation channel CCH (described later) of the heating system 100. As shown in Figure 2, the heating device 10 has a heater section HP (an example of a "heater") and a heater controller HC.

[0015] The heater section HP is the part that heats the liquid L (an example of the object to be heated). As shown in Figures 2, 3, and 4, the heater section HP includes a ceramic heater 11, a housing 12 (Figure 4) that houses the ceramic heater 11, and a power supply circuit 13 (Figure 2) that supplies power to the ceramic heater 11.

[0016] As shown in Figure 3(a), the ceramic heater 11 has a cylindrical first ceramic heater 111 (an example of the "first heating section") and a cylindrical second ceramic heater 112 (an example of the "second heating section"). The first ceramic heater 111 and the second ceramic heater 112 are connected coaxially. Therefore, the ceramic heater 11 has a central axis X 11 It is cylindrical in shape and has [a certain characteristic].

[0017] As shown in Figure 3(b), the first ceramic heater 111 has a cylindrical ceramic tube C1 and a heating element H1 disposed inside the ceramic tube C1. The second ceramic heater 112 has a cylindrical ceramic tube C2 and a heating element H2 disposed inside the ceramic tube C2. The heating elements H1 and H2 are thin wires and are arranged, for example, in a meandering pattern throughout the entire interior of the ceramic tubes C1 and C2. In Figure 3(b), the heating element H1 is depicted as two heating elements H1, but these are a series and the power supply is controlled as a whole. The same applies to the heating element H2.

[0018] The ceramics forming the ceramic tubes C1 and C2 can be any ceramic, but alumina (Al2CO3) is one example. The heating elements H1 and H2 can be any heating resistors that generate heat when an electric current is passed through them, but tungsten (W) is one example.

[0019] The housing 12 is a component that houses the ceramic heater 11 and defines a flow path for the liquid L around the ceramic heater 11. The housing 12 may be formed of resin, for example. The housing 12 has a main body portion 121 and a protruding portion 122.

[0020] As shown in Figures 4(a) and 4(b), the main body 121 is along the central axis X121 It is cylindrical in shape, with one end face 121a in the axial direction extending from the central axis X 121 It has a recessed hole 121h that extends along the central axis X. The projection 122 is along the central axis X 122 It is cylindrical in shape and protrudes radially from the outer circumferential surface of the main body 121. The recessed hole 121h of the main body 121 and the through hole 122th of the protruding part 122 are in communication with each other.

[0021] As shown in Figure 4(b), the ceramic heater 11 is fixed to the housing 12 by bringing one surface of the flange FR fixed to the outer circumferential surface of the first ceramic heater 111 into contact with the end surface 121a of the main body portion 121 of the housing 12. When the ceramic heater 11 is fixed to the housing 12, the central axis X of the ceramic heater 11 is 11 and the central axis X of the main body 121 121 These coincide, and the majority of the first ceramic heater 111 and the entirety of the second ceramic heater 112 are located inside the recessed hole 121h.

[0022] With the ceramic heater 11 fixed to the housing 12, a flow path CH is defined by the ceramic heater 11 and the housing 12. The flow path CH starts from one end of the ceramic heater 11 (the end located outside the recess 121h), passes through the central holes of the ceramic cylinders C1 and C2 to the other end of the ceramic heater 11, passes between the outer circumferential surfaces of the ceramic cylinders C1 and C2 and the circumferential surface defining the recess 121h, and reaches one end of the through hole 122th of the projection 122. Then, it passes through the through hole 122th to the other end of the through hole 122th.

[0023] The power supply circuit 13 (Figure 2) is a circuit that supplies power to the heating element H1 of the first ceramic heater 111 and the heating element H2 of the second ceramic heater 112, causing the heating elements H1 and H2 to generate heat.

[0024] As shown in Figure 2, the power supply circuit 13 includes a power supply PS, a first switching element SW1, and a second switching element SW2. The first switching element SW1 and the second switching element SW2 are connected in parallel to the power supply PS.

[0025] Power supply PS is any power source. For example, power supply PS could be a constant current source installed in an electric vehicle.

[0026] Each of the first switching element SW1 and the second switching element SW2 is an element that is switched at high speed by PWM (Pulse Width Modulation) control by the heater controller HC. Examples of each of the first switching element SW1 and the second switching element SW2 are MOSFETs, IGBTs, etc.

[0027] The first switching element SW1 is located between the power supply PS and the heating element H1. The first switching element SW1 can be in an ON state, electrically connecting the power supply PS and the heating element H1, or in an OFF state, electrically disconnecting the power supply PS and the heating element H1. The second switching element SW2 is located between the power supply PS and the heating element H2. The second switching element SW2 can be in an ON state, electrically connecting the power supply PS and the heating element H2, or in an OFF state, electrically disconnecting the power supply PS and the heating element H2. The heater controller HC controls the gate voltage applied to the gates of the first switching element SW1 and the second switching element SW2 by PWM control, thereby turning the first switching element SW1 and the second switching element SW2 into an ON state or an OFF state.

[0028] The heater controller HC controls the voltage applied to the first ceramic heater 111 via the first switching element SW1 and the voltage applied to the second ceramic heater 112 via the second switching element SW2 by switching the first switching element SW1 and the second switching element SW2 using PWM control. In this way, the heater controller HC controls the amount of power supplied from the power supply PS to the heating elements H1 and H2 of the ceramic heater 11. The heater controller HC is composed of, for example, a CPU.

[0029] In the present disclosure and the present invention, the "switching" of the switching element means high-speed switching (high-frequency switching) in which the switching element is rapidly switched between the on state and the off state in order to control the magnitude of the voltage applied through the switching element (and thus the magnitude of the power supplied through the switching element).

[0030] (Heat dissipation part 20) As shown in FIG. 1, the heat dissipation part 20 has a heat exchanger 21 and a blower 22.

[0031] The heat exchanger 21 is a member configured such that heat exchange between the liquid L flowing inside the heat exchanger 21 and the air around the heat exchanger 21 is efficiently performed. The heat exchanger 21 can be formed of aluminum as an example. The heat exchanger 21 has a pipe line CN through which the liquid L flows inside and fins (not shown) provided on the outer peripheral surface of the pipe line CN.

[0032] The blower 22 is a mechanism that sends air toward the heat exchanger 21. In the present embodiment, the blower 22 has a motor MR and a fan FA rotated by the motor.

[0033] (First flow path 31, second flow path 32) The first flow path 31 and the second flow path 32 are each pipe lines through which the liquid L flows inside. One end of the first flow path 31 is connected to the outflow part 10 OUT of the heating device 10, and the other end of the first flow path 31 is connected to the inflow part 20 IN of the heat dissipation part 20. One end of the second flow path 32 is connected to the outflow part 20 OUT of the heat dissipation part 20, and the other end of the second flow path 32 is connected to the inflow part 10 IN of the heating device 10.

[0034] In the present embodiment, as shown in FIG. 4(b), the outflow part 10 OUT of the heating device 10 is located at the tip of the protruding part 122 of the housing 12, and the inflow part 10 IN of the heating device 10 is located at the end of the first ceramic heater 111.

[0035] The flow path CH of the heating device 10, the first flow path 31, the pipeline CN of the heat dissipation section 20, and the second flow path 32 constitute the circulation flow path CCH. The liquid L circulates inside the circulation flow path CCH by a pump (not shown) provided in the circulation flow path CCH.

[0036] (1st thermometer 41, 2nd thermometer 42, flow meter 50) The first thermometer 41 is installed in the vicinity of the heating section 10 of the first flow path 31. The first thermometer 41 measures the temperature of the liquid L flowing out from the heating device 10. The first thermometer 41 is connected to the heater controller HC and sends the measured value to the heater controller HC (Figure 2).

[0037] The second thermometer 42 is located in the region of the second flow path 32 near the heating section 10. The second thermometer 42 measures the temperature of the liquid L flowing into the heating device 10. The second thermometer 42 is connected to the heater controller HC and sends the measured value to the controller HC (Figure 2).

[0038] The flow meter 50 is installed in the second flow path 32. The flow meter 50 measures the flow rate of liquid L flowing through the circulation flow path CCH. The flow meter 50 is connected to the heater controller HC and sends the measured value to the heater controller HC (Figure 2).

[0039] (Operation of heating system 100) The heating system 100 having the above configuration heats the interior of the electric vehicle by operating as follows.

[0040] The heating system 100 heats the interior of the vehicle by circulating liquid L along the circulation channel CCH, thereby heating the liquid L and releasing heat from the liquid L.

[0041] Specifically, first, the heating device 10 heats the liquid L that flows into the flow path CH from the second flow path 32. The heating of the liquid L by the heating device 10 is performed on the liquid L flowing through the flow path CH by the first ceramic heater 111 and the second ceramic heater 112. That is, the object heated by the first ceramic heater 111 and the object heated by the second ceramic heater 112 are both liquid L and are the same as each other. Liquid L can be any liquid such as water or antifreeze.

[0042] At this time, the heater controller HC controls the amount of power supplied to the heating elements H1 and H2 by PWM control of the voltage applied to the heating element H1 of the first ceramic heater 111 and the voltage applied to the heating element H2 of the second ceramic heater 112. This controls the amount of heat generated by the heating elements H1 and H2, i.e., the amount of heat supplied to the liquid L, and controls the temperature of the liquid L to the desired target temperature. Details of this control will be described later.

[0043] Flows through channel CH to outlet 10 OUT The liquid L that flows into the first channel 31 is directed to the inlet 20 of the heat dissipation section 20. IN It flows into the piping CN of the heat exchanger 21 via this.

[0044] At this time, the control unit (not shown) of the electric vehicle rotates the motor MR, sending air from the blower 22 to the heat exchanger 21. The air sent from the blower 22 to the heat exchanger 21 flows around the conduit CN of the heat exchanger 21, exchanges heat with the liquid L in the conduit CN (i.e., its temperature rises), and is then supplied to the passenger compartment of the electric vehicle. This heats the passenger compartment of the electric vehicle. Meanwhile, the temperature of the liquid L in the conduit CN decreases due to heat exchange with the air.

[0045] The heat exchanger 21 may be integrated with the heat exchanger of a heat pump type air conditioner. In this case, when the outside temperature is above a certain temperature, heat exchange takes place between the air supplied from the blower 22 and the refrigerant heated by the heat pump system. When the outside temperature drops and the refrigerant temperature does not rise sufficiently by the heat pump system, the heating system 100 of this embodiment is activated as an auxiliary to perform heat exchange between the air supplied from the blower 22 and the liquid L in the heat exchanger 21.

[0046] The liquid L, whose temperature has decreased due to heat exchange with the air, flows out through outlet 20 OUT It flows into the second channel 32 via the inlet section 10 IN It flows into the heating device 10 via this.

[0047] (Control of power supply to heating elements H1 and H2 by heater controller HC) As described above, the heater controller HC controls the power supplied to heating elements H1 and H2 by PWM control of the voltage applied by the power supply PS to the heating elements H1 and H2. This controls the amount of heat generated by heating elements H1 and H2, and consequently the amount of heat supplied to liquid L, thereby controlling the temperature of liquid L.

[0048] The control of the heat generation amount of heating elements H1 and H2 by the heater controller HC includes the outlet liquid temperature detection step S1, the PI control step S2, the duty cycle determination step S3, and the PWM signal input step S4, as shown in the flowchart of Figure 5.

[0049] In the outlet liquid temperature detection step S1, the heater controller HC acquires a detection value from the first thermometer 41. This detection value is the outlet liquid temperature T of the liquid L. OUT , that is, the outlet 10 of the heating device 10 OUT This indicates the temperature of the liquid L that flowed out from the first channel 31.

[0050] In the PI control process S2, the heater controller HC controls the magnitude of the voltage applied to the ceramic heater 11 (hereinafter referred to as "applied voltage V"). A The outlet liquid temperature T (called ") detected in the outlet liquid temperature detection process S1 OUTIt is determined by PI control based on the following. By using PI control, the applied voltage V A This allows for more accurate determination of the applied voltage V. A This refers to the magnitude of the voltage V applied to the heating element H1 of the first ceramic heater 111. A1 The magnitude of the voltage V applied to the heating element H2 of the second ceramic heater 112 A2 This is the sum of the two values.

[0051] The heater controller HC specifically controls, for example, the outlet liquid temperature T OUT Target value TT OUT and the current outlet liquid temperature T detected in the outlet liquid temperature detection process S1 OUT The temperature difference between ΔT(=TT) and ΔT( OUT -T OUT ) is the input, and the applied voltage V A PI control with output T OUT Target value TT OUT Apply voltage V to approach A To decide.

[0052] In the duty cycle determination step S3, the heater controller HC determines the duty cycle DR1 of the first switching element SW1 and the duty cycle DR2 of the second switching element SW2, and the applied voltage V determined in the PI control step S2. A This is determined based on the following. Here, the duty cycle is a value that indicates the proportion of time that a switching element is in the ON state during switching. The larger the duty cycle, the greater the voltage applied from the power supply PS to the heating elements H1 and H2 via the switching elements SW1 and SW2.

[0053] The heater controller HC specifically determines the duty cycles DR1 and DR2 as follows, for example. In this example, the applied voltage V applied to the ceramic heater 11 A is 0[V]~V MAX The applied voltage V is in the range of [V] and is applied to the first ceramic heater 111. A1 The applied voltage V applied to the second ceramic heater 112 A2 These range from 0[V] to 0.5V respectively.MAX It is in the range of [V]. Also, the output voltage of the power supply PS is 0.5V MAX [V] is

[0054] The heater controller HC first applies the applied voltage V determined in the PI control process S2. A Based on this, the applied voltage V should be applied to the heating element H1 of the first ceramic heater 111. A1 The size, and the applied voltage V to be applied to the heating element H2 of the second ceramic heater 112. A2 Determine the magnitude of the applied voltage V. A1 Magnitude and applied voltage V A2 Based on the size, the duty cycles DR1 and DR2 of the first switching element SW1 and the second switching element SW2 are determined.

[0055] applied voltage V A The value of and the applied voltage V determined by the heater controller HC A1、 V A2 An example of the correspondence between the value of and the duty cycles DR1 and DR2 is shown in Figure 6(a).

[0056] The heater controller HC controls the applied voltage V determined in the PI control process S2. A The voltage range is 0V to 0.5V. MAX [V] (i.e., the applied voltage V) A The maximum applied voltage V MAX If the value is between 0% and 50%, the applied voltage V applied to the heating element H2 of the second ceramic heater 112 is A2 Determined to be 0[V], the applied voltage V is applied to the heating element H1 of the first ceramic heater 111. A1 The applied voltage V A The same value (i.e., 0[V]~0.5V) MAX Determine the applied voltage (one of the values ​​of [V]). Then, the applied voltage V A2 Based on the determination that the voltage is 0[V], the duty cycle DR2 is determined to be 0[%], and the applied voltage V A1 0[V]~0.5V MAXBased on the determination of one of the values ​​of [V], the duty cycle DR1 is set to the corresponding value between 0[%] and 100[%]. In this embodiment, the output voltage of the power supply PS is 0.5V MAX Therefore, the applied voltage V A1 0.125V MAX [V], 0.25V MAX [V], 0.375V MAX [V], 0.5V MAX The duty cycles DR1 required for [V] are 25%, 50%, 75%, and 100%, respectively.

[0057] The heater controller HC controls the applied voltage V determined in the PI control process S2. A 0.5V MAX [V] ~V MAX [V] (i.e., the applied voltage V) A The maximum applied voltage V MAX When [V] is between 50% and 100%, the applied voltage V applied to the heating element H1 of the first ceramic heater 112 is A1 0.5V MAX [V] is determined, and the applied voltage V is applied to the heating element H2 of the second ceramic heater 112. A2 The applied voltage V A From the applied voltage V A1 (i.e., 0.5V) MAX The value obtained by subtracting (i.e., 0[V]~0.5V) MAX Determine the applied voltage (one of the values ​​of [V]). Then, the applied voltage V A1 0.5V MAX Based on the determination that [V], the duty cycle DR1 was determined to be 100[%], and the applied voltage V A2 0[V]~0.5V MAX Based on the determination of one of the values ​​of [V], the duty cycle DR2 is set to the corresponding value between 0[%] and 100[%]. In this embodiment, the output voltage of the power supply PS is 0.5V MAX Therefore, the applied voltage V A2 0.125V MAX [V], 0.25V MAX [V], 0.375V MAX [V], 0.5V MAX[V], the duty ratios DR2 for this are 25 [%], 50 [%], 75 [%], and 100 [%] respectively.

[0058] In this way, the heater controller HC applies the voltage V A When it is 0 [%] to 50 [%] of the maximum applied voltage V MAX , the duty ratio DR2 of the second switching element SW2 is maintained at 0 [%], and the duty ratio DR1 of the first switching element SW1 is changed between 0 [%] and 100 [%]. On the other hand, when the applied voltage V A is 50 [%] to 100 [%] of the maximum applied voltage V MAX , the duty ratio DR1 of the first switching element SW1 is maintained at 100 [%], and the duty ratio DR2 of the second switching element SW2 is changed between 0 [%] and 100 [%]. In other words, during the period when the heater controller HC sets one of the duty ratios DR1 of the first switching element SW1 and DR2 of the second switching element SW2 to a value different from 0 [%] or 100 [%], the other of the duty ratios DR1 of the first switching element SW1 and DR2 of the second switching element SW2 is maintained at 0 [%] or 100 [%]. The reason for this will be described later.

[0059] In the PWM signal input step S4, the heater controller HC inputs PWM signals SG1 and SG2 with the same duty ratios as the duty ratios DR1 and DR2 determined in the duty ratio determination step S3 to the first switching element SW1 and the second switching element SW2, respectively.

[0060] Figure 7(a) shows an example of PWM signals SG1 and SG2 with a duty cycle of 0%, where the ratio of pulse width to period is 0%. Figure 7(b) shows an example of PWM signals SG1 and SG2 with a duty cycle of 25%, where the ratio of pulse width to period is 25%. Figure 7(c) shows an example of PWM signals SG1 and SG2 with a duty cycle of 50%, where the ratio of pulse width to period is 50%. Figure 7(d) shows an example of PWM signals SG1 and SG2 with a duty cycle of 75%, where the ratio of pulse width to period is 75%. Figure 7(e) shows an example of PWM signals SG1 and SG2 with a duty cycle of 100%, where the ratio of pulse width to period is 100%.

[0061] The heater controller HC inputs the PWM signals SG1 shown in Figures 7(a), 7(b), 7(c), 7(d), and 7(e) to the first switching element SW1 when the duty cycle DR1 determined in the duty cycle determination step S3 is 0%, 25%, 50%, 75%, or 100%. Similarly, the heater controller HC inputs the PWM signals SG2 shown in Figures 7(a), 7(b), 7(c), 7(d), and 7(e) to the second switching element SW2 when the duty cycle DR2 determined in the duty cycle determination step S3 is 0%, 25%, 50%, 75%, or 100%.

[0062] (The significance of maintaining either duty cycle DR1 or DR2 at 0% or 100%) As described above, the heater controller HC applies the applied voltage V to the ceramic heater 11. AIn the control of the system, during periods when the duty cycle DR1 of the first switching element SW1 connected to the first ceramic heater 111 and the duty cycle DR2 of the second switching element SW2 connected to the second ceramic heater 112 are set to a value other than 0% or 100%, the other duty cycle DR1 of the first switching element SW1 and the duty cycle DR2 of the second switching element SW2 are maintained at 0% or 100%. In other words, during periods when one of the first switching element SW1 and the second switching element SW2 is switching, the other of the first switching element and the second switching element are maintained at either the off or on state. This has the following significance.

[0063] If the duty cycles of the first switching element SW1 and the second switching element SW2 are not 0% or 100%, the heater controller HC inputs to the first switching element SW1 and the second switching element SW2 a signal in which the ratio of pulse width to period is not 0% or 100%, i.e., a pulse signal having rising and falling edges as shown in Figures 7(b) to 7(d).

[0064] When PWM signals SG1 and SG2, which are pulse signals having rising and falling edges, are input to the first switching element SW1 and the second switching element SW2, they turn ON in the region where the pulse signal is ON, electrically connecting the power supply PS and the heat-generating parts H1 and H2. On the other hand, when the pulse signal is OFF, the first switching element SW1 and the second switching element SW2 turn OFF, electrically disconnecting the power supply PS and the heat-generating parts H1 and H2. In other words, high-speed switching (i.e., switching) between the ON state and the OFF state is performed in the first switching element SW1 and the second switching element SW2.

[0065] When switching occurs in the first switching element SW1 and the second switching element SW2, noise (electrical noise) is generated due to the electrical changes (mainly changes in current) caused by the switching. The magnitude of this noise increases in proportion to the magnitude of the electrical changes corresponding to the switching.

[0066] On the other hand, when the duty cycle of the first switching element SW1 and the second switching element SW2 is 0% or 100%, the heater controller HC inputs a signal to the first switching element SW1 and the second switching element SW2 that has a pulse width ratio of 0% or 100% to the period, i.e., a constant signal as shown in Figures 7(a) and 7(e). In this case, the first switching element SW1 and the second switching element SW2 are always off when the constant signal shown in Figure 7(a) is input, and always on when the constant signal shown in Figure 7(e) is input, and no noise is generated.

[0067] In this embodiment, the heating device 10 connects a first ceramic heater 111 and a second ceramic heater 112 in parallel to a single power supply PS. Therefore, the current flowing from the power supply PS to the first ceramic heater 111 and the current flowing from the power supply PS to the second ceramic heater 112 can be made relatively small. For example, when a single power supply with an output voltage of 100[V] is connected to a single ceramic heater and 1[kW] of power is supplied to the ceramic heater, the current flowing from the power supply to the ceramic heater is 10[A]. In contrast, when two ceramic heaters are connected to a single power supply with an output voltage of 100[V] as in this embodiment, and a total of 1[kW] of power is supplied to the two ceramic heaters, the current flowing from the power supply to each ceramic heater is, for example, 5[A].

[0068] In this embodiment, during the period in which one of the first switching element SW1 and the second switching element SW2 is switching, the other of the first and second switching elements is kept in an off or on state. That is, during the period in which noise due to switching is generated in one of the first switching element SW1 and the second switching element SW2, the other of the first switching element SW1 and the second switching element SW2 is kept in a state in which no noise due to switching is generated.

[0069] Thus, in this embodiment, the controller HC and heating device 10 have relatively small currents flowing from the power supply PS to the ceramic heater 111 via the switching element SW1, and from the power supply PS to the ceramic heater 112 via the switching element SW2. Furthermore, during the period when one of the first switching element SW1 and the second switching element SW2 is switching, the other of the first and second switching elements is kept in an off or on state, thereby preventing the generation of noise due to switching. Consequently, the electrical changes associated with switching are small, and the noise generated is also small.

[0070] The advantageous effects of the heater controller HC and heating device 10 of this embodiment are summarized below.

[0071] In this embodiment, the heater controller HC and heating device 10, in the heater section HP which applies the output voltage from a single power supply PS to the first ceramic heater 111 and the second ceramic heater 112 in parallel, maintains the other of the first and second switching elements in an off or on state during the period in which one of the first switching element SW1 between the power supply PS and the first ceramic heater 111 and the second switching element SW2 between the power supply PS and the second ceramic heater 112 is switched. Therefore, electrical changes associated with switching can be reduced, and the generation of electrical noise associated with the control of the ceramic heater 11 can be suppressed. This ability to suppress noise generation is particularly advantageous when using the heater controller HC and heating device 10 of this embodiment in electric vehicles where strict standards for noise generation are set.

[0072] In this embodiment, the heater controller HC and heating device 10 are controlled by the applied voltage V determined in the PI control step S2. A The voltage range is 0V to 0.5V. MAX During the period when the voltage is [V] (first period), the second switching element SW2 is kept off and the first switching element SW1 is switched, and the applied voltage V determined in the PI control process S2 is used. A 0.5VMAX [V] to V MAX During the period when [V] is (the second period), the first switching element SW1 is maintained in the on state and the second switching element SW2 is switched. Thus, by changing the switching element that performs switching according to the period, it is possible to suppress the progress of deterioration of the switching element due to switching to only one of the first switching element SW1 and the second switching element SW2.

[0073] The heater controller HC and the heating device 10 of the present embodiment apply the voltage V determined in the PI control step S2 A is 0 [V] to 0.5 V MAX From the period when [V] is (the first period), the voltage V determined in the PI control step S2 A is 0.5 V MAX [V] to V MAX When shifting to the period when [V] is (the second period), first, the PWM signal SG1 input to the first switching element SW1 is set as a constant signal shown in FIG. 7(e) to maintain the first switching element SW1 in the on state, and then the PWM signal SG2 input to the second switching element SW2 is changed from the constant signal shown in FIG. 7(a) to start switching of the second switching element SW2. Therefore, it is possible to prevent the switching of the first switching element SW1 and the switching of the second switching element SW2 from being performed simultaneously, and thus to prevent the noise from the heater unit HP from increasing.

[0074] (Modified Example) In the above embodiment, the following modification can also be used.

[0075] In the above embodiment, the heater unit HP of the heating device 10 has a ceramic heater 11 in which a first ceramic heater 111 and a second ceramic heater 112, each of which is cylindrical, are coaxially connected. However, it is not limited to this. The heater unit HP can use any heater having an arbitrary configuration as a heating unit for heating the object to be heated.

[0076] Specifically, for example, as shown in Figure 8(a), the ceramic heater 11 may have a configuration in which two separate heating elements H1 and H2 are positioned side by side in the axial direction of the ceramic cylinder CC inside a single ceramic cylinder CC. Note that although heating element H1 is depicted as two heating elements H1 in Figure 8(a), these are a series and the power supply is controlled as a whole. The same applies to heating element H2. Alternatively, as shown in Figure 8(b), the ceramic heater 11 may have a configuration in which two separate heating elements H1 and H2 are positioned side by side in the circumferential direction of the ceramic cylinder CC inside a single ceramic cylinder CC. Or, as shown in Figure 8(c), the ceramic heater 11 may have a configuration in which two separate heating elements H1 and H2 are positioned inside a flat ceramic plate CP.

[0077] Instead of a ceramic heater, any other heater, such as a sheath heater, may be used.

[0078] In this invention, the phrase "multiple heating units" means multiple heating units that can independently control their output (control of supplied power). Therefore, the "multiple heating units" of this invention include not only multiple heaters that are independent of each other, but also multiple heating elements that are separately provided within a single heater and whose output is independently controlled. Furthermore, in this invention, "heating the same object to be heated" includes not only the case in which multiple heating units heat the same or a single object to be heated, but also the case in which a first object to be heated by a first heating unit among the multiple heating units and a second object to be heated by a second heating unit among the multiple heating units are thermally integrated (i.e., a case in which heat exchange is possible between the first object to be heated and the second object to be heated). As an example, a fluid (liquid) that flows through a channel in which the first heating unit is located and is heated by the first heating unit, and also flows through a channel in which the second heating unit is located and is heated by the second heating unit, falls under the category of "the same object to be heated".

[0079] In the above embodiment, the heater section HP of the heating device 10 has two heaters, namely a first ceramic heater 111 and a second ceramic heater 112, whose power supply amounts are controlled independently of each other. However, it is not limited to this. The number of heaters (heating sections, heating elements) in the heater section HP whose power supply amounts are controlled independently of each other may be three or more, or any number of such heaters.

[0080] Specifically, for example, the ceramic heater 11 may be configured in which a first ceramic heater 111, a second ceramic heater 112, and a third ceramic heater 113, each being cylindrical, are coaxially connected (Figure 9). The third ceramic heater 113 has a cylindrical ceramic tube (not shown) and a heating element H3 placed inside the ceramic tube. The power supply circuit 13, as shown in Figure 9, has a power supply PS, a first switching element SW1, a second switching element SW2, and a third switching element SW3. The third switching element SW3 is an element that is switched by PWM control by a heater controller HC, similar to the first switching element SW1 and the second switching element SW2.

[0081] In this embodiment, during the duty cycle determination step S3, the heater controller HC may maintain at least one of the first switching element SW1, second switching element SW2, and third switching element SW3 in an ON or OFF state during the period in which at least one of the first switching element SW1, second switching element SW2, and third switching element SW3 is switched. Alternatively, during the period in which any one of the first switching element SW1, second switching element SW2, and third switching element SW3 is switched, the remaining two of the first switching element SW1, second switching element SW2, and third switching element SW3 may be maintained in an ON or OFF state.

[0082] By increasing the number of switching elements connected in parallel to a power supply, the current flowing through the switching elements to the heating element can be reduced, thereby reducing the noise generated by the switching of those elements. Furthermore, the fewer the number of switching elements that switch simultaneously, the less noise can be generated. The noise can be minimized by keeping all other switching elements either on or off when one switching element is being switched.

[0083] In the heater section HP of the heating device 10 of the above embodiment, a single ceramic heater 111 is connected to the first switching element SW1, and a single ceramic heater 112 is connected to the second switching element SW2. However, it is not limited to this, and the number of heating elements (heating components) connected to a single switching element is arbitrary.

[0084] Specifically, for example, as shown in Figure 10, the first switching element SW1 may be connected to two separate heating elements H11 and H12, and the second switching element SW2 may be connected to two separate heating elements H21 and H22. Heating elements H11 and H12 may be placed inside a single ceramic member, or they may be placed inside different ceramic members. The same applies to heating elements H21 and H22.

[0085] In the above embodiment, the applied voltage V that the heater controller HC performs in the duty cycle determination step S3 A The determination of duty cycles DR1 and DR2 based on this may be in any manner in which the other of the first switching element SW1 and the second switching element SW2 is kept in an off state or an on state during the period in which one of the first switching element SW1 and the second switching element SW2 is switched.

[0086] Specifically, for example, the configuration shown in Figure 6(b) is possible. In the configuration shown in Figure 6(b), the applied voltage V determined in the PI control process S2 is... A The voltage range is 0V to 0.5V.MAX If [V], the configuration is the same as shown in Figure 6(a). On the other hand, the heater controller HC uses the applied voltage V determined in the PI control process S2. A 0.5V MAX [V] ~V MAX If [V], the applied voltage V should be applied to the heating element H2 of the second ceramic heater 112. A2 0.5V MAX [V] is determined to be the applied voltage V to be applied to the heating element H1 of the first ceramic heater 111. A1 The applied voltage V A From the applied voltage V A2 (That is, 0.5V) MAX The value obtained by subtracting (i.e., 0[V]~0.5V) MAX Determine the applied voltage (one of the values ​​of [V]). Then, the applied voltage V A2 0.5V MAX Based on the determination that [V], the duty cycle DR2 was determined to be 100[%], and the applied voltage V A1 0[V]~0.5V MAX Based on the determination of one of the values ​​of [V], the duty cycle DR1 is set to the corresponding value between 0[%] and 100[%].

[0087] In the above embodiment, one of the first switching element SW1 and the second switching element SW2 may be an analog switch that does not perform high-speed switching. For example, when the second switching element SW2 is an analog switch, in the duty cycle determination step S3 the heater controller HC uses the applied voltage V determined in the PI control step S2. A The voltage range is 0V to 0.5V. MAX If [V], the second switching element SW2 is turned off, and the applied voltage V should be applied to the heating element H1 of the first ceramic heater 111. A1 The applied voltage V A The value is set to be equal to . The heater controller HC applies the voltage V determined in the PI control process S2. A 0.5V MAX [V] ~V MAX If [V], the second switching element SW2 is turned ON, and the applied voltage V should be applied to the heating element H1 of the first ceramic heater 111.A1 The applied voltage V A From the applied voltage V A2 (That is, 0.5V) MAX This value is obtained by subtracting ).

[0088] In the above embodiment, the heater controller HC applies the voltage V in the duty cycle determination step S3. A The method of determining the duty cycles DR1 and DR2 based on this may be switched periodically or irregularly.

[0089] Specifically, for example, the heater controller HC determines the duty cycles DR1 and DR2 in the manner of the above embodiment during the first period, and determines the duty cycles DR1 and DR2 in the manner shown in Figure 6(c) during the second period, which is different from the first period. In the manner shown in Figure 6(c), the values ​​of duty cycles DR1 and DR2 are completely swapped compared to the manner shown in Figure 6(a). In other words, in the manner shown in Figure 6(c), the control that was performed on the first switching element SW1 in the manner shown in Figure 6(a) is performed on the second switching element SW2, and the control that was performed on the second switching element SW2 in the manner shown in Figure 6(a) is performed on the first switching element SW1.

[0090] In the above embodiment, the decision of whether to perform switching in the first switching element SW1 or the second switching element SW2 depends on the supply voltage V A It can be switched according to the value of (i.e., the supply voltage V A The voltage range is 0V to 0.5V. MAX In the case of [V], the first switching element SW1 is switched, and the supply voltage VA is 0.5V MAX [V] ~V MAX (In the case of [V], the second switching element SW2 is switched). Therefore, degradation due to switching is suppressed in only one of the first switching element SW1 and the second switching element SW2. In this modified example, the manner in which the duty cycles DR1 and DR2 are determined is further changed to the supply voltage V A By switching periodically or irregularly without being based on the value of, for example, the supply voltage VA Even when the value of converges to a predetermined value, the deterioration due to switching is suppressed in only one of the first switching element SW1 and the second switching element SW2. In this case as well, when transitioning from the first period to the second period, one of the first switching element SW1 and the second switching element SW2 may be kept off or on before switching of the other of the first switching element SW1 and the second switching element SW2 is started.

[0091] In the above embodiment, the heater controller HC takes the outlet liquid temperature T as the input for PI control in the PI control process S2. OUT Target value TT OUT and the current outlet liquid temperature T OUT The temperature difference ΔT between the two is used, but is not limited to this. As input to the PI control, a value based on the measurement value of the second temperature sensor, a value indicating the temperature of the ceramic heater 11 itself detected by a temperature sensor not shown, etc., may be used. In the present invention, "temperature information indicating the temperature of the object to be heated" includes not only temperature information indicating the temperature of the object to be heated itself, but also temperature information indicating the temperature of the heating element that heats the object to be heated (i.e., temperature information that indirectly indicates the temperature of the object to be heated). In addition, the heater controller HC may determine the power supplied to the ceramic heater 11 by arbitrary feedback control instead of PI control.

[0092] In the above embodiment, the heater controller HC may control the power supplied to the first ceramic heater 111 and the second ceramic heater 112 by controlling the first switching element SW1 and the second switching element SW2 using a control method different from PWM control. Specifically, for example, PFM control may be used. In this case as well, the generation of noise associated with switching can be suppressed, similar to the above embodiment.

[0093] In the above embodiment, the first switching element SW1 (and heating element H1) and the second switching element SW2 (and heating element H2) are connected in parallel to a single power supply PS, but this is not limited to this configuration. For example, the first switching element SW1 (and heating element H1) may be connected to a first power supply, and the second switching element SW2 (and heating element H2) may be connected to a second power supply different from the first power supply.

[0094] In the above embodiment, the heater controller HC and heating device 10 were described as being used as part of a heating system 100 installed inside an electric vehicle to provide heat to the vehicle's interior. However, the heater controller HC and heating device 10 can be used with any device or system other than the heating system 100.

[0095] Specifically, for example, in an electric vehicle, the heater controller HC and heating device 10 can be used as part of a battery heating system for keeping the battery warm. The battery heating system has a configuration in which, for example, the heat dissipation section 20 of the heating system 100 is replaced with a conduit that contacts the battery and surrounds the battery.

[0096] In the above embodiments and modifications, the heating device 10 heats the liquid L, and the heat radiated from the liquid L is used to ultimately transfer heat to the object that requires heat (vehicle interior, battery, etc.). However, this is not the only option. For example, the ceramic heater 11 of the heating device 10 may be brought close to or in contact with the object that ultimately requires heat, thereby transferring heat to the object (an example of the "object to be heated") without using the liquid L.

[0097] In the above embodiment, the heater controller HC and heating device 10 were described as being used in an electric vehicle. However, the heater controller HC and heating device 10 may be used in any automobile, transportation equipment, or device other than an electric vehicle.

[0098] As long as the features of the present invention are maintained, the present invention is not limited to the embodiments described above, and other forms conceivable within the scope of the technical idea of ​​the present invention are also included within the scope of the present invention.

[0099] (Note) Those skilled in the art will understand that the above embodiments and their modifications are specific examples of the following embodiments.

[0100] (Item 1) Heater control heater controller, The aforementioned heater is Multiple heating sections, including a first heating section and a second heating section, A first switching element connected to the first heating section, It has a second switching element connected to the second heating section, The aforementioned heater controller is The power supplied to the plurality of heating units is controlled by controlling each of the first switching element and the second switching element. A heater controller that maintains the other of the first and second switching elements in the off or on state during the period in which one of the first and second switching elements is switched.

[0101] (Item 2) During the first period, the first switching element is switched, and the second switching element is kept off or on. The heater controller according to item 1, wherein in a second period different from the first period, the second switching element is switched and the first switching element is kept off or on.

[0102] (Item 3) The heater controller according to item 2, which, when transitioning from the first period to the second period, maintains the first switching element in the off or on state and then starts switching the second switching element.

[0103] (Item 4) Each of the first switching element and the second switching element is controlled by PWM, A heater controller according to any one of items 1 to 3, which changes the duty cycle of the first switching element and / or the second switching element by feedback control based on temperature information indicating the temperature of the object to be heated.

[0104] (Item 5) The plurality of heating units include at least three heating units, including the first heating unit, the second heating unit, and the third heating unit. The heater further includes a third switching element connected to the third heating section. The aforementioned heater controller is The power supplied to the plurality of heating units is controlled by controlling each of the first switching element, the second switching element, and the third switching element. A heater controller according to any one of items 1 to 4, wherein at least one of the first switching element, the second switching element, and the third switching element is kept on or off during the period in which at least one of the first switching element, the second switching element, and the third switching element is switched.

[0105] (Item 6) The heater controller according to item 5, which maintains the remaining two of the first, second, and third switching elements on or off during the period in which any one of the first, second, and third switching elements is switched.

[0106] (Item 7) A heater controller according to any one of items 1 to 6, wherein the object to be heated is a liquid.

[0107] (Item 8) The heater controller described in any one of items 1 to 7, wherein the aforementioned multiple heaters are heaters used in electric vehicles.

[0108] (Item 9) Multiple heating sections, including a first heating section and a second heating section, A first switching element connected to the first heating section, A second switching element connected to the second heating section, A heater equipped with, A heater controller listed in any one of items 1-8, A heating device equipped with the following features.

[0109] (Item 10) A heater control method, The aforementioned heater is Multiple heating sections, including a first heating section and a second heating section, A first switching element connected to the first heating section, It has a second switching element connected to the second heating section, The power supplied to the plurality of heating units is controlled by controlling each of the first switching element and the second switching element, A heater control method comprising keeping the other of the first switching element and the second switching element on or off during the period in which one of the first switching element and the second switching element is switched. [Explanation of Symbols]

[0110] 10: Heating device, 11: Ceramic heater, 12: Housing, 13: Power supply circuit, 20: Heat dissipation section, 31: First flow path, 32: Second flow path, 41: First thermometer, 42: Second thermometer, 50: Flow meter, 111: First ceramic heater, 112: Second ceramic heater, H1, H2, H3: Heating elements, HC: Heater controller, HP: Heater section, PS: Power supply, SG1, SG2: PWM signal, SW1: First switching element, SW2: Second switching element, SW3: Third switching element

Claims

1. Heater control heater controller, The aforementioned heater is A plurality of heating units, including a first heating unit and a second heating unit, A first switching element connected to the first heating section, It has a second switching element connected to the second heating section, The aforementioned heater controller is The power supplied to the plurality of heating units is controlled by controlling each of the first switching element and the second switching element. A heater controller that maintains the other of the first and second switching elements in the off or on state during the period in which one of the first and second switching elements is switched.

2. During the first period, the first switching element is switched, and the second switching element is kept off or on. The heater controller according to claim 1, wherein in a second period different from the first period, the second switching element is switched and the first switching element is kept off or on.

3. The heater controller according to claim 2, wherein when transitioning from the first period to the second period, the first switching element is kept off or on before starting the switching of the second switching element.

4. Each of the first switching element and the second switching element is controlled by PWM, The heater controller according to claim 1, wherein the duty cycle of the first switching element and / or the second switching element is changed by feedback control based on temperature information indicating the temperature of the object to be heated.

5. The plurality of heating units consist of at least three heating units, including the first heating unit, the second heating unit, and the third heating unit. The heater further includes a third switching element connected to the third heating section. The aforementioned heater controller is The power supplied to the plurality of heating units is controlled by controlling each of the first switching element, the second switching element, and the third switching element. The heater controller according to claim 1, wherein at least one of the first switching element, the second switching element, and the third switching element is kept on or off during the period in which at least one of the first switching element, the second switching element, and the third switching element is switched.

6. The heater controller according to claim 5, wherein during the period in which any one of the first switching element, the second switching element, and the third switching element is switched, the remaining two of the first switching element, the second switching element, and the third switching element are kept on or off.

7. The heater controller according to claim 1, wherein the object to be heated is a liquid.

8. The heater controller according to any one of claims 1 to 7, wherein the plurality of heaters are heaters used in an electric vehicle.

9. A plurality of heating units, including a first heating unit and a second heating unit, A first switching element connected to the first heating section, A second switching element connected to the second heating section, A heater equipped with, A heater controller according to any one of claims 1 to 7, A heating device equipped with the following features.

10. A heater control method, The aforementioned heater is A plurality of heating units, including a first heating unit and a second heating unit, A first switching element connected to the first heating section, It has a second switching element connected to the second heating section, The power supplied to the plurality of heating units is controlled by controlling each of the first switching element and the second switching element, A heater control method comprising keeping the other of the first switching element and the second switching element on or off during the period in which one of the first switching element and the second switching element is switched.

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