ENERGY TRANSMISSION IN A LINEAR TRANSPORT SYSTEM

Description

[0001] The invention relates to a method for transmitting energy from a stationary unit of a linear transport system to a movable unit of a linear transport system and to a linear transport system.

[0002] Linear transport systems are known from the prior art in which a movable unit can be moved along a guide rail and which have a linear motor for driving the movable unit. The linear motor comprises a stator and a rotor. The stator can have at least one motor module arranged stationary along the guide rail with one or more drive coils, while the movable unit is arranged on a carriage and can have one or more magnets. By energizing the drive coils, a force can be generated on the magnets of the movable unit such that the movable unit moves along the guide rail. It can also be provided that the movable unit or the carriage has a tool, wherein energy must be transferred from the stationary unit to the movable unit to operate the tool.Furthermore, it may be necessary to transmit data both from the stationary unit to the movable unit and from the movable unit to the stationary unit. DE 10 2018 111 715 A1 discloses the features of the preamble of the independent claims and describes such a linear transport system with an energy transfer between a stationary coil module, i.e., a stationary unit, and a movable carriage, i.e., a movable unit. DE 10 2020 107 782 A1 likewise discloses an energy transfer in a linear transport system in which energy transmitting coils are selected based on a position of the movable unit and an energy receiving coil arranged on the movable unit, and are energized based on an energy quantity signal. WO 2018 / 221532 A1 and WO 2005 / 021317 A1 each disclose methods for wirelessly transmitting energy from a stationary unit to a movable unit.

[0003] One object of the present invention is to provide an improved method for transferring energy from a stationary unit to a moving unit of a linear transport system. A further object of the invention is to provide a linear transport system in which such an energy transfer is possible.

[0004] These objects are achieved by the method and the linear transport system of the independent patent claims. Advantageous embodiments are specified in the dependent patent claims.

[0005] A linear transport system comprises a guide rail for guiding a moving unit, several stationary units, and a linear motor for driving the moving unit along the guide rail. The linear motor has a stator and a rotor, the stator comprising the stationary units, each of which has one or more drive coils. The rotor is arranged on the moving unit and has one or more magnets, the stationary units each comprising one or more energy transmitting coils, each energy transmitting coil having control electronics. The moving unit has at least one energy receiving coil. To transfer energy from the stationary unit to the moving unit of the linear transport system, the control electronics of the energy transmitting coils carry out the steps described below. An energy quantity signal for the respective energy transmitting coil is read in.The energy quantity signal is then converted into a pulse-to-pause ratio, and the energy transmitting coil is controlled based on the pulse-to-pause ratio. Control can also include closed-loop control, so that the current through the energy transmitting coil can be regulated based on the energy quantity signal and the counter.

[0006] In principle, it is also conceivable to use the described method to transfer energy from the moving unit to the stationary unit, with the energy receiving coil then transmitting the energy and the energy transmitting coil receiving the energy.

[0007] In one embodiment, the energy quantity signal is converted into the pulse-to-pause ratio using a counter. The pulse-to-pause ratio is used to control the current flowing through the energy transmitting coil.

[0008] In this case, it can be provided that the energy quantity signal is linked to a meter value and, for example, a switch linked to the energy transmitting coil is switched on for certain meter values ​​and off for other meter values. The energy quantity signal can determine which meter values ​​the switch is switched on or off for. This method enables simple control of the energy transmitting coil.

[0009] For example, the switch can be switched on whenever the counter is above a counter value calculated from the energy quantity signal.

[0010] In one embodiment, the control electronics of the energy transmission coil have at least a first half-bridge with a first switch and a second switch, and a second half-bridge with a third switch and a fourth switch. The energy transmission coil is arranged between a first half-bridge center point and a second half-bridge center point, wherein the first half-bridge center point is arranged between the first switch and the second switch, and the second half-bridge center point is arranged between the third switch and the fourth switch. Provision can be made for the first switch and the third switch to be connected to a first terminal of a voltage source, and for the second switch and the fourth switch to be connected to a second terminal of a voltage source. The counter counts upwards from a minimum value to a maximum value and then downwards from the maximum value to the minimum value.This counting process can then be repeated, with the counting increasing to the maximum upon reaching the minimum and then decreasing from the maximum again. The energy quantity signal is linked to an upper counter value and a lower counter value. The first switch and the fourth switch are switched on when the counter is above the upper counter value, and the second switch and the third switch are switched on when the counter is below the lower counter value.

[0011] Thanks to the half-bridges and the counting method, the energy transmitting coil can be supplied with current in a first direction when the counter is above the upper counter value, and with current in a direction opposite to the first direction when the counter is below the lower counter value. This enables improved control of the energy transmitting coils.

[0012] In one embodiment, a nominal power is to be transmitted. In this case, the upper counter value is greater than three-quarters of the difference between the maximum value and the minimum value, plus the minimum value. The lower counter value is less than one-quarter of the difference between the maximum value and the minimum value, plus the minimum value.

[0013] Thus, if the rated power is to be transmitted, this method ensures that the energy transmitting coil is operated in the first current flow direction for less than a quarter of the meter's operating time, then the coil is not energized for more than a quarter of the meter's operating time, then the energy transmitting coil is operated in the second current flow direction for less than a quarter of the meter's operating time, and then the energy transmitting coil is not energized for more than a quarter of the meter's operating time. This enables efficient control.

[0014] In one embodiment, for transmitting the rated power, the upper counter value is at least seven-eighths of the difference between the maximum and minimum values, plus the minimum value, and the lower counter value is at most one-eighth of the difference between the maximum and minimum values, plus the minimum value. This allows for a reduction in thermal load during power transmission, as the power transmission coil is energized for a shorter period of time.

[0015] In one embodiment, for transmitting a peak power exceeding the rated power, the upper counter value is at least three-quarters of the difference between the maximum value and the minimum value plus the minimum value and the lower counter value is at most one-quarter of the difference between the maximum value and the minimum value plus the minimum value.

[0016] The peak power can be transmitted particularly when large amounts of energy are required at the moving unit. In particular, it can be provided that the peak power is not transmitted continuously, but only for predetermined periods of time, and then the transmission power is reduced again to prevent thermal load on the energy transmission coil or the control electronics. This can be the case, in particular, if, for the transmission of the nominal power, the upper counter value is at least seven-eighths of the difference between the maximum value and the minimum value plus the minimum value, and the lower counter value is at most one-eighth of the difference between the maximum value and the minimum value plus the minimum value.

[0017] If the minimum value is zero, the underlying equations can be simplified.

[0018] In one embodiment, a data transmission signal is also read in by the control electronics. The data transmission signal indicates that data transmission is taking place in the area of ​​the energy transmission coil. In this case, the first switch and the fourth switch are switched off at least once when the counter is above the upper counter value, and the second switch and the third switch are switched off at least once when the counter is below the lower counter value. This is particularly useful when data transmission could be disrupted by the transmission of energy and the security of the data transmission takes priority over the transmitted energy. The subsequent deactivation of the energy transmission coils can improve the quality of the data transmission.

[0019] In one embodiment of the method, a control unit additionally outputs a synchronization signal to the control electronics of the energy transmission coils. The control electronics synchronize the counters based on the synchronization signal. This allows for the energy transmission to be synchronized accordingly with different energy transmission coils. This can be done, for example, using a PLL in each control electronics.

[0020] In one embodiment of the method, a control unit determines position data of the energy receiving coil of the movable unit and selects at least one energy transmitting coil within the linear transport system based on the position data of the energy receiving coil. An energy quantity signal is then output to the control electronics of the selected energy transmitting coils. This makes it possible to control the energization of the energy transmitting coils such that energization is only applied to energy transmitting coils where movable units, and thus energy receiving coils, can also be located.

[0021] In one embodiment of the method, the position data of the energy receiving coil of the movable unit result in the energy receiving coil moving from a first energy transmitting coil to a second energy transmitting coil. First control electronics of the first energy transmitting coil and second control electronics of the second energy transmitting coil are each synchronized using the synchronization signal. A first counter of the first control electronics and a second counter of the second control electronics are started simultaneously using the synchronization signal. The energy quantity signal is output to the first control electronics and the second control electronics, with the control electronics linking the energy quantity signal to an upper counter value and a lower counter value.The first switch and the fourth switch of the first control electronics are switched on when the counter is above the upper counter value. The second switch and the third switch of the first control electronics are switched on when the counter is below the lower counter value. The first switch and the fourth switch of the second control electronics are switched on when the counter is above the upper counter value, and the second switch and the third switch of the second control electronics are switched on when the counter is below the lower counter value. This enables synchronous operation of the first energy transmission coil and the second energy transmission coil, so that the movable unit can be moved from the first energy transmission coil to the second energy transmission coil with as little interference as possible.

[0022] In one embodiment, the position data indicates that the energy receiving coil is arranged between the first energy transmitting coil and the second energy transmitting coil. In this case, the upper counter value is reduced and the lower counter value is increased. If the energy receiving coil is arranged between the first energy transmitting coil and the second energy transmitting coil, there is no ideal coupling between the energy transmitting coils and the energy receiving coil. By reducing the upper counter value and increasing the lower counter value, the amount of energy transmitted via the energy transmitting coils is increased, so that the reduced coupling can be compensated. This can be done in particular such that the movable unit moves from the first energy transmitting coil to the second energy transmitting coil and the energy receiving coil receives a constant amount of energy.This means in particular that for the energy receiving coil it is not possible to distinguish whether the energy receiving coil was coupled to one energy transmitting coil or to two energy transmitting coils during the entire energy transfer and whether the energy was transmitted via one energy transmitting coil or via two energy transmitting coils.

[0023] In one embodiment, if a power greater than the rated power is to be transmitted, a thermal load on the energy transmission system is additionally determined. A cooling time is also calculated. A further reduction of the upper counter value and a further increase of the lower counter value such that a power greater than the rated power can be transmitted only occurs after the cooling time. This makes it possible to avoid thermal load on the energy transmission system or the energy transmission coils and drive electronics.

[0024] In one embodiment, the current supply to the drive coils is changed such that the movable unit moves faster. This makes it possible, particularly when the amount of energy transmitted needs to be increased due to the movement of the energy receiving coil from the first energy transmitting coil to the second energy transmitting coil, to move the movable unit faster in this area, thereby reducing the duration of the increased energy transmission. If the movable unit, and thus the energy receiving coil, is arranged exclusively in the area of ​​the first energy transmitting coil or exclusively in the area of ​​the second energy transmitting coil, a drive current can also be reduced accordingly in order to maintain a predetermined average speed of the movable unit overall.

[0025] In one embodiment, an increase period during which the current supply to the drive coil is changed is calculated from a speed of the moving unit. The increase period is therefore the time during which the moving unit is moved faster.

[0026] In one embodiment, the upper counter value and the lower counter value are adjusted based on a temperature measured in the area of ​​the energy transmission coil. This can be used, in particular, to prevent thermal overload of the energy transmission coil or the drive electronics. If the measured temperature is above a critical temperature, the upper counter value can be increased and the lower counter value can be reduced, so that the amount of energy transmitted decreases while thermal stress on the energy transmission coil and the drive electronics is avoided.

[0027] The invention further comprises a linear transport system with at least one stationary unit and at least one movable unit, as well as a control unit. The linear transport system has a guide rail for guiding the movable unit, a plurality of stationary units, and a linear motor for driving the movable unit along the guide rail. The linear motor comprises a stator and a rotor. The stator comprises the stationary units, each of which comprises one or more drive coils. The rotor is arranged on the movable unit and comprises one or more magnets. The stationary units each comprise one or more energy transmitting coils. Each energy transmitting coil is assigned control electronics. The movable unit comprises at least one energy receiving coil.The control electronics are configured to read in an energy quantity signal for the respective energy transmission coil, in particular to read in an energy quantity signal transmitted by the control unit, to convert it into a pulse-pause ratio and to control the energy transmission pulses based on the pulse-pause ratio.

[0028] In one embodiment, the control electronics are configured to convert the energy quantity signal into a pulse-pause ratio by means of a counter, wherein a current through the energy transmitting coil is controlled based on the pulse-pause ratio.

[0029] In one embodiment, the movable unit of the linear transport system comprises a smoothing capacitor,

[0030] The invention further comprises the control electronics and control units which are designed to carry out the method according to the invention and, in addition, computer programs for carrying out the method.

[0031] The invention will be explained in more detail below using exemplary embodiments and with reference to the figures, each of which shows a schematic representation Fig. 1a linear transport system; Fig. 2a side view of a section of the linear transport system of the Fig. 1 ; Fig. 3 a circuit diagram for controlling energy transmission coils; Fig. 4 a data transmission for controlling; Fig. 5 a control electronics; Fig. 6 a first control of an energy transmission coil; Fig. 7 a second control of an energy transmission coil; Fig. 8 a temperature profile diagram; Fig. 9 a stationary unit and a movable unit of a linear transport system; Fig. 10 an electrical circuit of a movable unit; and Fig. 11 a third control of an energy transmission coil.

[0032] In the following, the same reference symbols may be used for identical features. Furthermore, for reasons of clarity, not all elements may be shown in every figure. Furthermore, for reasons of clarity, not every element in every drawing may be provided with its own reference symbol.

[0033] Fig. 1 shows a section of a linear transport system 101. The linear transport system 101 comprises a movable unit 103, which is guided by a guide rail 105. The movable unit 103 comprises rollers (not shown here) and a runner 113 with magnets (not shown). The rollers of the movable unit 103 can roll on running surfaces of the guide rail 105.

[0034] The linear transport system 101 further comprises a linear motor 107, wherein the linear motor 107 has a stator 109. The stator 109 of the linear motor 107 is arranged in the stationary units 111, which each have a plurality of drive coils 135 for this purpose. The stationary units 111 are in Fig. 1 partially designed differently, whereby individual stationary units 111 can be straight or curved. The linear motor 107 further comprises the rotor 113, which is arranged on the movable unit 103 and comprises one or more magnets. The stationary units 111 each comprise an energy transmitting coil 125. The movable unit 103 comprises an energy receiving coil 127. In a Fig. 1 In an alternative embodiment not shown, a stationary unit 111 can also comprise a plurality of energy transmission coils 125. The stationary units 111 and the guide rail 105 can be arranged circumferentially so that the movable unit 103 can be moved along a closed path.

[0035] Each stationary unit 111 further comprises control electronics 123, with which a current flowing through the energy transmission coil 125 can be controlled. The linear transport system 101 further comprises a control unit 133, which is directly connected to one of the stationary units 111. A data signal from the control unit 133 can be forwarded from one stationary unit 111 to the next stationary unit 111. Alternatively, not in Fig. 1 As shown, embodiments are also conceivable in which the control unit 133 is directly connected to each stationary unit 111 or to a subset of the stationary units 111. The control electronics 123 of the stationary units 111 can, in particular, receive data signals from the control unit 133 and, based on these control signals, control the energy transmission coils 125.

[0036] The stationary units 111 further comprise optional stationary antennas 129. The movable unit 103 comprises an optional movable antenna 131. The movable antenna 131 is fixed to the movable unit 103 and can therefore move along the guide rail 105 together with the movable unit 103. Data can be exchanged between the stationary units 111 and the movable unit 103 using the stationary antennas 129 and the movable antenna 131. Alternatively, such data transmission can also be implemented, for example, using a wireless WLAN or Bluetooth connection or an infrared connection or a 5G connection or according to the DECT standard or as an optical transmission.

[0037] Fig. 2 shows a side view of a stationary unit 111 including a guide rail 105, on which a movable unit 103 is arranged. The guidance of the movable unit 103 can also be achieved by means of alternative, not shown, configurations. Rollers 139 of the movable unit 103 can roll on running surfaces 141 of the guide rail 105, thus enabling a substantially one-dimensional movement of the movable unit 103 along the guide rail 105. Also shown in Fig. 2 Magnets 117 of the movable unit 103 are shown, which form the rotor 113 of the linear motor 107. Furthermore, the drive coils 135 are shown in the area of ​​the stator 109. In contrast to the illustration of the Fig. 2 It can also be provided that the magnets 117 are arranged only on one side of the drive coil 135. Below the magnets 117 and the stator 109, the movable unit 103 has a position detection element 143 on one side. The stationary unit 111 has a position sensor 145 in this area. The position sensor 145 can, for example, measure a changed induction behavior of a coil caused by a piece of metal embedded in the position detection element 143. For this purpose, the position sensor 145 can, for example, have an energized coil in which a changed inductance, caused by a passing position detection element 143, leads to a change in the current in the coil, thus allowing the position of the position detection element 143 and thus of the movable unit 103 to be detected.Of course, the position sensor 145 can also be designed differently, for example, with an excitation and receiving coil, each of which can also measure the inductance of the metal piece embedded in the position detection element 143. Furthermore, magnets embedded in the position detection element 143 or a light barrier evaluation for position determination are also conceivable.

[0038] Fig. 3 shows data communication within a linear transport system 101. Three stationary units 111 are schematically shown, each stationary unit 111 having a control electronics unit 123 and an energy transmission coil 125. The control electronics unit 123 serves to control the energy transmission coil 125. It can be provided that each stationary unit 111 is assigned more than one control electronics unit 123 and more than one energy transmission coil 125, whereby the basic principle of data transmission remains identical. The control electronics units 123 have a communication interface 147 and a coil control unit 149. The stationary units 111 can further have control elements integrated into the coil control unit 149 or additionally provided for controlling the drive coils 135. The coil control unit 149 therefore refers, if necessary, exclusively to the control of the energy transmission coils 125. In Fig. 3 Three stationary units 111 are shown. A total of a first energy transmission coil 151 with first control electronics 161, a second energy transmission coil 153 with second control electronics 163, and a third energy transmission coil 155 with third control electronics 165 are provided. Data signals from the control unit 133 can be forwarded to the coil controllers 149 via the communication interfaces 147. Data communication between the control unit 133 and the communication interfaces 147 can take place, for example, using the EtherCAT protocol. The control electronics 123 can also be configured to control other elements of the stationary units 111, such as drive coils 135 or the position detection element 143.

[0039] Fig. 4 shows a data curve of such a data communication plotted over time 170. A header frame 173, a first data frame 175 for the first control electronics 161, a second data frame 177 for the second control electronics 163, and a third data frame 179 for the third control electronics 165 are output. Furthermore, an interrupt signal 171 can be output, by means of which all control electronics 123 can be synchronized. The interrupt signal 171 can be used, for example, to operate a PLL of the first control electronics 161, the second control electronics 163, and the third control electronics 165.

[0040] To control the energy transmission coils 125, the control electronics 123 can perform the following steps. First, an energy quantity signal for the respective energy transmission coil 125 can be read in. This energy quantity signal can be provided, for example, by the control unit 133. The energy quantity signal is then converted by the control electronics 123 into a pulse-to-pause ratio, and the energy transmission coil 125 is controlled based on the pulse-to-pause ratio. The pulse-to-pause ratio can be determined, for example, by a clock or by evaluating a predetermined oscillation, for example, in an oscillating circuit.

[0041] In one embodiment, a counter is started in the control electronics 123, in particular in the coil control 149, and the conversion of the energy quantity signal into the pulse-pause ratio is carried out by means of the counter.

[0042] Fig. 5 shows schematically how the energy transmission coils 125 can be electronically controlled. A data signal originating from the control unit 133 is processed by the control electronics 123. In particular, the data signal is received by the communication interface 147 and forwarded to the coil control 149. The coil control 149 comprises a driver 150 as well as a first half-bridge 190 and a second half-bridge 191. The first half-bridge 190 comprises a first half-bridge center point 192, and the second half-bridge 191 comprises a second half-bridge center point 193. The energy transmission coil 125 is arranged between the first half-bridge center point 192 and the second half-bridge center point 193. The first half-bridge 190 further comprises a first switch 194 and a second switch 195, with the first half-bridge center point 192 being arranged between the first switch 194 and the second switch 195.The second half-bridge 191 comprises a third switch 196 and a fourth switch 197, wherein the second half-bridge center point 193 is arranged between the third switch 196 and the fourth switch 197. Furthermore, as shown in . Fig. 5 As shown, the first switch 194 and the third switch 196 are connected to a potential 198, while the second switch 195 and the fourth switch 197 are connected to a common ground point 199. Depending on the position of the first to fourth switches 194, 195, 196, 197, a current can flow through the energy transmitting coil 125. In particular, the coil control 149 simultaneously switches the first switch 194 and the fourth switch 197 or the second switch 195 and the third switch 196 to conduct, thus conducting a current forward or backward through the energy transmitting coil 125.

[0043] Fig. 6 shows process sequences for a counter 201, a first switching signal waveform 203 of the first switch 194 and the fourth switch 197, a second switching signal waveform 205 of the second switch 195 and the third switch 196, an applied coil voltage 207 resulting from the first switching signal waveform 203 and the second switching signal waveform 205, and a coil current 209, each plotted against time 170. The coil current 209 is shown ideally and without further losses. The counter 201 counts upwards from a minimum value 210 to a maximum value 211 and then downwards from the maximum value 211 back to the minimum value 210. The energy quantity signal transmitted by the control unit 133 is linked to an upper counter value 212 and a lower counter value 213.If the counter 201 is above the upper counter value 212, the first switch 194 and the fourth switch 197 are switched on, as can be seen from the first switching signal curve 203. If the counter 201 is below the lower counter value 213, the second switch 195 and the third switch 196 are switched on, as can be seen from the second switching signal curve 205. Since the voltage applied to the energy transmission coil 125 is reversed due to the control by the first half-bridge 190 and the second half-bridge 191, the curve of the applied coil voltage 207 results. The ideal coil current 209 results from this applied coil voltage 207. Fig. 6 shows the maximum possible control with applied coil voltage 207 at 50 percent of the time.

[0044] Fig. 7 shows a curve of the counter 201, the first switching signal curve 203, the second switching signal curve 205, the coil voltage 207 and the coil current 209 for the case that the upper counter value 212 is increased and the lower counter value 213 is decreased. In this case, a power is transmitted by means of the energy transmitting coil 125 which is smaller than the power of the Fig. 6 shown energy transfer, which is caused in particular by the shortened switching pulses of the applied coil voltage 207 and leads to a smaller effective coil current 209.

[0045] In one embodiment, a nominal power is to be transmitted. Then, the upper counter value 212 can be greater than three-quarters of the difference between the maximum value 211 and the minimum value 210, plus the minimum value 210. The lower counter value 213 can be less than one-quarter of the difference between the maximum value 211 and the minimum value 210, plus the minimum value 210. In particular, it can be provided that the upper counter value 212 is at least seven-eighths of the difference between the maximum value 211 and the minimum value 210, plus the minimum value 210, and the lower counter value 213 is at most one-eighth of the difference between the maximum value 211 and the minimum value 210, plus the minimum value 210.

[0046] In order to transmit a peak power exceeding the rated power, the upper counter value 212 is at least three-quarters of the difference between the maximum value 211 and the minimum value 210 plus the minimum value 210 and the lower counter value 213 is at most one-quarter of the difference between the maximum value 211 and the minimum value 210 plus the minimum value 210. This is the Fig. 6 illustrated case, in which, in the course of the applied coil voltage 207, there are identical time intervals without voltage between the voltage pulses. In this case, a large effective value of the coil current 209 results and thus the greatest possible energy transfer. In particular, it can be provided that for the transmission of the rated power, the upper counter value 212 is at least seven-eighths of the difference between the maximum value 211 and the minimum value 210 plus the minimum value 210 and the lower counter value 213 is a maximum of one-eighth of the difference between the maximum value 211 and the minimum value 210 plus the minimum value 210 and for the transmission of the peak power, the upper counter value 212 is exactly three-quarters of the difference between the maximum value 211 and the minimum value 210 plus the minimum value 210 and the lower counter value 213 is exactly one-quarter of the difference between the maximum value 211 and the minimum value 210 plus the minimum value 210.If a power exceeding the rated power is to be transmitted which is less than the peak power, the upper counter value 212 is greater than three quarters of the difference between the maximum value 211 and the minimum value 210 plus the minimum value 210 and less than seven eighths of the difference between the maximum value 211 and the minimum value 210 plus the minimum value 210 and the lower counter value 213 is less than one quarter of the difference between the maximum value 211 and the minimum value 210 plus the minimum value 210 and greater than one eighth of the difference between the maximum value 211 and the minimum value 210 plus the minimum value 210.

[0047] To simplify the underlying equations, it can be provided that the minimum value 210 is defined as zero and the counter counts from zero to the maximum value 211.

[0048] The peak power exceeding the rated power can be used, in particular, to transmit a higher power required for a short period of time, whereby the rated power corresponds to the maximum power that can be transmitted during continuous operation. For example, the rated power can be a maximum of 250 watts, and the peak power 500 watts. In particular, the rated power can be a maximum of 125 watts, and the peak power 250 watts. Furthermore, the rated power can be between 10 and 50 watts, in particular 30 watts. The peak power can then be between 50 and 90 watts, in particular 70 watts.

[0049] Fig. 8 shows a temperature 215 plotted over time 170 for various switching states. The temperature 215 can, in particular, be a surface temperature of the stationary unit 111 or the housing of the stationary unit 111, or the temperature of the component of the stationary unit 111 that is most temperature-sensitive. A first temperature profile 221 corresponds to a transmission of the rated power when the energy transmission is switched on.

[0050] This is followed by an exponential rise in temperature, asymptotically approaching a maximum value corresponding to a maximum temperature at which the energy transfer can still operate safely. The maximum temperature can result from standards according to which electrical devices must not exceed a certain temperature on a touchable surface, such as 105 degrees Celsius, or from specified operating temperatures of components of the stationary units 111. A second temperature curve 223 represents an increased temperature at which peak power is initially transmitted and then reduced to the rated load when the maximum temperature is reached. A third temperature curve 225 corresponds to the termination of the energy transfer when the energy transmission coil 125 is de-energized again after the maximum temperature value was previously reached.

[0051] Fig. 9 shows a schematic view of a stationary unit 111, wherein the stationary unit 111 in this embodiment comprises a first energy transmitting coil 151 and a second energy transmitting coil 153. The stationary unit 111 further comprises first control electronics 161 for controlling the first energy transmitting coil 151 and second control electronics 163 for controlling the second energy transmitting coil 153. The first control electronics 161 and the second control electronics 163 can correspond to the control electronics 123 described above. A movable unit 103 with an energy receiving coil 127 is also shown.If the position data of the energy receiving coil 127, which can correspond to the position data of the movable unit 103, show that the energy receiving coil 127 moves from the first energy transmitting coil 151 to the second energy transmitting coil 153 and the first control electronics 161 and the second control electronics 163 are synchronized using the interrupt signal 171, this is implemented in the first control electronics 161 and the second control electronics 163 by the respective counters 201 being started simultaneously for the first control electronics 161 and the second control electronics 163 (in the . Figuren 6 and 7(shown for a counter 201, respectively). The energy quantity signal is output to both the first control electronics 161 and the second control electronics 163 and linked to the upper counter value 212 and the lower counter value 213, whereby this link is identical for the first control electronics 161 and the second control electronics 163. The first switching curve 203 and the second switching curve 205 are then identical for both the first energy transmission coil 151 and the second energy transmission coil 153 and can be analogous to the Figuren 6 and 7The first energy transmitting coil 151 and the second energy transmitting coil 153 are then supplied with a synchronous current. If the movable unit 103 is now moved from the first energy transmitting coil 151 to the second energy transmitting coil 153, the synchronous current supply to the first energy transmitting coil 151 and the second energy transmitting coil 153 results in the least possible interference due to the movable unit 103 moving from the first energy transmitting coil 151 to the second energy transmitting coil 153. The magnetic fields of the first energy transmitting coil 151 and the second energy transmitting coil 153 then overlap in a temporally ideal manner. As a result, the energy receiving coil 127 receives a sum of the two fields.If the two magnetic fields of the first energy transmitting coil 151 and the second energy transmitting coil 153 are not synchronous, but for example are shifted in time, they could interfere with each other or the sum of the two fields would be smaller, for example if one field were still positive and the other already negative.

[0052] Furthermore, in this exemplary embodiment, as already described, it can be provided to decrease the upper counter value 212 and increase the lower counter value 213 when the energy receiving coil 127 is arranged between the first energy transmitting coil 151 and the second energy transmitting coil 153, since in a space between the first energy transmitting coil 151 and the second energy transmitting coil 153, a reduced magnetic flux hits the energy receiving coil 127, and this reduced flux can be compensated by the increased current supply to the first energy transmitting coil 151 and the second energy transmitting coil 153. It can be provided that a first length 181 of the energy transmitting coils 125 is greater than a second length 183 of a transition region, and the second length 183 is greater than a third length 185 of the energy receiving coil 127.The first length 181, the second length 183 and the third length 185 refer to a direction of travel 187 along the guide rail 105.

[0053] Furthermore, it can be provided that a thermal load on the energy transfer is determined and a cooling time is calculated. A further reduction of the upper counter value 212 and a further increase of the lower counter value 213 then only occurs after the cooling time. In this way, it can be achieved that an overall thermal load on the energy transfer can be controlled and kept lower than a maximum thermal load. It can also be provided that the current supply to the drive coils 135 can be changed such that the movable unit 103 moves faster while the movable unit 103 moves from the first energy transmission coil 151 to the second energy transmission coil 153, in order to reduce the drive current when the movable unit 103 is in the area of ​​the first energy transmission coil 151 or the second energy transmission coil 153.As a result, the average speed of the movable unit 103 can be kept constant, and the movable unit 103 can be moved faster in the transition region between the first energy transmission coil 151 and the second energy transmission coil 153 to further reduce the thermal load on the system. In particular, an increase period during which the current through the drive coils 135 is increased can be calculated from the speed of the movable unit 103.

[0054] It may further be provided to adjust the upper counter value 212 and the lower counter value 213 based on a temperature measured in the area of ​​the energy transmission coils 125. This adjustment can, in particular, reduce the thermal load on the energy transmission, at the expense of an increased thermal load on the drive coils 135. In many operating cases, however, a larger thermal reserve is available for the drive coils 135.

[0055] Fig. 10 shows an electrical circuit of the movable unit 103. The current transmitted by the energy receiving coil 127 can be rectified by a rectifier 231 and subsequently smoothed by a capacitor 233. Furthermore, a charging controller 235 for a rechargeable battery 237 is provided, wherein the charging controller 235 controls the charging and discharging of the rechargeable battery 237. Furthermore, a load 239, for example, an electric motor or another tool, can serve as a power consumer. A capacitor 233 can also be arranged in the region of the load 239. In particular, only one of the two capacitors 233 can be provided, and the capacitor 233 can be connected in parallel with the energy receiving coil 127.

[0056] Fig. 11shows a synchronization signal 241, a data transmission signal 243, as well as the first switching signal waveform 203 and the second switching signal waveform 205. The synchronization signal 241 can include an interrupt signal 171, from which the counters 201 of the control electronics 123 are each started. The data transmission signal 243 can include a data transmission edge 245, wherein, at the data transmission edge 245, for example, a data transmission can be triggered by means of the stationary antenna 129 and the movable antenna 131. In the event that the data transmission is critical, it can be provided that omitted switching pulses 247 are provided in the first switching signal waveform 203 and the second switching signal waveform 205, which occur directly after the data transmission edge 245.This is represented by dotted lines in the first switching signal waveform 203 and the second switching signal waveform 205, whereby the switching pulse 247 represented by a dotted line can be omitted in each case. This means that although the energy transmission coil 125 should be supplied with voltage after the counter 201 or the upper counter value 212 and the lower counter value 213, no energy is transferred due to the data transmission in order to ensure data transmission. Critical data transmissions can include, in particular, safety-critical data transmissions.

[0057] It may further be provided to determine position data of the energy receiving coils 127 of the movable unit 103, for example, using the position detection element 143 and the position sensor 145. Subsequently, the energy transmitting coil 125 within the linear transport system 101 that is closest to the energy receiving coil 127 is selected. Thus, the energy transmitting coil 125 is selected based on the position data. The energy quantity signal is then output to the control electronics 123 of the selected energy transmitting coil 125. List of reference symbols

[0058] 101Transport system 103Moving unit 105Guide rail 107Linear motor 109Stator 111Stationary unit 113Rotor 117Magnet 123Control electronics 125Energy transmitting coil 126First coil section 127Energy receiving coil 128Second coil section 129Stationary antenna 131Movable antenna 133Control unit 135Drive coil 137Tool 139Roller 141Running surface 143Position detection element 145Position sensor 147Communication interface 149Coil control 150Driver 151First energy transmitting coil 153Second energy transmitting coil 155Third energy transmitting coil 161First control electronics 163Second control electronics 165Third Control electronics 170 Time 171 Interrupt signal 173 Header frame 175 First data frame 177 Second data frame 179 Third data frame 181 First length 183 Second length 185 Third length 187 Direction of travel 190 First half-bridge 191 Second half-bridge 192 First half-bridge center point 193 Second half-bridge center point 194 First switch 195 Second switch 196 Third switch197 fourth switch 198 potential 199 common ground point 201 counter 203 first switching signal curve 205 second switching signal curve 207 coil voltage 209 coil current 210 minimum value 211 maximum value 212 upper counter value 213 lower counter value 215 temperature curve 221 first temperature curve 223 second temperature curve 225 third temperature curve 231 rectifier 233 capacitor 235 charge control 237 accumulator 239 load 241 synchronization signal 243 data transmission signal 245 data transmission edge 247 switching pulse

Claims

1. A method for transferring energy from a stationary unit (111) to a movable unit (103) of a linear transport system (101), the linear transport system (101) comprising a guide rail (105) for guiding the movable unit (103), a plurality of stationary units (111), a controller (133) as well as a linear motor (107) for driving the movable unit (103) along the guide rail (105), the linear motor (107) comprising a stator (109) and a rotor (113), the stator (109) including the stationary units (111) each comprising one or a plurality of drive coils (135), the rotor (113) being arranged on the movable unit (103) and comprising one or a plurality of magnets (117), the stationary units (111) each comprising one or a plurality of energy-transmitting coils (125), each energy-transmitting coil (125) having an actuation electronics (123), characterized in that the movable unit (103) comprises at least one energy-receiving coil (127), wherein the controller (133) carries out the following steps: - detecting position data of the energy-receiving coil (127) of the movable unit (103), - selecting energy-transmitting coils (125) of the stationary units (111) on the basis of the position data of the energy-receiving coil (127) of the movable unit (103), and - outputting an energy quantity signal to the actuation electronics (123) of the selected energy-transmitting coils (125), wherein the actuation electronics (123) of the selected energy-transmitting coils (125) carry out the following steps: - reading in the energy quantity signal for the relevant energy-transmitting coil (125); - converting the energy quantity signal into a pulse-pause ratio for actuating the energy-transmitting coil (125) with the aid of a counter (201), and - actuating the energy-transmitting coil (125) based on the pulse-pause ratio in order to control a current through the energy-transmitting coil (125), wherein, if the position data of the energy-receiving coil (127) of the movable unit (103) determined by the controller (133) reveal that the energy-receiving coil (127) of the movable unit (103) moves away from a first energy-transmitting coil (151) to a second energy-transmitting coil (153), wherein the energy quantity signal is output to a first actuation electronics (161) of the first energy-transmitting coil (151) and to a second actuation electronics (163) of the second energy-transmitting coil (153) and the first actuation electronics (161) of the first energy-transmitting coil (151) and the second actuation electronics (163) of the second energy-transmitting coil (153) are each synchronized on the basis of a synchronization signal (241) of the controller (133), wherein a first counter of the first actuation electronics (151) and a second counter of the second actuation electronics (161) are started simultaneously on the basis of a synchronization signal (241).

2. The method according to claim 1, wherein the actuation electronics (123) comprises at least a first half-bridge (190) having a first switch (194) and a second switch (195) and a second half-bridge (191) having a third switch (196) and a fourth switch (197), wherein the energy-transmitting coil (125) is arranged between a first half-bridge center (192) and a second half-bridge center (193), the first half-bridge center (192) being arranged between the first switch (194) and the second switch (195), the second half-bridge center (193) being arranged between the third switch (196) and the fourth switch (197), wherein the counter (201) respectively counts up from a minimum value (210) to a maximum value (211) and then counts down from the maximum value (211) to the minimum value (210), the energy quantity signal being associated with an upper counter value (212) and a lower counter value (213), wherein the first switch (194) and the fourth switch (197) are rendered conductive when the counter (201) is above the upper counter value (212), and the second switch (195) and the third switch (196) are rendered conductive when the counter (201) is below the lower counter value (213).

3. The method according to claim 2, wherein the upper counter value (212) is larger than three-fourths of a difference of the maximum value (211) and the minimum value (210) plus the minimum value (210) and the lower counter value (213) is less than one-fourth of the difference of the maximum value (211) and the minimum value (210) plus the minimum value (210) when a nominal power is to be transmitted.

4. The method according to claim 3, wherein for transmitting the nominal power, the upper counter value (212) is at least seven-eighths of the difference between the maximum value (211) and the minimum value (210) plus the minimum value (210), and the lower counter value (213) is at most one-eighth of the difference between the maximum value (211) and the minimum value (210) plus the minimum value (210).

5. The method according to claim 3 or 4, wherein for transmitting a peak power exceeding the nominal power, the upper counter value (212) is at least three quarters of the difference between the maximum value (211) and the minimum value (210) plus the minimum value (210), and the lower counter value (213) is at most one quarter of the difference between the maximum value (211) and the minimum value (210) plus the minimum value (210).

6. The method according to any one of claims 2 to 5, further comprising reading in a data transmission signal (243) from the actuation electronics (123), wherein the data transmission signal (243) includes that a data transmission is taking place in the region of the energy-transmitting coil (125), wherein at least once, when the counter (201) is above the upper counter value (212), the first switch (194) and the fourth switch (197) are switched to non-conductive, and at least once when the counter (201) is below the lower counter value (213), the second switch (195) and the third switch (196) are switched to non-conductive.

7. The method according to any one of claims 2 to 6, wherein, when the position data indicates that the energy-receiving coil (127) is located between the first energy-transmitting coil (151) and the second energy-transmitting coil (152), the upper counter value (212) is reduced and the lower counter value (213) is increased.

8. The method according to claim 7, wherein in the event that a power larger than the nominal power is to be transmitted, a thermal load of the energy transmission is determined and a cooling-off time is calculated, wherein a renewed reduction of the upper counter value (212) and a renewed increase of the lower counter value (213) such that a power larger than the nominal power may be transmitted occurs only after the cooling-off time.

9. The method according to claim 7 or 8, wherein a current to the drive coils (135) is changed in such a way that the movable unit (103) moves faster.

10. The method according to claim 9, wherein an increase time period during which the energizing of the drive coils (135) is changed is calculated from a speed of the movable unit (103).

11. The method according to any one of claims 2 to 10, wherein the upper counter value (212) and the lower counter value (213) are adjusted based on a temperature measured in the region of the energy-transmitting coil (125).

12. A linear transport system (101) comprising at least one stationary unit (111) and at least one movable unit (103), and a controller (133), wherein the linear transport system (101) comprises a guide rail (105) for guiding the movable unit (103), a plurality of stationary units (111), and a linear motor (107) for driving the movable unit (103) along the guide rail (105), the linear motor (107) comprising a stator (109) and a rotor (113), the stator (109) comprising the stationary units (111), each comprising one or a plurality of drive coils (135), the rotor (113) being arranged on the movable unit (103) and comprising one or a plurality of magnets (117), the stationary units (111) each comprising one or a plurality of energy-transmitting coils (125), each energy-transmitting coil (125) comprising an actuation electronics (123), characterized in that the movable unit (103) comprises at least one energy-receiving coil (127), wherein the controller (133) is set up to determine position data of the energy-receiving coil (127) of the movable unit (103), to select energy-transmitting coils (125) of the stationary units (111) on the basis of the position data of the energy-receiving coil (127) of the movable unit (103), and to output an energy quantity signal to the actuation electronics (123) of the selected energy-transmitting coils (125), the actuation electronics (123) being set up to read in an energy quantity signal for the relevant energy-transmitting coil (125), to convert the energy quantity signal it into a pulse-pause ratio and to actuate the energy-transmitting coil (125) on the basis of the pulse-pause ratio in order to control a current through the energy-transmitting coil (125), wherein, if the position data of the energy-receiving coil (127) of the movable unit (103) determined by the controller (133) reveal that the energy-receiving coil (127) of the movable unit (103) moves away from a first energy-transmitting coil (151) to a second energy-transmitting coil (153), wherein the energy quantity signal is output to a first actuation electronics (161) of the first energy-transmitting coil (151) and to a second actuation electronics (163) of the second energy-transmitting coil (153) and the first actuation electronics (161) of the first energy-transmitting coil (151) and the second actuation electronics (163) of the second energy-transmitting coil (153) are each synchronized on the basis of a synchronization signal (241) of the controller (133), wherein a first counter of the first actuation electronics (151) and a second counter of the second actuation electronics (161) are started simultaneously on the basis of a synchronization signal (241).

13. The linear transport system (101) according to claim 12, wherein the actuation electronics (123) comprises at least a first half bridge (190) having a first switch (194) and a second half bridge (191) having a third switch (196) and a fourth switch (197), wherein the energy-transmitting coil (125) is arranged between a first half-bridge center (192) and a second half-bridge center (193), wherein the first half-bridge center (192) is arranged between the first switch (194) and the second switch (195), wherein the second half-bridge center (193) is arranged between the third switch (196) and the fourth switch (197), wherein the counter (201) in each case counts up from a minimal value (210) to a maximum value (211) and subsequently counts down from a maximum value (211) to a minimal value (210), wherein the energy quantity signal is linked to an upper counter value (212) and to a lower counter value (213), wherein the first switch (194) and the fourth switch (197) are switched to conductive if the counter (201) is above the upper counter value (212) and the second switch (195) and the third switch (196) are switched to conductive if the counter (201) is below the lower counter value (213).

14. The linear transport system (101) according to claim 13, wherein, if the position data reveal that the energy-receiving coil (127) is arranged between the first energy-transmitting coil (151) and the second energy-transmitting coil (152), the upper counter value (212) is reduced and the lower counter value (213) is increased.

15. The linear transport system (101) according to claims 13 or 14, wherein the upper counter value (212) and the lower counter value (213) are adjusted on the basis of a temperature measured in the region of the energy-transmitting coil (125).