HK1024991B - Method and device for inductive transmission of electric power to a plurality of mobile consumers - Google Patents

Description

The invention relates to a process and device for inductive transmission of electrical power to several moving consumers as described in the general concept of claim 1, as is known from the generic reference WO-A1-96/20526.

In WO-A1-96/20526 (compliant with DE 44 46 779) a method for inductive transmission of electrical power from a medium frequency power source with a frequency fM to one or more moving consumers is described via a longitudinal transmission line and inductive collectors IAx, IAY assigned to the moving consumers with downstream rectifier members to adjust the power received from the transmission line and buffers connected to the moving consumers, which reveal the power supplied PLX, PLY, whereby the transmission line of a power source with a power transmission is fed at its effective constant frequency (IL) during the power transmission.

A method and arrangement for the inductive transmission of electrical power to several moving consumers is known from the application WO 92 /17929 A1 and the publication by A. W. Green and T. Boys, Power Electronics and Variable-Speed Drives, 26-28 October 1994, Conference Publication No 399, C IEE, 1994, pages 694 to 698, which describes the invention in accordance with WO 92 /17929 A1.

As shown in Figures 3 to 3 of this publication, the current taken from a rotating current network is aligned and fed via a power supply component consisting of IGBTs S1, S2, diodes D1, D2 and a storage lathe Ld to an inverter consisting of IGBTs S3 and S4 and the magnetically coupled inductances L2a and L2b, which generates a mean frequency alternating current of 10 kHz and feeds it into a parallel transmission circuit of inductivity L1 and capacity C1. The inductivity L1 is the double-current inductive transmission line of a transmission line, again stretched, to transmit electrical power to a consumer. The inductive transmission lines are moved through a magnetic transmission system, as shown in Figure 1. The inductive transmission line is a two-way inductive transmission line, with a conductive inductive transmission line, which is used to transmit power to a consumer.

The current transmitted from the transmission line to the parallel oscillating circuit of the moving receiver is aligned in a rectifier called a receiver controller, as shown in Fig. 10, smoothed with a throttle and, depending on the power demand of the consumer connected to the controller, either fed to the capacitor buffering the output voltage V0 of the controller or passed through this buffer capacitor. The decision to do so is taken by the controller's intermediate, who compares the output voltage V0 with a corresponding upstream voltage and blocks the IGBT if the output voltage is too small so that the current flows through the output capacitor or the IGBT into the current conductor, so that the current flows through the output voltage V0 after passing a reference voltage.

This method of power transmission, as described in column 1, page 697 and illustrated in Fig. 7 of the publication, causes undesirable oscillations in the entire transmission system in the event of sudden changes in load, which involves the mutual influence of the energy transmission of several vehicles and requires additional attenuation measures.

These adverse events are caused by: The switch on the receiver controller, which does not allow a stepless change in the power received by the inductive receiver and the voltage coupled to the transmission line, activates a strong stimulation of the parallel oscillating circuit formed by the transmission line and the capacitor C1 in Fig. 3.The energy received from the transmission line is first withdrawn from the parallel oscillating circuit and only delayed via the input current converter due to the inductivities contained in it and returned after a voltage change at the capacitor C1 has been detected.

The purpose of the invention is to describe a method for inductive transmission of electrical power to several moving consumers, which does not involve induction operations in the current of the transmission line shared by all moving consumers.

The problem is solved by the characteristics of the independent claims, and further and more advantageous arrangements are given in the subclaims and description.

The essence of the invention is to be found in the creation of a process and an arrangement for inducing the transmission of electrical power from a stationary transmission line to moving consumers, whereby the transmission line from a medium frequency power source whose output voltage UL is gradually adjusted to the value corresponding to the consumer power variable TS in a short half-life of the medium frequency setting time, is fed with a constant medium frequency current IL and the rate of change of the power received by the transmission line via the inductive receivers of the moving systems by actuators whose setting time is greater than the setting time TS of the medium frequency power source TA is limited in such a way that the medium frequency current can easily follow the source with the corresponding power output.

The invention has the advantage of reliably avoiding the use of induction, and of simultaneously preventing the interaction of moving consumers.

The method of the invention has the following additional advantages over the state of the art: The transmission frequency is power independent and constant, the inductive transceivers are always operated at their resonance point, i.e. at their operating point of optimal utilization.

The following features, in so far as they are essential to the invention, are explained in detail and described in more detail by means of figures. Fig. 1: a block diagram of the entire system for the inductive transmission of electrical power to several moving consumers,Fig. 2a: the time course of the current embedded in the transmission line IL,Fig. 2b: the time course of the voltage coupled to the transmission line by an inductive receiver of a moving system UH,Fig. 2c: the time course of the consumption power Pv and the average value of the power taken from the transmission line PL,Fig. 3: the circuit principle of the design-appropriate arrangement,Fig. 4a: the time course of the pulse-gram output voltage uW of the NF/MF converter and the corresponding spigot-switch.Fig. 5a: a model for the formation of a pulse-gram output voltage for a small consumer.Fig. 4a: a model for the formation of a UF-switch.Fig. 7a: a model for the formation of a pulse-gram output voltage in the case of a large power supply,Fig. 5a: a model for the formation of a UF-switch.

The method of the invention is first explained in general terms by means of the block diagram shown in Figure 1 and the diagrams in Figures 2a to 2c.

The block diagram shows a transmission line, for example, formed as a double conductor, connected via a series-connected capacitor CL to a rapidly and continuously adjusting medium-frequency power source. The invention is independent of the formation of the transmission line and therefore also applicable to the coaxial conductor arrangement according to DE 44 46 779 C2. The fast-set medium-frequency power stream, realized from a low-frequency-medium-frequency circuit with a back-connection network, described in more detail below, is characterized by a transmission source that is sinusoidal in its effective value and has a constant frequency current with the frequency of the fM in a transmission line. A frequency of around 20 kHz is preferred.

The inductive receivers IAX and IAY are magnetically and inductively coupled to the transmission line by two moving systems X and Y, for example. This coupling is done by the main magnetic currents ΦHX and ΦHY shown in Fig. 1, which together impose the conductive loop of the transmission line and the winding of the inductive receivers. These magnetic currents have the same frequency as the current IL of the transmission line and induce corresponding voltages in it. In addition, the current IL generates over the entire length of the transmission line in addition to the conductor ΦL, which induces a high inductive voltage transfer current drop on the overhead line.

In particular, the capacitor CL in series with the transmission line is measured so that the inductive voltage drop on the transmission line is fully compensated by the voltage at the capacitor CL. If the ohmic voltage drop on the line is neglected, the voltage UL at the output of the power source is equal to the sum of the voltages induced by the main magnetic currents ΦHX and ΦHY in the conductive loop.

A fast and continuous adjusting power source according to the invention means that the power source can adjust to power changes, i.e. to the required UL output voltage, at least as quickly or more rapidly and continuously than when these are coupled to the transmission line via the inductive receptors.

Under this condition, the advantage is that the UL voltage at the output of the medium frequency power source is at all times equal to the sum of the voltages induced by the inductive receptors in the transmission line, even under dynamic power changes, i.e. the voltages at the line inductivity and the in-line capacity CL do not change and no oscillation occurs.

Since the setting time TS of the medium frequency power source cannot be arbitrarily small, the power taken up by the transmission line via the inductive receivers is set in stepless fashion and with a limited rate of change according to the invention on moving systems, so that the set time TA of the transmitted power is greater than the setting time TS of the medium frequency power source.

The medium frequency power source has a maximum set time (TS) of its output signal which is less than the set time (TA) of the power consumption at the consumer.

For this purpose, as shown in Figure 1, it is preferable to connect on the moving systems between an energy buffer from which the connected consumers can draw power at any rate of increase and the inductive receiver IA a current rectifier, controlled by a signal SB in such a way that the power is taken from the transmission line continuously and with a limited rate of change.

The capacitor CK, connected parallel to the inductive receiver IA at the input of the rectifier, forms a parallel oscillating circuit with the inductivity of the receiver, which resonates at the frequency fM of the transmission line current IL. At this resonance, the capacitor CK supplies the entire magnetization current of the inductive receiver, and the transmission line is loaded, as shown by the phase equality of the transmission line current IL shown in Fig. 2a and the inductive receiver IA shown in Fig. 2b, with the voltages UH1 and UH2 coupled to the transmission line PL, with pure power output. In Fig. 2c, two very different, opposite power supply voltages are simultaneously produced, which are the power consumed by PV1 and PV2 during the transmission line and the power output of the TV2 and the voltages applied to the transmission line by the PL1 and the voltages applied to the TV2 are also constantly changing and changing.

In operating times when all moving consumers have a simultaneous lower power demand, especially during common downtimes of the drives producing the motion, or during the start-up and shutdown of the whole system, the introduction of smaller flows of IL into the transmission line is advantageous. The low frequency/medium frequency converter (NF/MF converter) therefore has an E-ILSOLL signal, as shown in Figure 1, which allows the provision of any IL flows between the zero input value and a maximum power value. The requirements for the rate of change of this signal are low. It is essentially measurable as the rate of change of the transmission line is less than the power input value.

For many applications, an unregulated adjustment of the transmission line current is sufficiently accurate; however, when exposed to strong interference, higher precision of the transmission line current can be achieved advantageously if it is measured and the measurement quantity ILM, as shown in Figure 1, is fed to the NF/MF converter at the tick of the transmission line current adjustment to the set ILSOL ILL.

The principle of operation of a particularly advantageous arrangement for the realization of the process of the invention is shown in Fig. 3. The left part of the switch is the fast-adjusting medium frequency power source consisting of the NF/MF converter and the coupling network.

The NF/MF converter consists of a DC-bridge rectifier G1 with a down-linked single-phase pulse converter W. The two current converters are connected via a DC-interval circuit to the DC-UG and the buffer capacitor CG. The IGBTS T1 to T4 of the inverter are switched on and off via the signals S1 to S4 generated in a pulse duration modulation step PM1 in such a way that at the connection network connected to the inverter the pulsed alternating voltage uW as shown in Fig. 4 is generated. The maximum frequency fM of this alternating voltage is constant and the frequency of modulation is transmitted by a modulation generator. The frequency of modulation is also variable in its value from P to N. The value of the frequency of modulation is also variable in its value from N to T. The maximum value of the frequency of modulation is also variable in its value from N to T. The value of the frequency of modulation is also variable in its value from N to T. The value of the frequency of modulation is also variable in its value from N to T. The value of the frequency of modulation is also variable in its value from N to T. The value of the frequency of the modulation is also variable in its value from N to T. The value of the modulation is also variable in its value is variable in its value from N to T. The value of the frequency of the modulation is also variable in the frequency of the modulation is equal to T.

The coupling network consists essentially of a series oscillating circuit with inductance L1 and capacity C1, the transmission line being coupled to capacity C1. The network acts as a filter which suppresses the over-vibrations contained in the pulsed AC voltage and transmits the base vibration to the transmission line. The further considerations of the coupling network according to the invention are therefore limited to its basic oscillatory behaviour.

Using complex quantities, the output voltage U2 of the spare circuit is calculated as: $U_2=\frac{U_1}{{\mathrm{j\omega L}}_1}\cdot \frac{1}{j\sqrt{\frac{C_1}{L_1}}\left(\frac{\omega }{{\omega }_1},-,\frac{{\omega }_1}{\omega }\right)+\frac{1}{Z}},$

In this case ω = 2πfM and ${\omega }_1=\frac{1}{\sqrt{\left(L_1,,C_1\right)}}\mathrm{.}$

In the design of the series oscillator circuit according to the invention for the resonance case ω1 = ω, the output voltage U2 to be drawn from the capacitor C1 and the output current I2 to any impedance Z are calculated as: $U_2=-j\frac{U_1}{\sqrt{\frac{L_1}{C_1}}}\cdot Z,I_2=-j\frac{U_1}{\sqrt{\frac{L_1}{C_1}}}$

These relationships show that the NF/MF converter shown in Fig. 3 and the connected series oscillator circuit form a medium frequency current source at resonance, which drives a current I2 into any impedance Z and thus into the transmission line connected to the capacity C1 in Fig. 3 via the transformer TR, depending only on the base voltage U1 and the dimensioning of the series oscillator circuit.

The voltage U2 at capacity C1, i.e. at the output of the medium frequency power source, is equal to the product of the current I2 and the connected impedance Z. The power P1 transmitted from the coupling network is generally: $P_1=\frac{{U_1}^2}{\sqrt{\frac{L_1}{C_1}}}\cdot \frac{R}{\sqrt{\frac{L_1}{C_1}}}$

Here R is an ohmic resistance thought in the current path of I2.

The equation for the output current of the current source I2 shows that this can be adjusted via the voltage base vibration U1 and thus via the pulse duration TD by the signal SD fed to the pulse duration modulation stage PM1.

In addition, component tolerances, which also depend on temperature, for example, can cause further deviations of the transmission current IL from the target value. It is therefore advantageous, with higher requirements for the accuracy of the power to be transmitted, as shown in Fig. 3, to measure the transmission current and the deviation of the measurement size ILM from the target value ILSOLL with a controller that produces an SDR signal as another component of the signal controlling the pulse duration of the TD signal. This controller only affects the transmission current to achieve a higher power and not to affect the transmission current to achieve a higher power.

The hand diagrams in Figures 5b and 5c illustrate two special cases of the load on the power source of the invention. $\sqrt{\left(L_1,/,C_1\right)}$ In this case, the output current I2 and the capacitor current IC1 are of equal size, and the inverter output current I1 is accelerated relative to the voltage base vibration U1 around the phase angle φ1=45°. It has been shown that in this case of load the blind power of the inductance L1 relative to the power P1 and thus their dimensions are minimal. $R=\sqrt{\left(L_1,/,C_1\right)}$ In the case of a vacuum run, R = 0. In the case of a short circuit, Z = 0. This corresponds to a short circuit capacitor C1 and the pointer diagram in Fig. 5c.

The coupling network of the invention has a load range of 1 in the operationally preferred load range. $0<R\le \sqrt{\left(L_1,/,C_1\right)}$ The device has excellent damping properties and, in the event of sudden changes in the load resistance R, oscillates to the new stationary state in a few half-periods of the medium frequency fM without overvoltage.

By choosing the transition ratio w1/w2 of the transformer TR in Fig. 3, the effective replacement resistors RXN' on the transmission line at the nominal power input of the moving systems are adjusted so that their sum at capacitor C1 satisfies the condition $\sum R_{\mathrm{XN}}ʹ=\sqrt{\left(L_1,/,C_1\right)}$ The Commission has

Fig. 6a shows a replacement circuit diagram of the arrangement of the invention with transmission line and three moving systems. The part of the arrangement coupled to the medium frequency power source is represented by the circuit quantities transformed to the power source side. These are the inductance of the transmission line LL', the capacity CL', which largely compensates the voltage at inductance LL', and of the moving systems the transformed main inductances LHX' of the inductive receiver with capacities CKX' and the replacement resistors RX' for any transmit power. For long transmission lines, e.g. UHF voltage of 200 m, the general voltage spindle spindle spindle spindle spindle spindle spindle spindle spindle spindle spindle spindle spindle spindle spindle spindle spindle spindle spindle spindle spindle spindle spindle spindle spindle spindle spindle spindle spindle spindle spindle spindle spindle spindle spindle spindle spindle spindle spindle spindle spindle spindle spindle spindle spindle spindle spindle spindle spindle spindle spindle spindle spindle spindle spindle spindle spindle spindle spindle spindle spindle spindle spindle spindle spindle spindle spindle spindle spindle spindle spindle spindle spindle spindle spindle spindle spindle spindle spindle spindle spindle spindle spindle spindle spindle spindle spindle spindle spindle spindle spindle spindle spindle spindle spindle spindle spindle spindle spindle spindle spindle spindle spindle spindle spindle spindle spindle spindle spindle spindle spindle spindle spindle spindle spindle spindle spindle spindle spindle spindle spindle spindle spindle spindle spindle spindle spindle spindle spindle spindle spindle spindle spindle spindle spindle spindle spindle spindle spindle spindle spindle spindle spindle spindle spindle spindle spindle spindle spindle spindle spindle spindle spindle spindle spindle spindle spindle spindle spindle spindle spindle spindle spindle spindle spindle spindle spindle spindle spindle spindle spindle spindle spindle spindle spindle spindle spindle spindle spindle

The inductivity LL' of the transmission line and the capacity CL' are large energy storage units, corresponding to the lengths of the voltage gauges ULL' and UCL', connected between the output of the medium frequency power source and the inductive collectors of the moving systems. These energy storage units do not, however, affect the dynamic behaviour of the power transmission because, because of the constancy of the current I2, they do not change their energy content and therefore their voltages when the transmitted power changes, and the rate of change of the UHX' inductive collectors generated by the inventive transducer components on the moving system is limited in such a way that the fast-moving medium frequency source of constant current follows these changes without any deviation.

Err1:Expecting ',' delimiter: line 1 column 511 (char 510)

This power component of the actuator according to the invention differs from the power component shown in Fig. 10 of the technical publication cited only by a measuring resistor RZ for the detection of the intermediate DC current IZ and a measuring resistor RA for the detection of the consumer current IA. The lower permissible resistors are connected to power-reception stages IZ-EF, IA-EF, which process the small voltage measured current signals IZM, IAM from the received power for processing in the control electronics. These static signals are, as described below, only necessary for further training of the devices of the invention.

The essential difference with the current rectifier according to the state of the art is the information content and thus the formation of the SB signal that turns on and off the controllable power semiconductor TS. In the arrangement according to the invention, the SB signal is fed to the controllable power semiconductor TS from a pulse duration modulation stage PM2, which converts an input EM signal from the modulation stage into the pulsed SB signal in such a way that the ratio of the controllable power semiconductor's off time TW to the TS cycle time TZ is proportional to the value of the input EM signal and the TZ cell time is on the order of the half-period of the TM/2 fM frequency.

The pulse duration modulation stage PM2, which is fed a signal SY to specify the cycle time TZ and the signal EM to specify the switching time ratio TW/TZ, allows the stepless adjustment of the power taken up by the transmission line PL. A high frequency of the signal SY, for example, located in the double-medium frequency fM casing, results in a small value of the inductance LZ in the transformer and allows rapid changes in the transmitted power.

The control levels for regulating the consumer voltage UA to a set value UASOLL shall be subject to unreasonably high rates of change of the transmitted power if the control levels only switch the transmitted power supplied to the buffer capacitor between a few values or if the transmitted power PL follows a steady change to rapidly changing consumer power.

In the arrangement of the invention, a voltage regulator RU introduces a signal component EMU to the input EM signal of the pulse duration modulation stage PM2 whose rate of change is measured by the capacity of the buffer capacitor CP and the transmission function FU of the voltage regulator stage in such a way that the EMU signal component reaches its new final value only after the intermediate frequency power source's setting time TS is exceeded by the setting time TA of the AC adapter when the output current IA is changed by a jump.

The voltage-sensing stage UA-EF shown in Figure 3 is used to convert the high consumer voltage UA of e.g. 320 V into the voltage-according UAM supplied to the control stage and is not relevant to the invention.

Err1:Expecting ',' delimiter: line 1 column 269 (char 268)

A reduction of the dynamic deviations of the output voltage UA from its set value UASOLL in large and leap-like changes in the power consumption can be achieved if a current switching stage SA shown in Fig. 3 is supported by the output voltage control. To this end, a further signal component EMA is fed from the current nominal IAM via a delay stage VI to the E signal EM of the pulse duration modulation stage PM2. The EMA signal is measured so that, in the steady state via the modulation stage, a ratio of the power shut-off time TW of the controllable power supply semiconductor to the power supply cycle time TZ is achieved, at which time the transmission of the current transmitted by the transmission medium TS to the consumer is set at a constant voltage of the current input component P1 so that the changes in the current input of the signal TA1 are adjusted to the constant voltage of the input stage VI.

For the rectifier on the moving system, a small space requirement and a small weight are generally sought. For the inductance LZ, it has been shown that these values reach a minimum at a given wavelength of the intermediate circuit current IZ if, as shown in Fig. 7a and 7b, for two different lengths of locking intervals TW and thus for two different values of the transmitted power PL, the half-waves of the linear output voltage uB are symmetrical to the voltage pulses of the switch voltage uS. This symmetrical position of the input voltages LZ and SB is accurate, the pulse duration modulation stage SB2 is approximately the same as the synchronization time SY, the signal output power of the SSY is approximately half the signal duration of the TZ or the signal output power of the TZ, and the half-time modulation stage SB2 is approximately the same as the output power of the TZ, and the signal output power of the SSY is approximately the same as the output power of the TZ.

Claims (18)

1. Method for inductive transmission of electric power from a medium-frequency current source with a frequency (f_M) to one or more mobile consumers via an extended transmission line and inductive transducers (IA_X, IA_Y) coordinated with the mobile consumers, with down-circuit rectifier actuators, and for adjusting the power (P_LX, P_LY) taken from the transmission line and fed to buffer memories to which the mobile consumers are connected, the transmission line being fed from a current source with a medium-frequency current (I_L) which is constant in its effective value during the power transmission, characterized in that the output voltage (U_L) of the medium-frequency current source is adjusted within a maximum adjustment time (T_S), which lasts only a few half-periods of the medium frequency (f_M), continuously to the value which corresponds to the variable power taken altogether from the transmission line, and in that the rectifier actuator connected between the buffer memory and the inductive power transducer (IA) of each mobile consumer adjusts the average consumer power (P_L) taken from the transmission line and fed to the buffer memory, within an adjustment time (T_A) which is greater than the maximum adjustment time (T_S) of the medium-frequency current source, continuously and with a limited speed of change.
2. Method according to Claim 1, characterized in that the information for continuous adjustment of the power (P_L) taken by the inductive transducer (IA) from the transmission line and fed to the buffer memory and the information for the speed of change of this power and hence also the information for realizing the adjustment time (T_A) of the rectifier actuator are contained in a signal (SB) controlling the rectifier actuator.
3. Method according to Claim 2, characterized in that the output voltage (U_A) of the buffer memory, which is fed to the mobile consumers, is regulated to a specified setpoint value (U_ASOLL) and the information contained in the control signal (SB) of the rectifier actuator and intended for adjustment of the power (P_L) taken from the transmission line and the speed of change thereof are given by the power (P_v) taken up by the consumer and the dimensioning of the time behaviour of this regulation.
4. Method according to any of Claims 1 to 3, characterized in that the effective value of the current (I_L) fed from the medium-frequency current source into the transmission line has a constant value during the power transmission to the mobile systems and is continuously controllable in time ranges in which no power or only a power which is small compared with the maximum transmittable power is transmitted, with a speed of change which is substantially below the permissible speed of change of the power taken from the transmission line.
5. Method according to any of Claims 1 to 4, characterized in that the effective value of the medium-frequency current (I_L) fed into the transmission line is regulated to a specified setpoint value (I_LSOLL) .
6. Arrangement for inductive transmission of electric power from a medium-frequency current source with a frequency (f_M) to one or more mobile consumers via an extended transmission line and inductive transducers (IA_X, IA_Y) assigned to the mobile consumers with down-circuit rectifier actuators, and for adjusting the power (P_LX, P_LY) taken from the transmission line and fed to buffer memories to which the mobile consumers are connected, the transmission line being fed from a current source with a medium-frequency current (I_L) which is constant in its effective value during the power transmission, characterized in that the arrangement has suitable means which result in the output voltage (UL) of the medium-frequency current source adjusting within a maximum adjustment time (Ts), which lasts only a few half-periods of the medium frequency (fM), continuously to the value which corresponds to the variable power taken altogether from the transmission line, and in that the rectifier actuator connected between the buffer memory and the inductive power transducer (IA) of each mobile consumer adjusts the mean consumer power (PL) taken from the transmission line and fed to the buffer memory, within an adjustment time (TA) which is greater than the maximum adjustment time (Ts) of the medium-frequency current source, continuously and with a limited speed of change.
7. Arrangement according to Claim 6, characterized in that the transmission line located between medium-frequency current source and consumer is in the form of a series resonant circuit for this medium frequency.
8. Arrangement according to Claim 6 or 7, characterized in that the arrangement comprises a low-frequency/medium frequency converter (LF/MF converter) having an intermediate circuit d.c. voltage (U_G) buffered by a capacitor (C_G) and an invertor (W) formed from controllable power semiconductors (T1, T2, T3, T4) and controlled by a frequency generator with the frequency (F_M) of the medium-frequency current source for generating a pulse-like output a.c. voltage (u_W) and a coupling network which is connected to the output a.c. voltage (u_W) of the converter and has a series resonant circuit formed by an inductance (L₁) and a capacitance (C₁), the resonant frequency of which $1/\left(2,,\pi ,,\sqrt{L_1/C_1}\right)$ corresponds to the frequency (f_M) of the converter and in which the connections of the capacitor (C₁) are the outputs of the medium-frequency current source.
9. Arrangement according to Claim 8, characterized in that the inductance (L₁) and the capacitance (C₁) of the coupling network for achieving a transmittable rated power (P_N) are dimensioned according to the relationship $\sqrt{\left(L_1,/,C_1\right)}={U_{\mathrm{IN}}}^2/P_N,$ where U_IN is the effective rated voltage of the fundamental mode of the pulse-like output voltage (u_W) of an LF/MF converter.
10. Arrangement according to Claim 8 or 9, characterized in that a transformer (TR) connected between the capacitor (C₁) of the coupling network and a transmission line has a transformation ratio (W₁/W₂) which transforms the sum of equivalent resistances (R_XN), which are coupled in by inductive transducers (IA_X) on taking up the rated power in the transmission line, to a value (ER_XN') which is effective at the capacitor (C₁) and is equal to the oscillating resistance $\sqrt{\left(L_1,/,C_1\right)}$ of the coupling network.
11. Arrangement according to any of Claims 8 to 10, characterized in that the switching on and switching off of a controllable power semiconductor (T1, T2, T3, T4) of an LF/MF converter is effected by a pulse duration modulation stage (PM1) so that a pulse-like output a.c. voltage (u_W) having a variable pulse duration (T_D) forms and a signal (SD) for adjusting the pulse duration (T_D) and hence the effective value (U₁) of the fundamental mode of an output a.c. voltage (u_W) is fed to the pulse duration modulation stage.
12. Arrangement according to Claim 11, characterized in that a regulator (KOR) is present to which the setpoint value (I_LSOLL) of the medium-frequency current fed into the transmission line and the measured value (I_LM) of the medium-frequency current (I_L) actually fed in are supplied, and in that the regulator forms a component (SDR) of that input signal (SD) of a pulse duration modulation stage (BM1) which adjusts the pulse duration (T_D).
13. Arrangement according to any of Claims 6 to 12, characterized in that a capacitor (C_L) is connected in a series to the transmission line and is dimensioned in its capacitance so that it compensates the inductive voltage drop (U_LL) occurring at the inductance (L_L) of the transmission line.
14. Arrangement according to any of Claims 6 to 13, characterized in that a second pulse duration modulation stage (PM2) converts an input signal (EM) present at it into a pulse-like signal (SP) fed to a second controllable power semiconductor, in such a way that the ratio of the switching off time (T_w) of the second controllable power semiconductor (TS) to the cycle time (T_Z) is proportional to the value of the input signal (EM) and the cycle time (T_Z) is of the order of magnitude of half the cycle duration (T_M/2) of the medium frequency (f_M).
15. Arrangement according to Claim 14, characterized in that a voltage control stage (RU) which regulates the output voltage (U_A) of a buffer capacitor (C_P) to its setpoint value (U_ASOLL) is present and feeds a signal component (EMU) of the input signal (EM) to the second pulse duration modulation stage (PM2) and in that the speed of change of the signal components (EMU) is dimensioned by the capacitance of the buffer capacitor (Cp) and the transmission function (FU) of the voltage control stage (RU) in such a way that, in the case of an abrupt change of the output current (I_A) of the buffer capacitor, the signal component (EMU) reaches its new end value only after the adjustment time (T_A) of the rectifier actuator, which adjustment time is longer compared with the maximum adjustment time (T_S) of the medium-frequency current source.
16. Arrangement according to Claim 14 or 15, characterized in that an active attenuation stage (AD) feeds a further signal component (EMD) of the input signal (EM) to the second pulse duration modulation stage (PM2) for attenuating natural oscillations of the intermediate circuit current (I_Z) in the oscillatable part-circuit consisting of the parallel resonant circuit (L_H", C_K) of the inductive transducer, a rectifier (G2) and an intermediate circuit inductance (L_Z).
17. Arrangement according to any of Claims 14 to 16, characterized in that a current application stage (SA) with a delay stage (VI) is present, which feeds to the second pulse modulation stage (PM2) a signal component (EMA) of the input signal (EM), which signal component in the steady state is proportional to the consumer current and is dimensioned so that, via the second pulse modulation stage (PM2), it establishes a ratio of the switching off time (T_W) of the second controllable power semiconductor to a cycle time (T_Z) in which the power (P_L) taken from the transmission line corresponds approximately to the consumer power (P_V), and which transmits abrupt changes of the consumer current (I_A) with a delay to the signal component (EMA) so that the adjustment time (T_A) of the rectifier actuator which is longer compared with the maximum adjustment time (T_S) of the medium-frequency current source is maintained.
18. Arrangement according to any of Claims 14 to 17, characterized in that a synchronization signal (SY) which is generated by a synchronization stage (SS) from a medium-frequency input current (I_E) or an input voltage (U_E) of the rectifier actuator is fed to the second pulse duration modulation stage (PM2), which synchronization signal (SY) influences the formation of an output signal (SB) of a pulse duration modulation stage in such a way that the cycle time (T_Z) of the signal (SB) corresponds exactly to the duration of a half-period ((T_L/2) of the medium frequency (f_M) and the switching off time (T_w) of the second controllable power semiconductor (TS) is approximately half before and half behind the peak value of the output voltage (u_B) of a rectifier (G2).