You can just connect a thyristor between the output of the fuse and ground. The fuse will blow as soon as there is power from the battery. Look up "crowbar circuit"
You don't need to increase the voltage to blow a fuse. If you increased the voltage you might damage what is connected to the fuse. To blow a fuse, you need several times its rated current. You should that increased current by reducing the resistance of the load, not by increasing the voltage. If you increase the voltage and keep the load the same, you would need maybe 100 volts or more, and you would probably cause the load to fail before the fuse failed. Also, some loads might be disconnected at some times so it wouldn't matter how much you increased the voltage, the fuse would never blow.
You might want to use a buck regulator that would reduce the voltage, and at the same time increase the current, so that the fuse would blow while taking less than the fuse rating from the supply. However, there is little point. The car battery will supply around 500 amps to turn the starter motor, so a spike of 100 amps to blow a 30 amp fuse isn't a problem.